Version 1.82 of ai12s/amd2xcon.txt

Unformatted version of ai12s/amd2xcon.txt version 1.82
Other versions for file ai12s/amd2xcon.txt

!comment This file contains Corrigendum conflicts for Amendment 3 (Ada 202x).
!comment Conflicts occur when multiple issues change the same
!comment paragraph of the standard.
!comment This file (and the reading of it in the program) would need to
!comment be changed for a new Corrigendum or Amendment.
!comment The paragraphs must be in sorted order!!
!corrigendum 1.1.3(17/3)
!AI-0179-1
!AI-0265-1
@dinsa An implementation conforming to this International Standard may provide additional aspects, attributes, library units, and pragmas. However, it shall not provide any aspect, attribute, library unit, or pragma having the same name as an aspect, attribute, library unit, or pragma (respectively) specified in a Specialized Needs Annex unless the provided construct is either as specified in the Specialized Needs Annex or is more limited in capability than that required by the Annex. A program that attempts to use an unsupported capability of an Annex shall either be identified by the implementation before run time or shall raise an exception at run time. @dinst For an implementation that conforms to this Reference Manual, the implementation of a language-defined unit shall abide by all postconditions, type invariants, and default initial conditions specified for the unit by this document (see 11.4.2).
!corrigendum 1.2(3/2)
!AI-0058-1
!AI-0224-1
@drepl ISO/IEC 1539-1:2004, @i<Information technology @emdash Programming languages @emdash Fortran @emdash Part 1: Base language>. @dby ISO/IEC 1539-1:2018, @i<Information technology @emdash Programming languages @emdash Fortran @emdash Part 1: Base language>.
!corrigendum 2.1(4.1/3)
!AI-0004-1
!AI-0263-1
@drepl The semantics of an Ada program whose text is not in Normalization Form KC (as defined by Clause 21 of ISO/IEC 10646:2011) is implementation defined. @dby The semantics of an Ada program whose text is not in Normalization Form C (as defined by Clause 21 of ISO/IEC 10646:2017) is implementation defined.
!corrigendum 2.2(9)
!AI-0125-3
!AI-0212-1
@drepl & @ @ ' @ @ ( @ @ ) @ @ * @ @ + @ @ , @ @ @endash @ @ . @ @ / @ @ : @ @ ; @ @ < @ @ = @ @ @> @ @ | @dby & @ @ ' @ @ ( @ @ ) @ @ * @ @ + @ @ , @ @ @endash @ @ . @ @ / @ @ : @ @ ; @ @ < @ @ = @ @ @> @ @ @@ @ @ [ @ @ ] @ @ |
!corrigendum 2.3(4/3)
!AI-0004-1
!AI-0263-1
@dinsa An @fa<identifier> shall not contain two consecutive characters in category @fa<punctuation_connector>, or end with a character in that category. @dinst @s8<@i<Legality Rules>>
An identifier shall only contain characters that may be present in Normalization Form KC (as defined by Clause 21 of ISO/IEC 10646:2017).
!corrigendum 3.1(6/3)
!AI-0061-1
!AI-0308-1
@drepl Each of the following is defined to be a declaration: any @fa<basic_declaration>; an @fa<enumeration_literal_specification>; a @fa<discriminant_specification>; a @fa<component_declaration>; a @fa<loop_parameter_specification>; an @fa<iterator_specification>; a @fa<parameter_specification>; a @fa<subprogram_body>; an @fa<extended_return_object_declaration>; an @fa<entry_declaration>; an @fa<entry_index_specification>; a @fa<choice_parameter_specification>; a @fa<generic_formal_parameter_declaration>. @dby Each of the following is defined to be a declaration: any @fa<basic_declaration>; an @fa<enumeration_literal_specification>; a @fa<discriminant_specification>; a @fa<component_declaration>; a @fa<defining_identifier> of an @fa<iterated_component_association>; a @fa<loop_parameter_specification>; a @fa<defining_identifier> of a @fa<chunk_specification>; an @fa<iterator_specification>; a @fa<defining_identifier> of an @fa<iterator_parameter_specification>; a @fa<parameter_specification>; a @fa<subprogram_body>; an @fa<extended_return_object_declaration>; an @fa<entry_declaration>; an @fa<entry_index_specification>; a @fa<choice_parameter_specification>; a @fa<generic_formal_parameter_declaration>.
!corrigendum 3.2.4(1/3)
!AI-0396-1
!AI-0419-1
@drepl The language-defined @i<predicate aspects> Static_Predicate and Dynamic_Predicate may be used to define properties of subtypes. A @i<predicate specification> is an @fa<aspect_specification> for one of the two predicate aspects. General rules for aspects and @fa<aspect_specification>s are found in Clause 13 (13.1 and 13.1.1 respectively). @dby The language-defined @i<predicate aspects> Static_Predicate and Dynamic_Predicate may be used to define properties of subtypes. A @i<predicate specification> is an @fa<aspect_specification> for one of the two predicate aspects. General rules for aspects and @fa<aspect_specification>s are found in Clause 13 (13.1 and 13.1.1 respectively). The predicate aspects are assertion aspects (see 11.4.2). The predicate aspects are not inherited, but their effects are additive, as defined below.
!corrigendum 3.2.4(31/4)
!AI-0301-1
!AI-0333-1
!AI-0432-1
@drepl @xindent<On every subtype conversion, a check is performed that the operand satisfies the predicates of the target subtype. This includes all parameter passing, except for certain parameters passed by reference, which are covered by the following rule: After normal completion and leaving of a subprogram, for each @b<in out> or @b<out> parameter that is passed by reference, a check is performed that the value of the parameter satisfies the predicates of the subtype of the actual. For an object created by an @fa<object_declaration> with no explicit initialization @fa<expression>, or by an uninitialized @fa<allocator>, if any subcomponents have @fa<default_expression>s, a check is performed that the value of the created object satisfies the predicates of the nominal subtype.> @dby @xindent<On a subtype conversion, a check is performed that the operand satisfies the predicates of the target subtype, except for certain view conversions (see 4.6). In addition, after normal completion and leaving of a subprogram, for each @b<in out> or @b<out> parameter that is passed by reference, a check is performed that the value of the parameter satisfies the predicates of the subtype of the actual. For an object created by an @fa<object_declaration> with no explicit initialization @fa<expression>, or by an uninitialized @fa<allocator>, if the types of any parts have specified Default_Value or Default_Component_Value aspects, or any subcomponents have @fa<default_expression>s, a check is performed that the value of the created object satisfies the predicates of the nominal subtype.>
!corrigendum 3.3(6)
!AI-0061-1
!AI-0308-1
@dinsa @xbullet<a loop parameter;> @dinst @xbullet<the index parameter of an @fa<iterated_component_association>;> @xbullet<the chunk parameter of a @fa<chunk_specification>;>
!corrigendum 3.3(18.1/3)
!AI-0061-1
!AI-0308-1
!AI-0392-1
@drepl @xbullet<a loop parameter unless specified to be a variable for a generalized loop (see 5.5.2);> @dby @xbullet<a loop parameter that is specified to be a variable for a generalized loop (see 5.5.2);>
!corrigendum 3.3(21/3)
!AI-0392-1
!AI-0407-1
@drepl @xbullet<the object denoted by a @fa<function_call> or an @fa<aggregate>;> @dby @xbullet<the current instance of a type other than a protected type, if the current instance is an object and not a value (see 8.6);>
!corrigendum 3.3(21.1/3)
!AI-0125-3
!AI-0226-1
!AI-0392-1
@ddel @xbullet<the result of evaluating a @fa<qualified_expression>;>
!corrigendum 3.3(23/3)
!AI-0191-1
!AI-0294-1
@drepl At the place where a view of an object is defined, a @i<nominal subtype> is associated with the view. The object's @i<actual subtype> (that is, its subtype) can be more restrictive than the nominal subtype of the view; it always is if the nominal subtype is an @i<indefinite subtype>. A subtype is an indefinite subtype if it is an unconstrained array subtype, or if it has unknown discriminants or unconstrained discriminants without defaults (see 3.7); otherwise, the subtype is a @i<definite> subtype (all elementary subtypes are definite subtypes). A class-wide subtype is defined to have unknown discriminants, and is therefore an indefinite subtype. An indefinite subtype does not by itself provide enough information to create an object; an additional @fa<constraint> or explicit initialization @fa<expression> is necessary (see 3.3.1). A component cannot have an indefinite nominal subtype. @dby At the place where a view of an object is defined, a @i<nominal subtype> is associated with the view. The @i<nominal type> of a view is the type of the nominal subtype of the view. The object's @i<actual subtype> (that is, its subtype) can be more restrictive than the nominal subtype of the view; it always is more restrictive if the nominal subtype is an @i<indefinite subtype>. A subtype is an indefinite subtype if it is an unconstrained array subtype, or if it has unknown discriminants or unconstrained discriminants without defaults (see 3.7); otherwise, the subtype is a @i<definite> subtype (all elementary subtypes are definite subtypes). A class-wide subtype is defined to have unknown discriminants, and is therefore an indefinite subtype. An indefinite subtype does not by itself provide enough information to create an object; an additional @fa<constraint> or explicit initialization @fa<expression> is necessary (see 3.3.1). A component cannot have an indefinite nominal subtype.
!corrigendum 3.3(23.7/3)
!AI-0226-1
!AI-0228-1
@dinsa @xbullet<it is part of the object denoted by a @fa<function_call> or @fa<aggregate>; or> @dinst @xbullet<it is a value conversion or @fa<qualified_expression> where the operand denotes a view of a composite object that is known to be constrained; or>
!corrigendum 3.3.1(8.1/2)
!AI-0192-1
!AI-0404-1
@drepl A component of an object is said to @i<require late initialization> if it has an access discriminant value constrained by a per-object expression, or if it has an initialization expression that includes a name denoting the current instance of the type or denoting an access discriminant. @dby A component of an object is said to @i<require late initialization> if: @xbullet<it has an access discriminant value constrained by a per-object expression; or> @xbullet<it has an initialization expression that includes a name denoting an access discriminant; or> @xbullet<it has an initialization expression that includes a reference to the current instance of the type either by name or implicitly as the target object of a call.>
!corrigendum 3.3.1(23/3)
!AI-0061-1
!AI-0308-1
@drepl @xindent<@s9<8 As indicated above, a stand-alone object is an object declared by an @fa<object_declaration>. Similar definitions apply to "stand-alone constant" and "stand-alone variable." A subcomponent of an object is not a stand-alone object, nor is an object that is created by an @fa<allocator>. An object declared by a @fa<loop_parameter_specification>, @fa<iterator_specification>, @fa<parameter_specification>, @fa<entry_index_specification>, @fa<choice_parameter_specification>, @fa<extended_return_statement>, or a @fa<formal_object_declaration> of mode @b<in out> is not considered a stand-alone object.>> @dby @xindent<@s9<8 As indicated above, a stand-alone object is an object declared by an @fa<object_declaration>. Similar definitions apply to "stand-alone constant" and "stand-alone variable". A subcomponent of an object is not a stand-alone object, nor is an object that is created by an @fa<allocator>. An object declared by a @fa<loop_parameter_specification>, @fa<iterator_specification>, @fa<iterated_component_association>, @fa<chunk_specification>, @fa<parameter_specification>, @fa<entry_index_specification>, @fa<choice_parameter_specification>, @fa<extended_return_statement>, or a @fa<formal_object_declaration> of mode @b<in out> is not considered a stand-alone object.>>
!corrigendum 3.5(55.1/4)
!AI-0020-1
!AI-0225-1
@ddel For a @fa<prefix> X that denotes an object of a scalar type (after any implicit dereference), the following attributes are defined:
!corrigendum 3.9(6/2)
!AI-0241-1
!AI-0302-1
!AI-0399-1
@drepl @xcode<@b<package> Ada.Tags @b<is>
@b<pragma> Preelaborate(Tags); @b<type> Tag @b<is private>; @b<pragma> Preelaborable_Initialization(Tag);>
@dby @xcode<@b<package> Ada.Tags
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is> @b<type> Tag @b<is private>
@b<with> Preelaborable_Initialization;>
!corrigendum 3.9(18.2/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<generic>
@b<type> T (<@>) @b<is abstract tagged limited private>; @b<type> Parameters (<@>) @b<is limited private>; @b<with function> Constructor (Params : @b<not null access> Parameters)
@b<return> T @b<is abstract>;
@b<function> Ada.Tags.Generic_Dispatching_Constructor
(The_Tag : Tag;
Params : @b<not null access> Parameters) @b<return> T'Class
@b<with> Convention =@> Intrinsic;
@b<pragma> Preelaborate(Generic_Dispatching_Constructor);> @dby @xcode<@b<generic>
@b<type> T (<@>) @b<is abstract tagged limited private>; @b<type> Parameters (<@>) @b<is limited private>; @b<with function> Constructor (Params : @b<not null access> Parameters)
@b<return> T @b<is abstract>;
@b<function> Ada.Tags.Generic_Dispatching_Constructor
(The_Tag : Tag;
Params : @b<not null access> Parameters) @b<return> T'Class
@b<with> Preelaborate, Convention =@> Intrinsic,
Nonblocking, Global =@> @b<in out synchronized>;>
!corrigendum 3.9.2(1/2)
!AI-0342-1
!AI-0419-1
@drepl The primitive subprograms of a tagged type, the subprograms declared by @fa<formal_abstract_subprogram_declaration>s, and the stream attributes of a specific tagged type that are available (see 13.13.2) at the end of the declaration list where the type is declared are called @i<dispatching operations>. A dispatching operation can be called using a statically determined @i<controlling> tag, in which case the body to be executed is determined at compile time. Alternatively, the controlling tag can be dynamically determined, in which case the call @i<dispatches> to a body that is determined at run time; such a call is termed a @i<dispatching call>. As explained below, the properties of the operands and the context of a particular call on a dispatching operation determine how the controlling tag is determined, and hence whether or not the call is a dispatching call. Run-time polymorphism is achieved when a dispatching operation is called by a dispatching call. @dby The primitive subprograms of a tagged type, the subprograms declared by @fa<formal_abstract_subprogram_declaration>s, the Put_Image attribute (see 4.10) of a specific tagged type, and the stream attributes of a specific tagged type that are available (see 13.13.2) at the end of the declaration list where the type is declared are called @i<dispatching operations>. A dispatching operation can be called using a statically determined @i<controlling> tag, in which case the body to be executed is determined at compile time. Alternatively, the controlling tag can be dynamically determined, in which case the call @i<dispatches> to a body that is determined at run time; such a call is termed a @i<dispatching call>. As explained below, the properties of the operands and the context of a particular call on a dispatching operation determine how the controlling tag is determined, and hence whether or not the call is a dispatching call. Run-time polymorphism is achieved when a dispatching operation is called by a dispatching call.
!corrigendum 3.9.3(7)
!AI-0320-1
!AI-0413-1
@drepl A call on an abstract subprogram shall be a dispatching call; nondispatching calls to an abstract subprogram are not allowed. @dby A call on an abstract subprogram shall be a dispatching call; nondispatching calls to an abstract subprogram are not allowed. In addition to the places where Legality Rules normally apply (see 12.3), these rules also apply in the private part of an instance of a generic unit.
If the @fa<name> or @fa<prefix> given in an @fa<iterator_procedure_call> (see 5.5.3) denotes an abstract subprogram, the subprogram shall be a dispatching subprogram.
!corrigendum 3.10(9/3)
!AI-0228-1
!AI-0324-1
@drepl A view of an object is defined to be @i<aliased> if it is defined by an @fa<object_declaration>, @fa<component_definition>, @fa<parameter_specification>, or @fa<extended_return_object_declaration> with the reserved word @b<aliased>, or by a renaming of an aliased view. In addition, the dereference of an access-to-object value denotes an aliased view, as does a view conversion (see 4.6) of an aliased view. The current instance of an immutably limited type (see 7.5) is defined to be aliased. Finally, a formal parameter or generic formal object of a tagged type is defined to be aliased. Aliased views are the ones that can be designated by an access value. @dby A view of an object is defined to be @i<aliased> if it is defined by an @fa<object_declaration>, @fa<component_definition>, @fa<parameter_specification>, or @fa<extended_return_object_declaration> with the reserved word @b<aliased>, or by a renaming of an aliased view. In addition, the dereference of an access-to-object value denotes an aliased view, as does a view conversion (see 4.6) of an aliased view. A @fa<qualified_expression> denotes an aliased view when the operand denotes an aliased view. The current instance of an immutably limited type (see 7.5) is defined to be aliased. Finally, a formal parameter or generic formal object of a tagged type is defined to be aliased. Aliased views are the ones that can be designated by an access value.
!corrigendum 3.10.2(9.1/3)
!AI-0236-1
!AI-0292-1
@drepl @xbullet<The accessibility level of a @fa<conditional_expression> is the accessibility level of the evaluated @i<dependent_>@fa<expression>.> @dby @xbullet<The accessibility level of a @fa<conditional_expression> (see 4.5.7) is the accessibility level of the evaluated @i<dependent_>@fa<expression>.>
@xbullet<The accessibility level of a @fa<declare_expression> (see 4.5.9) is the accessibility level of the @i<body_>@fa<expression>.>
!corrigendum 3.10.2(10.3/3)
!AI-0278-1
!AI-0390-1
@drepl @xinbull<If the result is of an anonymous access type and is the operand of an explicit conversion, the master is that of the target type of the conversion;> @dby @xinbull<If the result is of an anonymous access type and is converted to a (named or anonymous) access type, the master is determined following the rules given below for determining the master of an object created by an allocator (even if the access result is of an access-to-subprogram type);>
!corrigendum 3.10.2(10.5/3)
!AI-0345-1
!AI-0372-1
@drepl If the call itself defines the result of a function to which one of the above rules applies, these rules are applied recursively; @dby If the call itself defines the result of a function @i<F>, or has an accessibility level that is tied to the result of such a function @i<F>, then the master of the call is that of the master of the call invoking @i<F>;
!corrigendum 3.10.2(16.1/3)
!AI-0236-1
!AI-0317-1
@drepl In the above rules, the operand of a view conversion, parenthesized expression or @fa<qualified_expression> is considered to be used in a context if the view conversion, parenthesized expression or @fa<qualified_expression> itself is used in that context. Similarly, a @i<dependent_>@fa<expression> of a @fa<conditional_expression> is considered to be used in a context if the @fa<conditional_expression> itself is used in that context. @dby In the above rules, the operative constituents of a @fa<name> or @fa<expression> (see 4.4) are considered to be used in a given context if the enclosing @fa<name> or @fa<expression> is used in that context.
!corrigendum 3.10.2(19.1/3)
!AI-0392-1
!AI-0406-1
@drepl @xbullet<The statically deeper relationship does not apply to the accessibility level of the type of a stand-alone object of an anonymous access-to-object type; that is, such an accessibility level is not considered to be statically deeper, nor statically shallower, than any other.> @dby @xinbull<the anonymous type of an access parameter specifying an access-to-object type;> @xinbull<the type of a stand-alone object of an anonymous access-to-object type;> @xinbull<a @fa<raise_expression>;> @xinbull<a descendant of a generic formal type;> @xinbull<a descendant of a type declared in a generic formal package.> @xindent<When the statically deeper relationship does not apply, the accessibility level is not considered to be statically deeper, nor statically shallower, than any other.>
!corrigendum 3.10.2(19.2/4)
!AI-0277-1
!AI-0324-1
!AI-0345-1
@ddel @xbullet<Inside a return statement that applies to a function or generic function @i<F>, or the return expression of an expression function @i<F>, when determining whether the accessibility level of an explicitly aliased parameter of @i<F> is statically deeper than the level of the return object of @i<F>, the level of the return object is considered to be the same as that of the level of the explicitly aliased parameter; for statically comparing with the level of other entities, an explicitly aliased parameter of @i<F> is considered to have the accessibility level of the body of @i<F>.>
!corrigendum 4.1.3(13.1/3)
!AI-0204-1
!AI-0427-1
@drepl For a subprogram whose first parameter is an access parameter, the prefix of any prefixed view shall denote an aliased view of an object. @dby For a prefixed view of a subprogram whose first formal parameter is an access parameter, the prefix shall be legal as the @fa<prefix> of an @fa<attribute_reference> with @fa<attribute_designator> Access appearing as the first actual parameter in a call on the unprefixed view of the subprogram.
!corrigendum 4.1.4(6)
!AI-0242-1
!AI-0262-1
@drepl In an @fa<attribute_reference>, if the @fa<attribute_designator> is for an attribute defined for (at least some) objects of an access type, then the @fa<prefix> is never interpreted as an @fa<implicit_dereference>; otherwise (and for all @fa<range_attribute_reference>s), if the type of the @fa<name> within the @fa<prefix> is of an access type, the @fa<prefix> is interpreted as an @fa<implicit_dereference>. Similarly, if the @fa<attribute_designator> is for an attribute defined for (at least some) functions, then the @fa<prefix> is never interpreted as a parameterless @fa<function_call>; otherwise (and for all @fa<range_attribute_reference>s), if the @fa<prefix> consists of a @fa<name> that denotes a function, it is interpreted as a parameterless @fa<function_call>. @dby In an @fa<attribute_reference> that is not a @fa<reduction_attribute_reference>, if the @fa<attribute_designator> is for an attribute defined for (at least some) objects of an access type, then the @fa<prefix> is never interpreted as an @fa<implicit_dereference>; otherwise (and for all @fa<range_attribute_reference>s and @fa<reduction_attribute_reference>s), if there is a @fa<prefix> and the type of the @fa<name> within the @fa<prefix> is of an access type, the @fa<prefix> is interpreted as an @fa<implicit_dereference>. Similarly, if the @fa<attribute_designator> is for an attribute defined for (at least some) functions, then the @fa<prefix> is never interpreted as a parameterless @fa<function_call>; otherwise (and for all @fa<range_attribute_reference>s and @fa<reduction_attribute_reference>s), if there is a @fa<prefix> and the @fa<prefix> consists of a @fa<name> that denotes a function, it is interpreted as a parameterless @fa<function_call>.
!corrigendum 4.2(4)
!AI-0325-1
!AI-0373-1
@drepl The expected type for a @fa<primary> that is a @fa<string_literal> shall be a single string type. @dby The expected type for a @fa<primary> that is a @fa<string_literal> shall be a single string type or a type with a specified String_Literal aspect (see 4.2.1). In either case, the @fa<string_literal> is interpreted to be of its expected type. If the expected type of an integer literal is a type with a specified Integer_Literal aspect (see 4.2.1), the literal is interpreted to be of its expected type; otherwise it is interpreted to be of type @i<universal_integer>. If the expected type of a real literal is a type with a specified Real_Literal aspect (see 4.2.1), it is interpreted to be of its expected type; otherwise, it is interpreted to be of type @i<universal_real>.
!corrigendum 4.2(6)
!AI-0295-1
!AI-0325-1
@drepl For each character of a @fa<string_literal> with a given expected string type, there shall be a corresponding @fa<defining_character_literal> of the component type of the expected string type. @dby If the expected type for a string_literal is a string type, then for each character of the @fa<string_literal> there shall be a corresponding @fa<defining_character_literal> of the component type of the expected string type.
!corrigendum 4.2(10)
!AI-0295-1
!AI-0325-1
@drepl The evaluation of a @fa<string_literal> that is a @fa<primary> yields an array value containing the value of each character of the sequence of characters of the @fa<string_literal>, as defined in 2.6. The bounds of this array value are determined according to the rules for @fa<positional_array_aggregate>s (see 4.3.3), except that for a null string literal, the upper bound is the predecessor of the lower bound. @dby The evaluation of a @fa<string_literal> that is a @fa<primary> and has an expected type that is a string type, yields an array value containing the value of each character of the sequence of characters of the @fa<string_literal>, as defined in 2.6. The bounds of this array value are determined according to the rules for @fa<positional_array_aggregate>s (see 4.3.3), except that for a null string literal, the upper bound is the predecessor of the lower bound. In other cases, the effect of evaluating a @fa<string_literal> is determined by the String_Literal aspect that applies (see 4.2.1).
!corrigendum 4.2(11)
!AI-0295-1
!AI-0325-1
@drepl For the evaluation of a @fa<string_literal> of type @i<T>, a check is made that the value of each character of the @fa<string_literal> belongs to the component subtype of @i<T>. For the evaluation of a null string literal, a check is made that its lower bound is greater than the lower bound of the base range of the index type. The exception Constraint_Error is raised if either of these checks fails. @dby For the evaluation of a @fa<string_literal> of a string type @i<T>, a check is made that the value of each character of the @fa<string_literal> belongs to the component subtype of @i<T>. For the evaluation of a null string literal of a string type, a check is made that its lower bound is greater than the lower bound of the base range of the index type. The exception Constraint_Error is raised if either of these checks fails.
!corrigendum 4.2.1(0)
!AI-0249-1
!AI-0295-1
!AI-0312-1
!AI-0325-1
!AI-0342-1
!AI-0373-1
!AI-0386-1
!AI-0394-1
!AI-0403-1
!AI-0419-1
!AI-0429-1
@dinsc
Using one or more of the aspects defined below, a type may be specified to allow the use of one or more kinds of literals as values of the type.
@s8<@i<Static Semantics>>
The following type-related operational aspects (collectively known as @i<user-defined literal aspects>) may be specified for a type @i<T>:
@xhang<@xterm<Integer_Literal> This aspect is specified by a @i<function_>@fa<name> that statically denotes a function with a result type of @i<T> and one @b<in> parameter that is of type String and is not explictly aliased.>
@xhang<@xterm<Real_Literal> This aspect is specified by a @i<function_>@fa<name> that statically denotes a function with a result type of @i<T> and one @b<in> parameter that is of type String and is not explictly aliased, and optionally a second function (overloading the first) with a result type of @i<T> and two @b<in> parameters of type String that are not explicitly aliased.>
@xhang<@xterm<String_Literal> This aspect is specified by a @i<function_>@fa<name> that statically denotes a function with a result type of @i<T> and one @b<in> parameter that is of type Wide_Wide_String and is not explictly aliased.>
User-defined literal aspects are nonoverridable (see 13.1.1).
When a numeric literal is interpreted as a value of a non-numeric type @i<T> or a @fa<string_literal> is interpreted a value of a type @i<T> that is not a string type (see 4.2), it is equivalent to a call to the subprogram denoted by the corresponding aspect of @i<T>: the Integer_Literal aspect for an integer literal, the Real_Literal aspect for a real literal, and the String_Literal aspect for a @fa<string_literal>. The actual parameter of this notional call is a @fa<string_literal> representing a sequence of characters that is the same as the sequence of characters in the original numeric literal, or the sequence represented by the original string literal.
Such a literal is said to be a @i<user-defined literal>.
When a named number that denotes a value of type @i<universal_integer> is interpreted as a value of a non-numeric type @i<T>, it is equivalent to a call to the function denoted by the Integer_Literal aspect of @i<T>. The actual parameter of this notional call is a String having a textual representation of a decimal integer literal optionally preceded by a minus sign, representing the same value as the named number.
When a named number that denotes a value of type @i<universal_real> is interpreted as a value of a non-numeric type @i<T>, it is equivalent to a call to the two-parameter function denoted by the Real_Literal aspect of @i<T>, if any. The actual parameters of this notional call are each a String with the textual representation of a decimal integer literal, with the first optionally preceded by a minus sign, where the first String represents the same value as the numerator, and the second the same value as the denominator, of the named number when represented as a rational number in lowest terms, with a positive denominator.
@s8<@i<Legality Rules>>
The Integer_Literal or Real_Literal aspect shall not be specified for a type @i<T> if the full view of @i<T> is a numeric type. The String_Literal aspect shall not be specified for a type @i<T> if the full view of @i<T> is a string type.
For a nonabstract type, the function directly specified for a user-defined literal aspect shall not be abstract.
For a tagged type with a partial view, a user-defined literal aspect shall not be directly specified on the full type.
If a nonabstract tagged type inherits any user-defined literal aspect, then each inherited aspect shall be directly specified as a nonabstract function for the type unless the inherited aspect denotes a nonabstract function, or functions, and the type is a null extension.
If a named number that denotes a value of type @i<universal_integer> is interpreted as a value of a non-numeric type @i<T>, @i<T> shall have an Integer_Literal aspect. If a named number that denotes a value of type @i<universal_real> is interpreted as a value of a non-numeric type @i<T>, @i<T> shall have a Real_Literal aspect, and the aspect shall denote a function that has two @b<in> parameters, both of type String, with result of type @i<T>.
In addition to the places where Legality Rules normally apply (see 12.3), these rules also apply in the private part of an instance of a generic unit.
@s8<@i<Bounded (Run-Time) Errors>>
It is a bounded error if the evaluation of a literal or named number that has an expected type with a specified user-defined literal aspect propagates an exception. Either Program_Error or the exception propagated by the evaluation is raised at the point of use of the value of the literal or named number. If it is recognized prior to run time that evaluation of such a literal or named number will inevitably (if executed) result in such a bounded error, then this may be reported as an error prior to run time.
@s8<@i<Examples>>
@i<Examples of the specification and use of user-defined literals:>
@xcode<@b<subtype> Roman_Character @b<is> Wide_Wide_Character
@b<with> Static_Predicate =@>
Roman_Character @b<in> 'I' | 'V' | 'X' | 'L' | 'C' | 'D' | 'M';>
@xcode<Max_Roman_Number : @b<constant> := 3_999; --@ft<@i< MMMCMXCIX>>>
@xcode<@b<type> Roman_Number @b<is range> 1 .. Max_Roman_Number
@b<with> String_Literal =@> To_Roman_Number;>
@xcode<@b<function> To_Roman_Number (S : Wide_Wide_String) @b<return> Roman_Number
@b<with> Pre =@> S'Length @> 0 @b<and then>
(@b<for all> Char @b<of> S =@> Char @b<in> Roman_Character);>
@xcode<@b<function> To_Roman_Number (S : Wide_Wide_String) @b<return> Roman_Number @b<is>
(@b<declare>
R : @b<constant array> (Integer @b<range> <@>) @b<of> Roman_Number :=
(@b<for> D @b<in> S'Range =@> Roman_Digit'Enum_Rep (Roman_Digit'Wide_Wide_Value (''' & S(D) & '''))); --@ft<@i< See 3.5.2 and 13.4>>
@b<begin>
[@b<for> I @b<in> R'Range =@> (@b<if> I < R'Last @b<and then> R(I) < R(I + 1) @b<then> -1 @b<else> 1) * R(I)] 'Reduce("+", 0)
);>
@xcode<X : Roman_Number := "III" "IV" "XII"; --@ft<@i< 144 (that is, CXLIV)>>>
!corrigendum 4.3(2)
!AI-0127-1
!AI-0212-1
@drepl @xindent<@fa<aggregate>@fa<@ ::=@ >@fa<record_aggregate>@ |@ @fa<extension_aggregate>@ |@ @fa<array_aggregate>> @dby @xindent<@fa<aggregate>@fa<@ ::=@ >@hr @ @ @ @ @fa<record_aggregate>@ |@ @fa<extension_aggregate>@ |@ @fa<array_aggregate>@hr @ @ |@ @fa<delta_aggregate>@ |@ @fa<container_aggregate>>
!corrigendum 4.3(3/2)
!AI-0127-1
!AI-0212-1
!AI-0307-1
@drepl The expected type for an @fa<aggregate> shall be a single array type, record type, or record extension. @dby The expected type for an @fa<aggregate> shall be a single array type, a single type with the Aggregate aspect specified, or a single descendant of a record type or of a record extension.
!corrigendum 4.3.1(17/3)
!AI-0086-1
!AI-0127-1
@drepl The value of a discriminant that governs a @fa<variant_part> @i<P> shall be given by a static expression, unless @i<P> is nested within a @fa<variant> @i<V> that is not selected by the discriminant value governing the @fa<variant_part> enclosing @i<V>. @dby For a @fa<record_aggregate> or @fa<extension_aggregate>, if a @fa<variant_part> @i<P> is nested within a @fa<variant> @i<V> that is not selected by the discriminant value governing the @fa<variant_part> enclosing @i<V>, then there is no restriction on the discriminant governing @i<P>. Otherwise, the value of the discriminant that governs @i<P> shall be given by a static expression, or by a nonstatic expression having a constrained static nominal subtype. In this latter case of a nonstatic expression, there shall be exactly one @fa<discrete_choice_list> of @i<P> that covers each value that belongs to the nominal subtype and satisfies the predicates of the subtype, and there shall be at least one such value.
!corrigendum 4.3.1(17.1/2)
!AI-0127-1
!AI-0418-1
@dinsa A @fa<record_component_association> for a discriminant without a @fa<default_expression> shall have an @fa<expression> rather than <@>.
@dinss A @fa<record_component_association> of the @fa<record_component_association_list> of a @fa<record_delta_aggregate> shall not:
@xbullet<use the box compound delimiter <@> rather than an @fa<expression>;>
@xbullet<have an @fa<expression> of a limited type;>
@xbullet<omit the @fa<component_choice_list>; or>
@xbullet<have a @fa<component_choice_list> that is an @b<others> choice.>
For a @fa<record_delta_aggregate>, no two @i<component_>@fa<selector_name>s shall denote components declared within different @fa<variant>s of the same @fa<variant_part>.
!corrigendum 4.3.2(5.4/3)
!AI-0236-1
!AI-0317-1
@ddel @xbullet<a @fa<conditional_expression> having at least one @i<dependent_>@fa<expression> that would violate this rule.>
!corrigendum 4.3.3(3/2)
!AI-0212-1
!AI-0306-1
@drepl @xindent<@fa<positional_array_aggregate>@fa<@ ::=@ >@hr @ @ @ @ (@fa<expression>,@ @fa<expression>@ {,@ @fa<expression>})@hr @ @ |@ (@fa<expression>@ {,@ @fa<expression>},@ @b<others>@ =@>@ @fa<expression>)@hr @ @ |@ (@fa<expression>@ {,@ @fa<expression>},@ @b<others>@ =@>@ <@>> @dby @xindent<@fa<positional_array_aggregate>@fa<@ ::=@ >@hr @ @ @ @ (@fa<expression>,@ @fa<expression>@ {,@ @fa<expression>})@hr @ @ |@ (@fa<expression>@ {,@ @fa<expression>},@ @b<others>@ =@>@ @fa<expression>)@hr @ @ |@ (@fa<expression>@ {,@ @fa<expression>},@ @b<others>@ =@>@ <@>)@hr @ @ |@ '['@ @fa<expression>@ {,@ @fa<expression>}[,@ @b<others>@ =@>@ @fa<expression>]@ ']'@hr @ @ |@ '['@ @fa<expression>@ {,@ @fa<expression>},@ @b<others>@ =@>@ <@>@ ']'>
@xindent<@fa<null_array_aggregate>@fa<@ ::=@ >'['@ ']'>
!corrigendum 4.3.3(4)
!AI-0127-1
!AI-0212-1
@drepl @xindent<@fa<named_array_aggregate>@fa<@ ::=@ >@hr @ @ @ @ (@fa<array_component_association>@ {,@ @fa<array_component_association>})> @dby @xindent<@fa<named_array_aggregate>@fa<@ ::=@ >@hr @ @ @ @ (@fa<array_component_association_list>)@hr @ @ |@ '['@ @fa<array_component_association_list>@ ']'>
@xindent<@fa<array_component_association_list>@fa<@ ::=@ >@hr @ @ @ @ @fa<array_component_association>@ {,@ @fa<array_component_association>}>
!corrigendum 4.3.3(5/2)
!AI-0127-1
!AI-0212-1
@drepl @xindent<@fa<array_component_association>@fa<@ ::=@ >@hr @ @ @ @ @fa<discrete_choice_list>@ =@>@ @fa<expression>@hr @ @ |@ @fa<discrete_choice_list>@ =@>@ <@>> @dby @xindent<@fa<array_component_association>@fa<@ ::=@ >@hr @ @ @ @ @fa<discrete_choice_list>@ =@>@ @fa<expression>@hr @ @ |@ @fa<discrete_choice_list> =@> <@>@hr @ @ |@ @fa<iterated_component_association>>
@xindent<@fa<iterated_component_association>@fa<@ ::=@ >@hr @ @ @ @ @b<for> @fa<defining_identifier>@ @b<in>@ @fa<discrete_choice_list>@ =@>@ @fa<expression>@hr @ @ |@ @b<for> @fa<iterator_specification>@ =@>@ @fa<expression>>
!corrigendum 4.3.3(9)
!AI-0212-1
!AI-0306-1
@drepl An @fa<array_aggregate> of an n-dimensional array type shall be written as an n-dimensional @fa<array_aggregate>. @dby An @fa<array_aggregate> of an n-dimensional array type shall be written as an n-dimensional @fa<array_aggregate>, or as a @fa<null_array_aggregate>.
!corrigendum 4.3.3(17/3)
!AI-0061-1
!AI-0127-1
!AI-0212-1
@drepl The @fa<discrete_choice_list> of an @fa<array_component_association> is allowed to have a @fa<discrete_choice> that is a nonstatic @fa<choice_expression> or that is a @fa<subtype_indication> or @fa<range> that defines a nonstatic or null range, only if it is the single @fa<discrete_choice> of its @fa<discrete_choice_list>, and there is only one @fa<array_component_association> in the @fa<array_aggregate>. @dby The @fa<discrete_choice_list> of an @fa<array_component_association> (including an @fa<iterated_component_association>) is allowed to have a @fa<discrete_choice> that is a nonstatic @fa<choice_expression> or that is a @fa<subtype_indication> or @fa<range> that defines a nonstatic or null range, only if it is the single @fa<discrete_choice> of its @fa<discrete_choice_list>, and either there is only one @fa<array_component_association> in the enclosing @fa<array_component_association_list> or the enclosing @fa<aggregate> is an @fa<array_delta_aggregate>, not an @fa<array_aggregate>.
Either all or none of the @fa<array_component_association>s of an @fa<array_component_association_list> shall be @fa<iterated_component_association>s with an @fa<iterator_specification>.
!corrigendum 4.3.3(21)
!AI-0212-1
!AI-0250-1
!AI-0327-1
@drepl The evaluation of an @fa<array_aggregate> of a given array type proceeds in two steps: @dby For an @fa<array_aggregate> that contains only @fa<array_component_association>s that are @fa<iterated_component_association>s with @fa<iterator_specification>s, evaluation proceeds in two steps:
@xhang<@xterms<1.>Each @fa<iterator_specification> is elaborated (in an arbitrary order) and an iteration is performed solely to determine a maximum count for the number of values produced by the iteration; all of these counts are combined to determine the overall length of the array, and ultimately the limits on the bounds of the array (defined below);>
@xhang<@xterms<2.>A second iteration is performed for each of the @fa<iterator_specification>s, in the order given in the @fa<aggregate>, and for each value conditionally produced by the iteration (see 5.5 and 5.5.2), the associated @fa<expression> is evaluated, its value is converted to the component subtype of the array type, and used to define the value of the next component of the array starting at the low bound and proceeding sequentially toward the high bound. A check is made that the second iteration results in an array length no greater than the maximum determined by the first iteration; Constraint_Error is raised if this check fails.>
The evaluation of any other @fa<array_aggregate> of a given array type proceeds in two steps:
!corrigendum 4.3.3(23.1/4)
!AI-0061-1
!AI-0212-1
@dinsa Each @fa<expression> in an @fa<array_component_association> defines the value for the associated component(s). For an @fa<array_component_association> with <@>, the associated component(s) are initialized to the Default_Component_Value of the array type if this aspect has been specified for the array type; otherwise, they are initialized by default as for a stand-alone object of the component subtype (see 3.3.1). @dinst During an evaluation of the @fa<expression> of an @fa<iterated_component_association> with a @fa<discrete_choice_list>, the value of the corresponding index parameter is that of the corresponding index of the corresponding array component. During an evaluation of the @fa<expression> of an @fa<iterated_component_association> with an @fa<iterator_specification>, the value of the loop parameter of the @fa<iterator_specification> is the value produced by the iteration (as described in 5.5.2).
!corrigendum 4.3.3(26)
!AI-0212-1
!AI-0250-1
!AI-0306-1
@dinsa @xbullet<For a @fa<positional_array_aggregate> (or equivalent @fa<string_literal>) without an @b<others> choice, the lower bound is that of the corresponding index range in the applicable index constraint, if defined, or that of the corresponding index subtype, if not; in either case, the upper bound is determined from the lower bound and the number of @fa<expression>s (or the length of the @fa<string_literal>);> @dinss
@xbullet<For a @fa<null_array_aggregate>, bounds for each dimension are determined as for a @fa<positional_array_aggregate> without an @b<others> choice that has no expressions for each dimension;>
@xbullet<For a @fa<named_array_aggregate> containing only @fa<iterated_component_association>s with an @fa<iterator_specification>, the lower bound is determined as for a @fa<positional_array_aggregate> without an @b<others> choice, and the upper bound is determined from the lower bound and the total number of values produced by the second set of iterations;>
!corrigendum 4.3.3(31)
!AI-0212-1
!AI-0250-1
@dinsa The exception Constraint_Error is raised if any of the above checks fail. @dinst @s8<@i<Implementation Permissions>>
When evaluating @fa<iterated_component_association>s for an @fa<array_aggregate> that contains only @fa<iterated_component_association>s with @fa<iterator_specification>s, the first step of evaluating an @fa<iterated_component_association> can be omitted if the implementation can determine the maximum number of values by some other means.
!corrigendum 4.3.3(32/3)
!AI-0061-1
!AI-0306-1
@drepl @xindent<@s9<NOTES@hr 11 In an @fa<array_aggregate>, positional notation may only be used with two or more @fa<expression>s; a single @fa<expression> in parentheses is interpreted as a parenthesized expression. A @fa<named_array_aggregate>, such as (1 =@> X), may be used to specify an array with a single component.>> @dby @xindent<@s9<NOTES@hr 11 In an @fa<array_aggregate> delimited by parentheses, positional notation may only be used with two or more @fa<expression>s; a single @fa<expression> in parentheses is interpreted as a parenthesized expression. An @fa<array_aggregate> delimited by square brackets may be used to specify an array with a single component.>>
@xindent<@s9<12 An index parameter is a constant object (see 3.3).>>
!corrigendum 4.3.3(43)
!AI-0061-1
!AI-0312-1
@dinsa @xcode<D : Bit_Vector(M .. N) := (M .. N =@> True); --@ft<@i< see 3.6>> E : Bit_Vector(M .. N) := (@b<others> =@> True); F : String(1 .. 1) := (1 =@> 'F'); --@ft<@i< a one component aggregate: same as "F">>> @dinst @xcode<G : @b<constant> Matrix :=
(@b<for> I @b<in> 1 .. 4 =@>
(@b<for> J @b<in> 1 .. 4 =@>
(@b<if> I=J @b<then> 1.0 @b<else> 0.0))); --@ft<@i< Identity matrix>>>
@xcode<Empty_Matrix : @b<constant> Matrix := []; --@ft<@i< A matrix without elements>>>
!corrigendum 4.3.4(0)
!AI-0127-1
!AI-0212-1
!AI-0324-1
!AI-0379-1
!AI-0381-1
!AI-0386-1
!AI-0429-1
@dinsc Evaluating a (record or array) delta aggregate yields a composite value that starts with a copy of another value of the same type and then assigns to some (but typically not all) components of the copy.
@s8<@i<Syntax>>
@xindent<@fa<delta_aggregate>@fa<@ ::=@ >@fa<record_delta_aggregate>@ |@ @fa<array_delta_aggregate>>
@xindent<@fa<record_delta_aggregate>@fa<@ ::=@ >@hr @ @ @ @ (@i<base_>@fa<expression>@ @b<with delta>@ @fa<record_component_association_list>)>
@xindent<@fa<array_delta_aggregate>@fa<@ ::=@ >@hr @ @ @ @ (@i<base_>@fa<expression>@ @b<with delta>@ @fa<array_component_association_list>)@hr @ @ |@ '['@ @i<base_>@fa<expression>@ @b<with delta>@ @fa<array_component_association_list>@ ']'>
@s8<@i<Name Resolution Rules>>
The expected type for a @fa<record_delta_aggregate> shall be a single descendant of a record type or record extension.
The expected type for an @fa<array_delta_aggregate> shall be a single array type.
The expected type for the @i<base_>@fa<expression> of any @fa<delta_aggregate> is the type of the enclosing @fa<delta_aggregate>.
The Name Resolution Rules and Legality Rules for each @fa<record_component_association> of a @fa<record_delta_aggregate> are as defined in 4.3.1.
For an @fa<array_delta_aggregate>, the expected type for each @fa<discrete_choice> in an @fa<array_component_association> is the index type of the type of the @fa<delta_aggregate>.
The expected type of the @fa<expression> in an @fa<array_component_association> is defined as for an @fa<array_component_association> occurring within an @fa<array_aggregate> of the type of the @fa<delta_aggregate>.
@s8<@i<Legality Rules>>
For an @fa<array_delta_aggregate>, the @fa<array_component_association> shall not use the box symbol <@>, and the @fa<discrete_choice> shall not be @b<others>.
For an @fa<array_delta_aggregate>, the dimensionality of the type of the @fa<delta_aggregate> shall be 1.
For an @fa<array_delta_aggregate>, the @i<base_>@fa<expression> and each @fa<expression> in every @fa<array_component_association> shall be of a nonlimited type.
@s8<@i<Dynamic Semantics>>
The evaluation of a @fa<delta_aggregate> begins with the evaluation of the @i<base_>@fa<expression> of the @fa<delta_aggregate>; then that value is used to create and initialize the anonymous object of the @fa<aggregate>. The bounds of the anonymous object of an @fa<array_delta_aggregate> and the discriminants (if any) of the anonymous object of a @fa<record_delta_aggregate> are those of the @i<base_>@fa<expression>. If a @fa<record_delta_aggregate> is of a specific tagged type, its tag is that of the specific type; if it is of a class-wide type, its tag is that of the @i<base_>@fa<expression>.
For a @fa<record_delta_aggregate>, for each component associated with each @fa<record_component_association> (in an unspecified order):
@xbullet<if the associated component belongs to a @fa<variant>, a check is
made that the values of the discriminants are such that the anonymous object has this component. The exception Constraint_Error is raised if this check fails.>
@xbullet<the @fa<expression> of the @fa<record_component_association> is
evaluated, converted to the nominal subtype of the associated component, and assigned to the component of the anonymous object.>
For an @fa<array_delta_aggregate>, for each @fa<discrete_choice> of each @fa<array_component_association> (in the order given in the enclosing @fa<discrete_choice_list> and @fa<array_component_association_list>, respectively) the @fa<discrete_choice> is evaluated; for each represented index value (in ascending order, if the @fa<discrete_choice> represents a range):
@xbullet<the index value is converted to the index type of the array type.>
@xbullet<a check is made that the index value belongs to the index range of
the anonymous object of the @fa<aggregate>; Constraint_Error is raised if this check fails.>
@xbullet<the component @fa<expression> is evaluated, converted to the array
component subtype, and assigned to the component of the anonymous object identified by the index value.>
@s8<@i<Examples>>
@i<Examples of use of delta aggregates in a postcondition:>
@xcode<@b<procedure> Twelfth (D : @b<in out> Date) --@ft<@i< see 3.8 for type Date>>
@b<with> Post =@> D = (D'Old @b<with delta> Day =@> 12);>
@xcode<@b<procedure> The_Answer (V : @b<in out> Vector;
A, B : @b<in> Integer) --@ft<@i< see 3.6 for type Vector>> @b<with> Post =@> V = (V'Old @b<with delta> A .. B =@> 42.0, V'First =@> 0.0);>
@i<Examples where the base expression is nontrivial:>
@xcode<New_Cell : Cell := (Min_Cell (Head) @b<with delta> Value =@> 42);
--@ft<@i< see 3.10.1 for Cell and Head; 6.1 for Min_Cell>>>
@xcode<A1 : Vector := ((0 =@> 1.0, 1 =@> 2.0, 2 =@> 3.0)
@b<with delta> Integer(Random * 2.0) =@> 14.2); --@ft<@i< see 3.6 for declaration of type Vector>> --@ft<@i< see 6.1 for declaration of Random>>>
@xcode<Tomorrow := ((Yesterday @b<with delta> Day =@> 12)
@b<with delta> Month =@> April); --@ft<@i< see 3.8>>>
@i<Example where the base expression is class-wide:>
@xcode<@b<function> Translate (P : Point'Class; X, Y : Real) @b<return> Point'Class @b<is>
(P @b<with delta> X =@> P.X + X,
Y =@> P.Y + Y); --@ft<@i< see 3.9 for declaration of type Point>>>
!corrigendum 4.3.5(0)
!AI-0212-1
!AI-0250-1
!AI-0312-1
!AI-0327-1
!AI-0388-1
!AI-0403-1
!AI-0418-1
!AI-0427-1
!AI-0429-1
!AI-0430-1
@dinsc In a @fa<container_aggregate>, values are specified for elements of a container; for a @fa<positional_container_aggregate>, the elements are given sequentially; for a @fa<named_container_aggregate>, the elements are specified by a sequence of key/value pairs, or using an iterator. The Aggregate aspect of the type of the @fa<aggregate> determines how the elements are combined to form the container.
For a type other than an array type, the following type-related operational aspect may be specified:
@xhang<@xterm<Aggregate>This aspect is an @fa<aggregate> of the form:>
@xindent<@ @ @ (Empty =@> @fa<name>[,@hr @ @ @ @ Add_Named =@> @i<procedure_>@fa<name>][,@hr @ @ @ @ Add_Unnamed =@> @i<procedure_>@fa<name>][,@hr @ @ @ @ New_Indexed =@> @i<function_>@fa<name>,@hr @ @ @ @ Assign_Indexed =@> @i<procedure_>@fa<name>])>
@xindent<The type for which this aspect is specified is known as the @i<container type> of the Aggregate aspect. A @i<procedure_>@fa<name> shall be specified for at least one of Add_Named, Add_Unnamed, or Assign_Indexed. If Add_Named is specified, neither Add_Unnamed nor Assign_Indexed shall be specified. Either both or neither of New_Indexed and Assign_Indexed shall be specified.>
@s8<@i<Name Resolution Rules>>
The @fa<name> specified for Empty for an Aggregate aspect shall denote a constant of the container type, or denote exactly one function with a result type of the container type that has no parameters, or that has one @b<in> parameter of a signed integer type.
The @i<procedure_>@fa<name> specified for Add_Unnamed for an Aggregate aspect shall denote a procedure that has two parameters, the first an @b<in out> parameter of the container type, and the second an @b<in> parameter of some nonlimited type, called the @i<element type> of the container type.
The @i<function_>@fa<name> specified for New_Indexed for an Aggregate aspect shall denote a function with a result type of the container type, and two parameters of the same discrete type, with that type being the @i<key type> of the container type.
The @i<procedure_>@fa<name> specified for Add_Named or Assign_Indexed for an Aggregate aspect shall denote a procedure that has three parameters, the first an @b<in out> parameter of the container type, the second an @b<in> parameter of a nonlimited type (the @i<key type> of the container type), and the third, an @b<in> parameter of a nonlimited type that is called the @i<element type> of the container type.
@s8<@i<Legality Rules>>
If the container type of an Aggregate aspect is a private type, the full type of the container type shall not be an array type. If the container type is limited, the name specified for Empty shall denote a function rather than a constant object.
For an Aggregate aspect, the key type of Assign_Indexed shall be the same type as that of the parameters of New_Indexed. Additionally, if both Add_Unnamed and Assign_Indexed are specified, the final parameters shall be of the same type @emdash the element type of the container type.
@s8<@i<Static Semantics>>
The Aggregate aspect is nonoverridable (see 13.1.1).
@s8<@i<Syntax>>
@xindent<@fa<container_aggregate>@fa<@ ::=@ >@hr @ @ @ @ @fa<null_container_aggregate>@hr @ @ |@ @fa<positional_container_aggregate>@hr @ @ |@ @fa<named_container_aggregate>>
@xindent<@fa<null_container_aggregate>@fa<@ ::=@ >'['@ ']'>
@xindent<@fa<positional_container_aggregate>@fa<@ ::=@ >'['@ @fa<expression>{,@ @fa<expression>}@ ']'>
@xindent<@fa<named_container_aggregate>@fa<@ ::=@ >'['@ @fa<container_element_association_list>@ ']'>
@xindent<@fa<container_element_association_list>@fa<@ ::=@ >@hr @ @ @ @ @fa<container_element_association>@ {,@ @fa<container_element_association>}>
@xindent<@fa<container_element_association>@fa<@ ::=@ >@hr @ @ @ @ @fa<key_choice_list> =@> @fa<expression>@hr @ @ |@ @fa<key_choice_list> =@> <@>@hr @ @ |@ @fa<iterated_element_association>>
@xindent<@fa<key_choice_list>@fa<@ ::=@ >@fa<key_choice>@ {'|'@ @fa<key_choice>}>
@xindent<@fa<key_choice>@fa<@ ::=@ >@i<key_>@fa<expression>@ |@ @fa<discrete_range>>
@xindent<@fa<iterated_element_association>@fa<@ ::=@ >@hr @ @ @ @ @b<for>@ @fa<loop_parameter_specification>[@ @b<use>@ @i<key_>@fa<expression>]@ =@>@ @fa<expression>@hr @ @ |@ @b<for>@ @fa<iterator_specification>[@ @b<use>@ @i<key_>@fa<expression>]@ =@>@ @fa<expression>>
@s8<@i<Name Resolution Rules>>
The expected type for a @fa<container_aggregate> shall be a type for which the Aggregate aspect has been specified. The expected type for each @fa<expression> of a @fa<container_aggregate> is the element type of the expected type.
The expected type for a @i<key_>@fa<expression>, or a @fa<discrete_range> of a @fa<key_choice>, is the key type of the expected type of the @fa<aggregate>.
@s8<@i<Legality Rules>>
The expected type for a @fa<positional_container_aggregate> shall have an Aggregate aspect that includes a specification for an Add_Unnamed procedure or an Assign_Indexed procedure. The expected type for a @fa<named_container_aggregate> that contains one or more @fa<iterated_element_association>s with a @i<key_>@fa<expression> shall have an Aggregate aspect that includes a specification for the Add_Named procedure. The expected type for a @fa<named_container_aggregate> that contains one or more @fa<key_choice_list>s shall have an Aggregate aspect that includes a specification for the Add_Named or Assign_Indexed procedure. A @fa<null_container_aggregate> can be of any type with an Aggregate aspect.
A non-null container aggregate is called an @i<indexed aggregate> if the expected type @i<T> of the aggregate specifies an Assign_Indexed procedure in its Aggregate aspect, and either there is no Add_Unnamed procedure specified for the type, or the aggregate is a @fa<named_container_aggregate> with a @fa<container_element_association> that contains a @fa<key_choice_list> or a @fa<loop_parameter_specification>. The key type of an indexed aggregate is also called the @i<index type> of the aggregate.
A @fa<container_element_association> with a <@> rather than an @fa<expression>, or with a @fa<key_choice> that is a @fa<discrete_range>, is permitted only in an indexed aggregate.
For an @fa<iterated_element_association> without a @i<key_>@fa<expression>, if the @fa<aggregate> is an indexed aggregate or the expected type of the @fa<aggregate> specifies an Add_Named procedure in its Aggregate aspect, then the type of the loop parameter of the @fa<iterated_element_association> shall be the same as the key type of the @fa<aggregate>.
For a @fa<named_container_aggregate> that is an indexed aggregate, all @fa<container_element_association>s shall contain either a @fa<key_choice_list>, or a @fa<loop_parameter_specification> without a @i<key_>@fa<expression> or @fa<iterator_filter>. Furthermore, for such an aggregate, either:
@xbullet<all @fa<key_choice>s shall be static expressions or static ranges, and every @fa<loop_parameter_specification> shall have a @fa<discrete_subtype_definition> that defines a non-null static range, and the set of values of the index type covered by the @fa<key_choice>s and the @fa<discrete_subtype_definition>s shall form a contiguous range of values with no duplications; or>
@xbullet<there shall be exactly one @fa<container_element_association>, and if it has a @fa<key_choice_list>, the list shall have exactly one @fa<key_choice>.>
@s8<@i<Dynamic Semantics>>
The evaluation of a @fa<container_aggregate> starts by creating an anonymous object @i<A> of the expected type @i<T>, initialized as follows:
@xbullet<if the @fa<aggregate> is an indexed aggregate, from the result of a call on the New_Indexed function; the actual parameters in this call represent the lower and upper bound of the @fa<aggregate>, and are determined as follows:>
@xinbull<if the @fa<aggregate> is a @fa<positional_container_aggregate>, the lower bound is the low bound of the subtype of the key parameter of the Add_Indexed procedure, and the upper bound has a position number that is the sum of the position number of the lower bound and one less than the number of @fa<expression>s in the @fa<aggregate>;>
@xinbull<if the @fa<aggregate> is a @fa<named_container_aggregate>, the lower bound is the lowest value covered by a @fa<key_choice_list> or is the low bound of a range defined by a @fa<discrete_subtype_definition> of a @fa<loop_parameter_specification>; the upper bound is the highest value covered by a @fa<key_choice_list> or is the high bound of a range defined by a @fa<discrete_subtype_definition> of a @fa<loop_parameter_specification>.>
@xbullet<if the @fa<aggregate> is not an indexed aggregate, by assignment from the Empty constant, or from a call on the Empty function specified in the Aggregate aspect. In the case of an Empty function with a formal parameter, the actual parameter has the following value:>
@xinbull<for a @fa<null_container_aggregate>, the value zero;>
@xinbull<for a @fa<positional_container_aggregate>, the number of @fa<expression>s;>
@xinbull<for a @fa<named_container_aggregate> without an @fa<iterated_element_association>, the number of @i<key_>@fa<expression>s;>
@xinbull<for a @fa<named_container_aggregate> where every @fa<iterated_element_association> contains a @fa<loop_parameter_specification>, the total number of elements specified by all of the @fa<container_element_association>s;>
@xinbull<otherwise, to an implementation-defined value.>
The evaluation then proceeds as follows:
@xbullet<for a @fa<null_container_aggregate>, the anonymous object @i<A> is the result;>
@xbullet<for a @fa<positional_container_aggregate> of a type with a specified Add_Unnamed procedure, each @fa<expression> is evaluated in an arbitrary order, and the Add_Unnamed procedure is invoked in sequence with the anonymous object @i<A> as the first parameter and the result of evaluating each @fa<expression> as the second parameter, in the order of the @fa<expression>s;>
@xbullet<for a @fa<positional_container_aggregate> that is an indexed aggregate, each @fa<expression> is evaluated in an arbitrary order, and the Assign_Indexed procedure is invoked in sequence with the anonymous object @i<A> as the first parameter, the key value as the second parameter, computed by starting with the low bound of the subtype of the key formal parameter of the Assign_Indexed procedure and taking the successor of this value for each successive @fa<expression>, and the result of evaluating each @fa<expression> as the third parameter;>
@xbullet<for a @fa<named_container_aggregate> for a type with an Add_Named procedure in its Aggregate aspect, the @fa<container_element_association>s are evaluated in an arbitrary order:>
@xinbull<for a @fa<container_element_association> with a @fa<key_choice_list>, for each @fa<key_choice> of the list in an arbitrary order, the @fa<key_choice> is evaluated as is the @fa<expression> of the @fa<container_element_association> (in an arbitrary order), and the Add_Named procedure is invoked once for each value covered by the @fa<key_choice>, with the anonymous object @i<A> as the first parameter, the value from the @fa<key_choice> as the second parameter, and the result of evaluating the @fa<expression> as the third parameter;>
@xinbull<for a @fa<container_element_association> with an @fa<iterated_element_association>, first the @fa<iterated_element_association> is elaborated, then an iteration is performed, and for each value conditionally produced by the iteration (see 5.5 and 5.5.2) the Add_Named procedure is invoked with the anonymous object @i<A> as the first parameter, the result of evaluating the @fa<expression> as the third parameter, and:>
@xI2bull<if there is a @i<key_>@fa<expression>, the result of evaluating the @i<key_>@fa<expression> as the second parameter;>
@XI2Bull<otherwise, with the loop parameter as the second parameter;>
@xbullet<for a @fa<named_container_aggregate> that is an indexed aggregate, the evaluation proceeds as above for the case of Add_Named, but with the Assign_Indexed procedure being invoked instead of Add_Named; in the case of a @fa<container_element_association> with a <@> rather than an @fa<expression>, the corresponding call on Assign_Indexed is not performed, leaving the component as it was upon return from the New_Indexed function;>
@xbullet<for any other @fa<named_container_aggregate>, the @fa<container_element_association>s (which are necessarily @fa<iterated_element_association>s) are evaluated in the order given; each such evaluation comprises two steps:>
@xhang<@xterms<1.>the @fa<iterated_element_association> is elaborated;>
@xhang<@xterms<2.>an iteration is performed, and for each value conditionally produced by the iteration (see 5.5 and 5.5.2) the Add_Unnamed procedure is invoked, with the anonymous object @i<A> as the first parameter and the result of evaluating the @fa<expression> as the second parameter.>
@s8<@i<Examples>>
@i<Examples of specifying the Aggregate aspect for a Set_Type, a Map_Type, and a Vector_Type:>
@xcode< -- @ft<@i<Set_Type is a set-like container type.>>
@b<type> Set_Type @b<is private>
@b<with> Aggregate =@> (Empty =@> Empty_Set,
Add_Unnamed =@> Include);
@b<function> Empty_Set @b<return> Set_Type;>
@xcode< @b<subtype> Small_Int @b<is> Integer @b<range> -1000..1000;>
@xcode< @b<procedure> Include (S : @b<in out> Set_Type; N : @b<in> Small_Int);>
@xcode< -- @ft<@i<Map_Type is a map-like container type.>>
@b<type> Map_Type @b<is private>
@b<with> Aggregate =@> (Empty =@> Empty_Map,
Add_Named =@> Add_To_Map);>
@xcode< @b<procedure> Add_To_Map (M : @b<in out> Map_Type;
Key : @b<in> Integer; Value : @b<in> String);>
@xcode< Empty_Map : @b<constant> Map_Type;>
@xcode< -- @ft<@i<Vector_Type is an extensible array-like container type.>>
@b<type> Vector_Type @b<is private>
@b<with> Aggregate =@> (Empty =@> Empty_Vector,
Add_Unnamed =@> Append_One, New_Indexed =@> New_Vector, Assign_Indexed =@> Assign_Element);>
@xcode< @b<function> Empty_Vector (Capacity : Integer := 0) @b<return> Vector_Type;>
@xcode< @b<procedure> Append_One (V : @b<in out> Vector_Type; New_Item : @b<in> String);>
@xcode< @b<procedure> Assign_Element (V : @b<in out> Vector_Type;
Index : @b<in> Positive; Item : @b<in> String);>
@xcode< @b<function> New_Vector (First, Last : Positive) @b<return> Vector_Type
@b<with> Pre =@> First = Positive'First; -- @ft<@i<Vectors are always indexed starting at the>> -- @ft<@i<lower bound of their index subtype.>>>
@xcode<-- @ft<@i<Private part not shown.>>>
@i<Examples of container aggregates for Set_Type, Map_Type, and Vector_Type:>
@xcode<-- @ft<@i<Example aggregates using Set_Type.>> S : Set_Type;>
@xcode<-- @ft<@i<Assign the empty set to S:>> S := [];>
@xcode<-- @ft<@i<Is equivalent to:>> S := Empty_Set;>
@xcode<-- @ft<@i<A positional set aggregate:>> S := [1, 2];>
@xcode<-- @ft<@i<Is equivalent to:>> S := Empty_Set; Include (S, 1); Include (S, 2);>
@xcode<-- @ft<@i<A set aggregate with an >>@fa<iterated_element_association>@ft<@i<:>> S := [@b<for> Item @b<in> 1 .. 5 =@> Item * 2];>
@xcode<-- @ft<@i<Is equivalent to:>> S := Empty_Set; @b<for> Item @b<in> 1 .. 5 @b<loop>
Include (S, Item * 2);
@b<end loop>;>
@xcode<-- @ft<@i<A set aggregate consisting of two >>@fa<iterated_element_association>@ft<@i<s:>> S := [@b<for> Item @b<in> 1 .. 5 =@> Item,
@b<for> Item @b<in> 1 .. 5 =@> -Item];>
@xcode<-- @ft<@i<Is equivalent (assuming set semantics) to:>> S := Empty_Set; @b<for> Item @b<in> 1 .. 5 @b<loop>
Include (S, Item);
@b<end loop>; @b<for> Item @b<in> -5 .. -1 @b<loop>
Include (S, Item);
@b<end loop>;>
@xcode<-- @ft<@i<Example aggregates using Map_Type.>> M : Map_Type;>
@xcode<-- @ft<@i<A simple named map aggregate:>> M := [12 =@> "house", 14 =@> "beige"];>
@xcode<-- @ft<@i<Is equivalent to:>> M := Empty_Map; Add_To_Map (M, 12, "house"); Add_To_Map (M, 14, "beige");>
@xcode<-- @ft<@i<Define a table of pairs:>> @b<type> Pair @b<is record>
Key : Integer; Value : @b<access constant> String;
@b<end record>;>
@xcode<Table : @b<constant array>(Positive @b<range> <@>) @b<of> Pair :=
[(Key =@> 33, Value =@> @b<new> String'("a nice string")),
(Key =@> 44, Value =@> @b<new> String'("an even better string"))];>
@xcode<-- @ft<@i<A map aggregate using an >>@fa<iterated_element_association> -- @ft<@i<and a key_>>@fa<expression>@ft<@i<, built from from a table of key/value pairs:>> M := [@b<for> P @b<of> Table @b<use> P.Key =@> P.Value.@b<all>];>
@xcode<-- @ft<@i<Is equivalent to:>> M := Empty_Map; @b<for> P @b<of> Table @b<loop>
Add_To_Map (M, P.Key, P.Value.@b<all>);
@b<end loop>;>
@xcode<-- @ft<@i<Create an image table for an array of integers:>> Keys : @b<constant array>(Positive @b<range> <@>) @b<of> Integer := [2, 3, 5, 7, 11];>
@xcode<-- @ft<@i<A map aggregate where the values produced by the>> -- @fa<iterated_element_association>@ft<@i< are of the same type as the key>> -- @ft<@i<(eliminating the need for a separate key_>>@fa<expression>@ft<@i<):>> M := [@b<for> Key @b<of> Keys =@> Integer'Image (Key)];>
@xcode<-- @ft<@i<Is equivalent to:>> M := Empty_Map; @b<for> Key @b<of> Keys @b<loop>
Add_To_Map (M, Key, Integer'Image (Key));
@b<end loop>;>
@xcode<-- @ft<@i<Example aggregates using Vector_Type.>> V : Vector_Type;>
@xcode<-- @ft<@i<A positional vector aggregate:>> V := ["abc", "def"];>
@xcode<-- @ft<@i<Is equivalent to:>> V := Empty_Vector (2); Append_One (V, "abc"); Append_One (V, "def");>
@xcode<-- @ft<@i<An indexed vector aggregate:>> V := [1 =@> "this", 2 =@> "is", 3 =@> "a", 4 =@> "test"];>
@xcode<-- @ft<@i<Is equivalent to:>> V := New_Vector (1, 4); Assign_Element (V, 1, "this"); Assign_Element (V, 2, "is"); Assign_Element (V, 3, "a"); Assign_Element (V, 4, "test");>
!corrigendum 4.5.2(37)
!AI-0178-1
!AI-0425-1
@drepl @xcode<"" < "A" @b<and> "A" < "Aa" --@ft<@i< True>> "Aa" < "B" @b<and> "A" < "A " --@ft<@i< True>>> @dby @xcode<A_String = "A" --@ft<@i< True (see 3.3.1)>> "" < A_String @b<and> A_String < "Aa" --@ft<@i< True>> A_String < "Bb" @b<and> A_String < "A " --@ft<@i< True>>>
!corrigendum 4.5.7(21/3)
!AI-0312-1
!AI-0429-1
@dinsa For the evaluation of a @fa<case_expression>, the @i<selecting_>@fa<expression> is first evaluated. If the value of the @i<selecting_>@fa<expression> is covered by the @fa<discrete_choice_list> of some @fa<case_expression_alternative>, then the @i<dependent_>@fa<expression> of the @fa<case_expression_alternative> is evaluated, converted to the type of the @fa<case_expression>, and the resulting value is the value of the @fa<case_expression>. Otherwise (the value is not covered by any @fa<discrete_choice_list>, perhaps due to being outside the base range), Constraint_Error is raised. @dinss @s8<@i<Examples>>
@i<Example of use of an> @fa<if_expression>@i<:>
@xcode<Put_Line ("Casey is " &
(@b<if> Casey.Sex = M @b<then> "Male" @b<else> "Female")); --@ft<@i< see 3.10.1>>>
@i<Example of use of a> @fa<case_expression>@i<:>
@xcode<@b<function> Card_Color (Card : Suit) @b<return> Color @b<is> --@ft<@i< see 3.5.1>>
(@b<case> Card @b<is>
@b<when> Clubs | Spades =@> Black, @b<when> Hearts | Diamonds =@> Red);>
!corrigendum 4.5.8(12/3)
!AI-0429-1
!AI-0430-1
@drepl The assertion that a positive number is composite (as opposed to prime) can be written: @dby @i<Example of use of a quantified expression as an assertion that a positive number N is composite (as opposed to prime):>
!corrigendum 4.5.9(0)
!AI-0236-1
!AI-0317-1
!AI-0429-1
@dinsc Declare expressions provide a way to declare local constants and object renamings in an expression context.
@s8<@i<Syntax>>
@xindent<@fa<declare_expression>@fa<@ ::=@ >@hr @ @ @ @ @b<declare> {@fa<declare_item>}@hr @ @ @ @ @b<begin> @i<body_>@fa<expression>>
@xindent<@fa<declare_item>@fa<@ ::=@ >@fa<object_declaration>@ |@ @fa<object_renaming_declaration>>
Wherever the Syntax Rules allow an @fa<expression>, a @fa<declare_expression> may be used in place of the @fa<expression>, so long as it is immediately surrounded by parentheses.
@s8<@i<Legality Rules>>
A @fa<declare_item> that is an @fa<object_declaration> shall declare a constant of a nonlimited type.
A @fa<declare_item> that is an @fa<object_renaming_declaration> (see 8.5.1) shall not rename an object of a limited type if any operative constituent of the @i<object_>@fa<name> is a value conversion or is newly constructed (see 4.4).
The following are not allowed within a @fa<declare_expression>: a declaration containing the reserved word @b<aliased>; the @fa<attribute_designator> Access or Unchecked_Access; or an anonymous access type.
@s8<@i<Name Resolution Rules>>
If a @fa<declare_expression> is expected to be of a type @i<T>, then the @i<body_>@fa<expression> is expected to be of type @i<T>. Similarly, if a @fa<declare_expression> is expected to be of some class of types, then the @i<body_>@fa<expression> is subject to the same expectation. If a @fa<declare_expression> shall resolve to be of a type @i<T>, then the @i<body_>@fa<expression> shall resolve to be of type @i<T>.
The type of a @fa<declare_expression> is the type of the @i<body_>@fa<expression>.
@s8<@i<Dynamic Semantics>>
For the evaluation of a @fa<declare_expression>, the @fa<declare_item>s are elaborated in order, and then the @i<body_>@fa<expression> is evaluated. The value of the @fa<declare_expression> is that of the @i<body_>@fa<expression>.
@s8<@i<Examples>>
@i<Example of use of a declare expression as a replacement postcondition for Ada.Containers.Vectors."&" (see A.18.2):>
@xcode<@b<with> Post =@>
(@b<declare>
Result @b<renames> Vectors."&"'Result; Length : @b<constant> Count_Type := Left.Length + Right.Length;
@b<begin>
Result.Length = Length @b<and then> @b<not> Tampering_With_Elements_Prohibited (Result) @b<and then> @b<not> Tampering_With_Cursors_Prohibited (Result) @b<and then> Result.Capacity @>= Length)>
!corrigendum 4.5.10(0)
!AI-0242-1
!AI-0250-1
!AI-0262-1
!AI-0327-1
!AI-0348-1
!AI-0355-2
!AI-0379-1
!AI-0427-1
!AI-0429-1
@dinsc
Reduction expressions provide a way to map or transform a collection of values into a new set of values, and then summarize the values produced by applying an operation to reduce the set to a single value result. A reduction expression is represented as an @fa<attribute_reference> of the reduction attributes Reduce or Parallel_Reduce.
@s8<@i<Syntax>>
@xindent<@fa<reduction_attribute_reference>@fa<@ ::=@ >@hr @ @ @ @ @fa<value_sequence>'@fa<reduction_attribute_designator>@hr @ @ |@ @fa<prefix>'@fa<reduction_attribute_designator>>
@xindent<@fa<value_sequence>@fa<@ ::=@ >@hr @ @ @ @ '['@ [@b<parallel>[(@fa<chunk_specification>)]@ [@fa<aspect_specification>]]@hr @ @ @ @ @ @ @ @ @fa<iterated_element_association>@ ']'>
@xindent<@fa<reduction_attribute_designator>@fa<@ ::=@ >@i<reduction_>@fa<identifier>(@fa<reduction_specification>)>
@xindent<@fa<reduction_specification>@fa<@ ::=@ >@i<reducer_>@fa<name>,@ @i<initial_value_>@fa<expression>>
The @fa<iterated_element_association> of a @fa<value_sequence> shall not have a @i<key_>@fa<expression>, nor shall it have a @fa<loop_parameter_specification> that has the reserved word @b<reverse>.
The @fa<chunk_specification>, if any, of a @fa<value_sequence> shall be an @i<integer_>@fa<simple_expression>.
@s8<@i<Name Resolution Rules>>
The expected type for a @fa<reduction_attribute_reference> shall be a single nonlimited type.
In the remainder of this subclause, we will refer to nonlimited subtypes @i<Value_Type> and @i<Accum_Type> of a @fa<reduction_attribute_reference>. These subtypes and interpretations of the @fa<name>s and @fa<expression>s of a @fa<reduction_attribute_reference> are determined by the following rules:
@xbullet<@i<Accum_Type> is a subtype of the expected type of the @fa<reduction_attribute_reference>.>
@xbullet<A @i<reducer subprogram> is subtype conformant with one of the following specifications:>
@xcode< @b<function> Reducer(Accumulator : @i<Accum_Type>;
Value : @i<Value_Type>) @b<return> @i<Accum_Type>;>
@xcode< @b<procedure> Reducer(Accumulator : @b<in out> @i<Accum_Type>;
Value : @b<in> @i<Value_Type>);>
@xbullet<The @i<reducer_>@fa<name> of a @fa<reduction_specification> denotes a reducer subprogram.>
@xbullet<The expected type of an @i<initial_value_>@fa<expression> of a @fa<reduction_specification> is that of subtype @i<Accum_Type>.>
@xbullet<The expected type of the @fa<expression> of the @fa<iterated_element_association> of a @fa<value_sequence> is that of subtype @i<Value_Type>.>
@s8<@i<Legality Rules>>
If the @fa<reduction_attribute_reference> has a @fa<value_sequence> with the reserved word @b<parallel>, the subtypes @i<Accum_Type> and @i<Value_Type> shall statically match.
If the @fa<identifier> of a @fa<reduction_attribute_designator> is Parallel_Reduce, the subtypes @i<Accum_Type> and @i<Value_Type> shall statically match.
@s8<@i<Static Semantics>>
A @fa<reduction_attribute_reference> denotes a value, with its nominal subtype being the subtype of the first parameter of the subprogram denoted by the @i<reducer_>@fa<name>.
@s8<@i<Dynamic Semantics>>
For the evaluation of a @fa<value_sequence>, the @fa<iterated_element_association>, the @fa<chunk_specification>, and the @fa<aspect_specification>, if any, are elaborated in an arbitrary order. Next an iteration is performed, and for each value conditionally produced by the iteration (see 5.5 and 5.5.2), the associated @fa<expression> is evaluated with the loop parameter having this value, which produces a result that is converted to Value_Type and is used to define the next value in the sequence.
If the @fa<value_sequence> does not have the reserved word @b<parallel>, it is produced as a single sequence of values by a single logical thread of control. If the reserved word @b<parallel> is present in the @fa<value_sequence>, the enclosing @fa<reduction_attribute_reference> is a parallel construct, and the sequence of values is generated by a parallel iteration (as defined in 5.5, 5.5.1, and 5.5.2), as a set of non-empty, non-overlapping contiguous chunks (@i<subsequences>) with one logical thread of control (see clause 9) associated with each subsequence. If there is a @fa<chunk_specification>, it determines the maximum number of chunks, as defined in 5.5; otherwise the maximum number of chunks is implementation defined.
For a @fa<value_sequence> V, the following attribute is defined:
@xhang<@xterm<V'Reduce(Reducer, Initial_Value)> This attribute represents a @i<reduction expression>, and is in the form of a @fa<reduction_attribute_reference>.>
@xindent<The evaluation of a use of this attribute begins by evaluating the parts of the @fa<reduction_attribute_designator> (the @i<reducer_>@fa<name> Reducer and the @i<initial_value_>@fa<expression> Initial_Value), in an arbitrary order. It then initializes the @i<accumulator> of the reduction expression to the value of the @i<initial_value_>@fa<expression> (the @i<initial value>). The @fa<value_sequence> V is then evaluated.>
@xindent<If the @fa<value_sequence> does not have the reserved word @b<parallel>, each value of the @fa<value_sequence> is passed, in order, as the second (Value) parameter to a call on Reducer, with the first (Accumulator) parameter being the prior value of the accumulator, saving the result as the new value of the accumulator. The reduction expression yields the final value of the accumulator.>
@xindent<If the reserved word @b<parallel> is present in a @fa<value_sequence>, then the (parallel) reduction expression is a parallel construct and the sequence has been partitioned into one or more subsequences (see above) each with its own separate logical thread of control.>
@xindent<Each logical thread of control creates a local accumulator for processing its subsequence. The accumulator for a subsequence is initialized to the first value of the subsequence, and calls on Reducer start with the second value of the subsequence (if any). The result for the subsequence is the final value of its local accumulator.>
@xindent<After all logical threads of control of a parallel reduction expression have completed, Reducer is called for each subsequence, in the original sequence order, passing the local accumulator for that subsequence as the second (Value) parameter, and the overall accumulator (initialized above to the initial value) as the first (Accumulator) parameter, with the result saved back in the overall accumulator. The parallel reduction expression yields the final value of the overall accumulator.>
@xindent<If the evaluation of the @fa<value_sequence> yields an empty sequence of values, the reduction expression yields the initial value.>
@xindent<If an exception is propagated by one of the calls on Reducer, that exception is propagated from the reduction expression. If different exceptions are propagated in different logical threads of control, one is chosen arbitrarily to be propagated from the reduction expression as a whole.>
For a @fa<prefix> X of an array type (after any implicit dereference), or that denotes an iterable container object (see 5.5.1), the following attributes are defined:
@xhang<@xterm<X'Reduce(Reducer, Initial_Value)>X'Reduce
is a reduction expression that yields a result equivalent to replacing the @fa<prefix> of the attribute with the @fa<value_sequence>:>
@xcode< [@b<for> Item @b<of> X =@> Item]>
@xhang<@xterm<X'Parallel_Reduce(Reducer, Initial_Value)>X'Parallel_Reduce
is a reduction expression that yields a result equivalent to replacing the attribute @fa<identifier> with Reduce and the @fa<prefix> of the attribute with the @fa<value_sequence>:>
@xcode< [@b<parallel for> Item @b<of> X =@> Item]>
@s8<@i<Bounded (Run-Time) Errors>>
For a parallel reduction expression, it is a bounded error if the reducer subprogram is not associative. That is, for any arbitrary values of subtype @i<Value_Type> @i<A>, @i<B>, @i<C> and a reducer function @i<R>, the result of @i<R> (@i<A>, @i<R> (@i<B>, @i<C>)) should produce a result equal to @i<R> (@i<R> (@i<A>, @i<B>), @i<C>)); it is a bounded error if @i<R> does not. The possible consequences are Program_Error, or a result that does not match the equivalent sequential reduction expression due to the order of calls on the reducer subprogram being unspecified in the overall reduction. Analogous rules apply in the case of a reduction procedure.
@s8<@i<Examples>>
@i<Example of an expression function that returns its result as a reduction expression:>
@xcode<@b<function> Factorial(N : Natural) @b<return> Natural @b<is>
([@b<for> J @b<in> 1..N =@> J]'Reduce("*", 1));>
@i<Example of a reduction expression that computes the Sine of X using a Taylor expansion:>
@xcode<@b<function> Sine (X : Float; Num_Terms : Positive := 5) @b<return> Float @b<is>
([@b<for> I @b<in> 1..Num_Terms =@>
(-1.0)**(I-1) * X**(2*I-1)/Float(Factorial(2*I-1))]'Reduce("+", 0.0));>
@i<Example of a reduction expression that outputs the sum of squares:>
@xcode<Put_Line ("Sum of Squares is" &
Integer'Image([@b<for> I @b<in> 1 .. 10 =@> I**2]'Reduce("+", 0)));>
@i<Example of a reduction expression used to compute the value of Pi:>
@xcode<-- @ft<@i<See 3.5.7.>> @b<function> Pi (Number_Of_Steps : Natural := 10_000) @b<return> Real @b<is>
(1.0 / Real (Number_Of_Steps) *
[@b<for> I @b<in> 1 .. Number_Of_Steps =@>
(4.0 / (1.0 + ((Real (I) - 0.5) * (1.0 / Real (Number_Of_Steps)))**2))] 'Reduce("+", 0.0));>
@i<Example of a reduction expression used to calculate the sum of elements of an array of integers:>
@xcode<A'Reduce("+",0) -- @ft<@i<See 4.3.3.>>>
@i<Example of a reduction expression used to determine if all elements in a two-dimensional array of booleans are set to true:>
@xcode<Grid'Reduce("and", True) -- @ft<@i<See 3.6.>>>
@i<Example of a reduction expression used to calculate the minimum value of an array of integers in parallel:>
@xcode<A'Parallel_Reduce(Integer'Min, Integer'Last)>
@i<Example of a parallel reduction expression used to calculate the mean of the elements of a two-dimensional array of subtype Matrix (see 3.6) that are greater than 100.0:>
@xcode<@b<type> Accumulator @b<is record>
Sum : Real; --@ft<@i< See 3.5.7.>> Count : Integer;
@b<end record>;>
@xcode<@b<function> Accumulate (L, R : Accumulator) @b<return> Accumulator @b<is>
(Sum =@> L.Sum + R.Sum,
Count =@> L.Count + R.Count);>
@xcode<@b<function> Average_of_Values_Greater_Than_100 (M : Matrix) @b<return> Real @b<is>
(@b<declare>
Acc : @b<constant> Accumulator :=
[@b<parallel for> Val @b<of> M @b<when> Val @> 100.0 =@> (Val, 1)] 'Reduce(Accumulate, (Sum =@> 0, Count =@> 0));
@b<begin>
Acc.Sum / Real(Acc.Count));>
!corrigendum 4.6(24.21/4)
!AI-0064-2
!AI-0380-1
@dinsa @xinbull<The accessibility level of the operand type shall not be statically deeper than that of the target type. If the operand type is declared within a generic body, the target type shall be declared within the generic body.> @dinst @xinbull<If the target type is nonblocking, the operand type shall be nonblocking.>
@xinbull<If the target type has a Global aspect other than @b<in out all> or Unspecified, then each mode of the Global aspect of the operand type shall identify a subset of the variables identified by the corresponding mode of the target type Global aspect, or by the @b<in out> mode of the target type Global aspect.>
!corrigendum 4.6(51/4)
!AI-0333-1
!AI-0432-1
@drepl After conversion of the value to the target type, if the target subtype is constrained, a check is performed that the value satisfies this constraint. If the target subtype excludes null, then a check is made that the value is not null. If predicate checks are enabled for the target subtype (see 3.2.4), a check is performed that the value satisfies the predicates of the target subtype. @dby After conversion of the value to the target type, if the target subtype is constrained, a check is performed that the value satisfies this constraint. If the target subtype excludes null, then a check is made that the value is not null. If predicate checks are enabled for the target subtype (see 3.2.4), a check is performed that the value satisfies the predicates of the target subtype, unless the conversion is:
@xbullet<a view conversion that is the target of an assignment statement and is not referenced with a @fa<target_name>, or an actual parameter of mode @b<out>; or>
@xbullet<an implicit subtype conversion of an actual parameter of mode @b<out> to the nominal subtype of its formal parameter.>
!corrigendum 4.9(8)
!AI-0064-2
!AI-0368-1
@drepl @xbullet<an @fa<attribute_reference> whose @fa<prefix> statically denotes a statically constrained array object or array subtype, and whose @fa<attribute_designator> is First, Last, or Length, with an optional dimension;> @dby @xbullet<an @fa<attribute_reference> whose @fa<prefix> statically names a statically constrained array object or array subtype, and whose @fa<attribute_designator> is First, Last, or Length, with an optional dimension;>
@xbullet<an @fa<attribute_reference> whose @fa<prefix> denotes a non-generic entity that is not declared in a generic unit, and whose @fa<attribute_designator> is Nonblocking;>
!corrigendum 4.9(17)
!AI-0368-1
!AI-0373-1
@dinsa @xbullet<It denotes a @fa<renaming_declaration> with a @fa<name> that statically denotes the renamed entity.> @dinss A @fa<name> @i<statically names> an object if it: @xbullet<statically denotes the declaration of an object (possibly through one or more renames);> @xbullet<is a @fa<selected_component> whose prefix statically names an object,
there is no implicit dereference of the prefix, and the @fa<selector_name> does not denote a @fa<component_declaration> occurring within a @fa<variant_part>; or>
@xbullet<is an @fa<indexed_component> whose prefix statically names an object,
there is no implicit dereference of the prefix, the object is statically constrained, and the index expressions of the object are static and have values that are within the range of the index constraint.>
For an entity other than an object, a @fa<name> statically names an entity if the @fa<name> statically denotes the entity.
!corrigendum 4.9(20)
!AI-0201-1
!AI-0385-1
@drepl @xbullet<a predefined concatenation operator whose result type is a string type;> @dby @xbullet<a predefined concatenation operator whose result type is a string type that is not a descendant of a formal array type;>
@xbullet<a shifting or rotating function associated with a modular type declared in package Interfaces (see B.2);>
!corrigendum 4.9(24)
!AI-0201-1
!AI-0393-1
@drepl A @i<static constant> is a constant view declared by a full constant declaration or an @fa<object_renaming_declaration> with a static nominal subtype, having a value defined by a static scalar expression or by a static string expression whose value has a length not exceeding the maximum length of a @fa<string_literal> in the implementation. @dby A @i<static constant> is a constant view declared by a full constant declaration or an @fa<object_renaming_declaration> with a static nominal subtype, having a value defined by a static scalar expression or by a static string expression, and which satisfies any constraint or predicate that applies to the nominal subtype.
!corrigendum 4.9.1(2/3)
!AI-0059-1
!AI-0374-2
!AI-0427-1
@drepl A subtype @i<statically matches> another subtype of the same type if they have statically matching constraints, all predicate specifications that apply to them come from the same declarations, and, for access subtypes, either both or neither exclude null. Two anonymous access-to-object subtypes statically match if their designated subtypes statically match, and either both or neither exclude null, and either both or neither are access-to-constant. Two anonymous access-to-subprogram subtypes statically match if their designated profiles are subtype conformant, and either both or neither exclude null. @dby The Global or Global'Class aspects (see 6.1.2) of two entities @i<statically match> if both consist of a single @fa<global_aspect_definition> where each is the reserved word @b<null>, or each is of the form "@fa<global_mode> @fa<global_designator>" with each @fa<global_mode> being the same sequence of reserved words and each @fa<global_designator> being the same reserved word, or each being a @fa<global_name> that statically names the same entity.
A subtype @i<statically matches> another subtype of the same type if they have statically matching constraints, all predicate specifications that apply to them come from the same declarations, Nonblocking aspects have the same value, global aspects statically match, Object_Size (see 13.3) has been specified to have a nonconfirming value for either both or neither, and the nonconfirming values, if any, are the same, and, for access subtypes, either both or neither exclude null. Two anonymous access-to-object subtypes statically match if their designated subtypes statically match, and either both or neither exclude null, and either both or neither are access-to-constant. Two anonymous access-to-subprogram subtypes statically match if their designated profiles are subtype conformant, and either both or neither exclude null.
!corrigendum 4.10(0)
!AI-0020-1
!AI-0250-1
!AI-0315-1
!AI-0340-1
!AI-0384-2
!AI-0419-1
!AI-0425-1
!AI-0427-1
!AI-0435-1
@dinsc
An @i<image> of a value is a string representing the value in display form. The attributes Image, Wide_Image, and Wide_Wide_Image are available to produce the image of a value as a String, Wide_String, or Wide_Wide_String (respectively). User-defined images for a given type can be implemented by overriding the default implementation of the attribute Put_Image.
@s8<@i<Static Semantics>>
For every subtype S of a type T other than @i<universal_real> or @i<universal_fixed>, the following type-related operational attribute is defined:
@xhang<@xterm<S'Put_Image> S'Put_Image denotes a procedure with the following specification:>
@xcode< @b<procedure> S'Put_Image
(@ft<@i<Buffer>> : @b<in out>
Ada.Strings.Text_Buffers.Root_Buffer_Type'Class;
@ft<@i<Arg>> : @b<in> T);>
@xindent<The default implementation of S'Put_Image writes (using Wide_Wide_Put) an @i<image> of the value of @i<Arg>.>
@xindent<The Put_Image attribute may be specified for any specific type T either via an @fa<attribute_definition_clause> or via an @fa<aspect_specification> specifying the Put_Image aspect of the type.>
The behavior of the default implementation of S'Put_Image depends on the class of T.
For an untagged derived type, or a null extension, the default implementation of T'Put_Image invokes the Put_Image for its parent type on a conversion of the parameter of type T to the parent type.
For a nonderived elementary type, the implementation is equivalent to: @xcode<@b<procedure> Scalar_Type'Put_Image
(Buffer : @b<in out> Ada.Strings.Text_Buffers.Root_Buffer_Type'Class;
Arg : @b<in> Scalar_Type) @b<is>
@b<begin>
Buffer.Wide_Wide_Put (@i<<described below@>>);
@b<end> Scalar_Type'Put_Image;> where the Wide_Wide_String value written out to the text buffer is defined as follows:
@xbullet<For an integer type, the image written out is the corresponding decimal literal, without underlines, leading zeros, exponent, or trailing spaces, but with a single leading character that is either a minus sign or a space.>
@xbullet<For an enumeration type, the image written out is either the corresponding identifier in upper case or the corresponding character literal (including the two apostrophes); neither leading nor trailing spaces are included. For a @i<nongraphic character> (a value of a character type that has no enumeration literal associated with it), the value is a corresponding language-defined name in upper case (for example, the image of the nongraphic character identified as @i<nul> is @fc<"NUL"> @emdash the quotes are not part of the image).>
@xbullet<For a floating point type, the image written out is a decimal real literal best approximating the value (rounded away from zero if halfway between) with a single leading character that is either a minus sign or a space, a single digit (that is nonzero unless the value is zero), a decimal point, S'Digits-1 (see 3.5.8) digits after the decimal point (but one if S'Digits is one), an upper case E, the sign of the exponent (either + or -), and two or more digits (with leading zeros if necessary) representing the exponent. If S'Signed_Zeros is True, then the leading character is a minus sign for a negatively signed zero.>
@xbullet<For a fixed point type, the image written out is a decimal real literal best approximating the value (rounded away from zero if halfway between) with a single leading character that is either a minus sign or a space, one or more digits before the decimal point (with no redundant leading zeros), a decimal point, and S'Aft (see 3.5.10) digits after the decimal point.>
@xbullet<For an access type (named or anonymous), the image written out depends on whether the value is @b<null>. If it is @b<null>, then the image is @fc<"NULL">. Otherwise the image is a left parenthesis followed by @fc<"ACCESS">, a space, and a sequence of graphic characters, other than space or right parenthesis, representing the location of the designated object, followed by a right parenthesis, as in @fc<"(ACCESS FF0012AC)">.>
For a nonnull type extension, the default implementation of T'Put_Image depends on whether there exists a noninterface ancestor of T (other than T itself) for which the Put_Image aspect has been directly specified. If so, then T'Put_Image will generate an image based on extension aggregate syntax where the ancestor type of the extension aggregate is the nearest ancestor type whose Put_Image aspect has been specified. If no such ancestor exists, then the default implementation of T'Put_Image is the same as described below for a nonderived record type.
For a specific, nonderived composite type:
@xbullet<If the default implementation of Put_Image writes components, the order in which components are written is the same canonical order in which components of a composite type T are written out by the default implementation of T'Write. This is also the order that is used in determining the meaning of a positional aggregate of type T.>
@xbullet<For an array type T, the default implementation of T'Put_Image generates an image based on named (not positional) array aggregate syntax (with '[' and ']' as the delimiters) using calls to the Put_Image procedures of the index type(s) and the element type to generate images for values of those types.>
@xindent<The case of a null array is handled specially, using ranges for index bounds and @fc<"<@>"> as a syntactic component-value placeholder.>
@xbullet<For a record type (or, as indicated above, a type extension with no noninterface ancestor specifying Put_Image), or a protected type, the default implementation of T'Put_Image generates an image based on named (not positional) record aggregate syntax (except that for a protected type, the initial left parenthesis is followed by @fc<"PROTECTED with ">). Component names are displayed in upper case, following the rules for the image of an enumeration value. Component values are displayed via calls to the component type's Put_Image procedure.>
@xindent<The image written out for a record having no components (including any interface type) is @fc<"(NULL RECORD)">. The image written out for a componentless protected type is @fc<"(PROTECTED NULL RECORD)">. In the case of a protected type T, a call to the default implementation of T'Put_Image begins only one protected (read-only) action.>
@xbullet<For an undiscriminated task type, the default implementation of T'Put_Image generates an image of the form @fc<"(TASK <task_id_image@>)"> where <task_id_image@> is the result obtained by calling Task_Identification.Image with the id of the given task and then passing that String to Characters.Conversions.To_Wide_Wide_String.>
@xbullet<For a discriminated task type, the default implementation of T'Put_Image also includes discriminant values, as in:>
@xcode<"(TASK <task_id_image@> with D1 =@> 123, D2 =@> 456)">
For a class-wide type, the default implementation of T'Put_Image generates an image based on qualified expression syntax. Wide_Wide_Put is called with Wide_Wide_Expanded_Name of @i<Arg>'Tag. Then S'Put_Image is called, where S is the specific type identified by @i<Arg>'Tag.
T'Put_Image is the same for both the partial view and full view of T, if T has a partial view.
In the @fa<parameter_and_result_profile> for the default implementation of Put_Image, the subtype of the @i<Arg> parameter is the base subtype of @i<T> if @i<T> is a scalar type, and the first subtype otherwise. For an @fa<aspect_specification> or @fa<attribute_definition_clause> specifying Put_Image, the subprogram name shall denote a nonabstract procedure whose second parameter is either of the first subtype of @i<T>, or as an option when @i<T> is scalar, the base subtype of @i<T>.
For every subtype S of a type T, the following attributes are defined:
@xhang<@xterm<S'Wide_Wide_Image> S'Wide_Wide_Image denotes a function with the following specification:>
@xcode< @b<function> S'Wide_Wide_Image(@ft<@i<Arg>> : S'Base)
@b<return> Wide_Wide_String>
@xindent<S'Wide_Wide_Image calls S'Put_Image passing @i<Arg> (which will typically store a sequence of character values in a text buffer) and then returns the result of retrieving the contents of that buffer with function Wide_Wide_Get. The lower bound of the result is one. Any exception propagated by the call of S'Put_Image is propagated.>
@xhang<@xterm<S'Wide_Image> S'Wide_Image denotes a function with the following specification:>
@xcode< @b<function> S'Wide_Image(@ft<@i<Arg>> : S'Base)
@b<return> Wide_String>
@xindent<S'Wide_Image calls S'Put_Image passing @i<Arg> (which will typically store a sequence of character values in a text buffer) and then returns the result of retrieving the contents of that buffer with function Wide_Get. The lower bound of the result is one. Any exception propagated by the call of S'Put_Image is propagated.>
@xhang<@xterm<S'Image> S'Image denotes a function with the following specification:>
@xcode< @b<function> S'Image(@ft<@i<Arg>> : S'Base)
@b<return> String>
@xindent<S'Image calls S'Put_Image passing @i<Arg> (which will typically store a sequence of character values in a text buffer) and then returns the result of retrieving the contents of that buffer with function Get. The lower bound of the result is one. Any exception propagated by the call of S'Put_Image is propagated.>
For a @fa<prefix> X of a type T other than @i<universal_real> or @i<universal_fixed>, the following attributes are defined:
@xhang<@xterm<X'Wide_Wide_Image> X'Wide_Wide_Image denotes the result of calling function S'Wide_Wide_Image with @i<Arg> being X, where S is the nominal subtype of X.> @xhang<@xterm<X'Wide_Image> X'Wide_Image denotes the result of calling function S'Wide_Image with @i<Arg> being X, where S is the nominal subtype of X.> @xhang<@xterm<X'Image> X'Image denotes the result of calling function S'Image with @i<Arg> being X, where S is the nominal subtype of X.>
@s8<@i<Implementation Permissions>>
An implementation may transform the image generated by the default implementation of S'Put_Image for a composite subtype S in the following ways:
@xbullet<If S is a composite subtype, the leading character of the image @i<M> of a component value or index value is a space, and the immediately preceding character (if any) is an open parenthesis, open bracket, or space, then the leading space of the image @i<M> may be omitted.>
@xbullet<If S is an array subtype, the low bound of the array in each dimension equals the low bound of the corresponding index subtype, and the array value is not a null array value, then positional array aggregate syntax may be used.>
@xbullet<If S is an array subtype and the given value can be displayed using @fa<named_array_aggregate> syntax where some @fa<discrete_choice_list> identifies more than one index value by identifying a sequence of one or more ranges and values separated by vertical bars, then this image may be generated instead; this may involve the reordering of component values.>
@xbullet<Similarly, if S is a record subtype (or a discriminated type) and the given value can be displayed using named component association syntax where the length of some component_choice_list is greater than one, then this image may be generated instead; this may involve the reordering of component values.>
@xbullet<Additional spaces (Wide_Wide_Characters with position 32), and calls to the New_Line operation of a text buffer, may be inserted to improve readability of the generated image, with the spaces inserted directly or via use of the Increase_Indent and Decrease_Indent procedures.>
@xbullet<For a string type, implementations may produce an image corresponding to a string literal.>
@xbullet<For an unchecked union type, implementations may raise Program_Error or produce some recognizable image (such as "@fc<(UNCHECKED UNION)>") that does not require reading the discriminants.>
For each language-defined nonscalar type T, T'Put_Image may be specified.
@s8<@i<Implementation Requirements>>
For each language-defined container type T (that is, each of the Vector, List, Map, Set, Tree, and Holder types defined in the various children of Ada.Containers), T'Put_Image shall be specified so that T'Image produces a result consistent with array aggregate syntax (using '[' and ']' as delimiters) as follows:
@xbullet<Vector images shall be consistent with the default image of an array type with the same index and component types.>
@xbullet<Map images shall be consistent with named array aggregate syntax, using key value images in place of discrete choice names. For example, @fc<[Key1 =@> Value1, Key2 =@> Value2]>.>
@xbullet<Set, List, and Holder images shall be consistent with positional array aggregate syntax. List elements shall occur in order within an image of a list. The image of an empty holder shall be @fc<[]>.>
@xbullet<Tree images (and images of subtrees of trees) shall be consistent with positional array aggregate syntax. For example, @fc<[[1, 2], [111, 222, 333]]>.>
For each language-defined nonscalar type T that has a primitive language-defined Image function whose profile is type conformant with that of T'Image (for example, Ada.Numerics.Float_Random.State has such an Image function), T'Put_Image shall be specified so that T'Image yields the same result as that Image function.
@s8<@i<Implementation Advice>>
For each language-defined private type T, T'Image should generate an image that would be meaningful based only on the relevant public interfaces, as opposed to requiring knowledge of the implementation of the private type.
!corrigendum 5.2.1(0)
!AI-0125-3
!AI-0322-1
!AI-0379-1
!AI-0429-1
@dinsc
@@, known as the @i<target name> of an assignment statement, provides an abbreviation to avoid repetition of potentially long names in assignment statements.
@s8<@i<Syntax>>
@xindent<@fa<target_name>@fa<@ ::=@ >@@>
@s8<@i<Name Resolution Rules>>
If a @fa<target_name> occurs in an @fa<assignment_statement> @i<A>, the @i<variable_>@fa<name> @i<V> of @i<A> is a complete context. The target name is a constant view of @i<V>, having the nominal subtype of @i<V>.
@s8<@i<Legality Rules>>
A @fa<target_name> shall appear only in the @fa<expression> of an @fa<assignment_statement>.
@s8<@i<Dynamic Semantics>>
For the execution of an @fa<assignment_statement> with one or more @fa<target_name>s appearing in its @fa<expression>, the @i<variable_>@fa<name> @i<V> of the @fa<assignment_statement> is evaluated first to determine the object denoted by @i<V>, and then the @fa<expression> of the @fa<assignment_statement> is evaluated with the evaluation of each @fa<target_name> yielding a constant view of the the target whose properties are otherwise identical to those of the view provided by @i<V>. The remainder of the execution of the @fa<assignment_statement> is as given in subclause 5.2.
@s8<@i<Examples>>
@i<Examples of the use of target name symbols:>
@xcode<Board(1, 1) := @@ + 1.0; -- @ft<@i<An abbreviation for Board(1, 1) := Board(1, 1) + 1.0;>>
-- @ft<@i<(Board is declared in 3.6.1).>>>
@xcode<My_Complex_Array : @b<array> (1 .. Max) @b<of> Complex; -- @ft<@i<See 3.3.2, 3.8.>> ... -- @ft<@i<Square the element in the Count (see 3.3.1) position:>> My_Complex_Array (Count) := (Re =@> @@.Re**2 - @@.Im**2,
Im =@> 2.0 @@.Re @@.Im); -- @ft<@i<A target_name can be used multiple times and as a prefix if needed.>>>
!corrigendum 5.5(3/3)
!AI-0119-1
!AI-0189-1
!AI-0251-1
!AI-0266-1
!AI-0326-2
!AI-0355-2
@drepl @xindent<@fa<iteration_scheme>@fa<@ ::=@ >@b<while>@ @fa<condition>@hr @ @ |@ @b<for>@ @fa<loop_parameter_specification>@hr @ @ |@ @b<for>@ @fa<iterator_specification>> @dby @xindent<@fa<iteration_scheme>@fa<@ ::=@ >@b<while>@ @fa<condition>@hr @ @ |@ @b<for>@ @fa<loop_parameter_specification>@hr @ @ |@ @b<for>@ @fa<iterator_specification>@hr @ @ |@ [@b<parallel>@ [@fa<aspect_specification>]]@hr @ @ @ @ @b<for>@ @fa<procedural_iterator>@hr @ @ |@ @b<parallel>@ [(@fa<chunk_specification>)]@ [@fa<aspect_specification>]@hr @ @ @ @ @b<for>@ @fa<loop_parameter_specification>@hr @ @ |@ @b<parallel>@ [(@fa<chunk_specification>)]@ [@fa<aspect_specification>]@hr @ @ @ @ @b<for>@ @fa<iterator_specification>>
@xindent<@fa<chunk_specification>@fa<@ ::=@ >@hr @ @ @ @ @i<integer_>@fa<simple_expression>@hr @ @ |@ @fa<defining_identifier>@ @b<in>@ @fa<discrete_subtype_definition>>
!corrigendum 5.5(5)
!AI-0119-1
!AI-0251-1
@dinsa If a @fa<loop_statement> has a @i<loop_>@fa<statement_identifier>, then the @fa<identifier> shall be repeated after the @b<end loop>; otherwise, there shall not be an @fa<identifier> after the @fa<end loop>.
@dinst An @fa<iteration_scheme> that begins with the reserved word @b<parallel> shall not have the reserved word @b<reverse> in its @fa<loop_parameter_specification>.
@s8<@i<Name Resolution Rules>>
In a @fa<chunk_specification> that is an @i<integer_>@fa<simple_expression>, the @i<integer_>@fa<simple_expression> is expected to be of any integer type.
!corrigendum 5.5(6)
!AI-0061-1
!AI-0251-1
@drepl A @fa<loop_parameter_specification> declares a @i<loop parameter>, which is an object whose subtype is that defined by the @fa<discrete_subtype_definition>. @dby A @fa<loop_parameter_specification> declares a @i<loop parameter>, which is an object whose subtype (and nominal subtype) is that defined by the @fa<discrete_subtype_definition>.
In a @fa<chunk_specification> that has a @fa<discrete_subtype_definition>, the @fa<chunk_specification> declares a @i<chunk parameter> object whose subtype (and nominal subtype) is that defined by the @fa<discrete_subtype_definition>.
!corrigendum 5.5(7)
!AI-0119-1
!AI-0250-1
!AI-0327-1
@drepl For the execution of a @fa<loop_statement>, the @fa<sequence_of_statements> is executed repeatedly, zero or more times, until the @fa<loop_statement> is complete. The @fa<loop_statement> is complete when a transfer of control occurs that transfers control out of the loop, or, in the case of an @fa<iteration_scheme>, as specified below. @dby The @i<filter> of an @i<iterator construct> (a @fa<loop_parameter_specification>, @fa<iterator_specification>, or @fa<procedural_iterator>) is defined to be @i<satisfied> when there is no @fa<iterator_filter> for the iterator construct, or when the @fa<condition> of the @fa<iterator_filter> evaluates to True for a given iteration of the iterator construct.
If a @fa<sequence_of_statements> of a @fa<loop_statement> with an iterator construct is said to be @i<conditionally executed>, then the @fa<statement>s are executed only when the filter of the iterator construct is satisfied.
The loop iterators @fa<loop_parameter_specification> and @fa<iterator_specification> can also be used in contexts other than @fa<loop_statement>s (for example, see 4.3.5 and 4.5.8). In such a context, the iterator @i<conditionally produces> values in the order specified for the associated construct below or in 5.5.2. The values produced are the values given to the loop parameter when the filter of the iterator construct is satisfied for that value. No value is produced when the @fa<condition> of an @fa<iterator_filter> evaluates to False.
For the execution of a @fa<loop_statement>, the @fa<sequence_of_statements> is executed zero or more times, until the @fa<loop_statement> is complete. The @fa<loop_statement> is complete when a transfer of control occurs that transfers control out of the loop, or, in the case of an @fa<iteration_scheme>, as specified below.
!corrigendum 5.5(8)
!AI-0266-1
!AI-0294-1
@dinsa For the execution of a @fa<loop_statement> with a @b<while> @fa<iteration_scheme>, the @fa<condition> is evaluated before each execution of the @fa<sequence_of_statements>; if the value of the @fa<condition> is True, the @fa<sequence_of_statements> is executed; if False, the execution of the @fa<loop_statement> is complete. @dinst If the reserved word @b<parallel> is present in the @fa<iteration_scheme> of a @fa<loop_statement> (a @i<parallel loop>), the iterations are partitioned into one or more @i<chunks>, each with its own separate logical thread of control (see clause 9). If a @fa<chunk_specification> is present in a parallel loop, it is elaborated first, and the result of the elaboration determines the maximum number of chunks used for the parallel loop. If the @fa<chunk_specification> is an @i<integer_>@fa<simple_expression>, the elaboration evaluates the expression, and the value of the expression determines the maximum number of chunks. If a @fa<discrete_subtype_definition> is present, the elaboration elaborates the @fa<discrete_subtype_definition>, which defines the subtype of the chunk parameter, and the number of values in this subtype determines the maximum number of chunks. After elaborating the @fa<chunk_specification>, a check is made that the determined maximum number of chunks is greater than zero. If this check fails, Program_Error is raised.
!corrigendum 5.5(9/4)
!AI-0119-1
!AI-0250-1
!AI-0251-1
!AI-0266-1
!AI-0294-1
!AI-0355-2
!AI-0416-1
@drepl For the execution of a @fa<loop_statement> with the @fa<iteration_scheme> being @b<for> @fa<loop_parameter_specification>, the @fa<loop_parameter_specification> is first elaborated. This elaboration creates the loop parameter and elaborates the @fa<discrete_subtype_definition>. If the @fa<discrete_subtype_definition> defines a subtype with a null range, the execution of the @fa<loop_statement> is complete. Otherwise, the @fa<sequence_of_statements> is executed once for each value of the discrete subtype defined by the @fa<discrete_subtype_definition> that satisfies the predicates of the subtype (or until the loop is left as a consequence of a transfer of control). Prior to each such iteration, the corresponding value of the discrete subtype is assigned to the loop parameter. These values are assigned in increasing order unless the reserved word @b<reverse> is present, in which case the values are assigned in decreasing order. @dby For the execution of a @fa<loop_statement> that has an @fa<iteration_scheme> including a @fa<loop_parameter_specification>, after elaborating the @fa<chunk_specification> and @fa<aspect_specification>, if any, the @fa<loop_parameter_specification> is elaborated. This elaborates the @fa<discrete_subtype_definition>, which defines the subtype of the loop parameter. If the @fa<discrete_subtype_definition> defines a subtype with a null range, the execution of the @fa<loop_statement> is complete. Otherwise, the @fa<sequence_of_statements> is conditionally executed once for each value of the discrete subtype defined by the @fa<discrete_subtype_definition> that satisfies the predicates of the subtype (or until the loop is left as a consequence of a transfer of control). Prior to each such iteration, the corresponding value of the discrete subtype is assigned to the loop parameter associated with the given iteration. If the loop is a parallel loop, each chunk has its own logical thread of control with its own copy of the loop parameter; otherwise (a @i<sequential loop>), a single logical thread of control performs the loop, and there is a single copy of the loop parameter. Each logical thread of control handles a distinct subrange of the values of the subtype of the loop parameter such that all values are covered with no overlaps. Within each logical thread of control, the values are assigned to the loop parameter in increasing order unless the reserved word @b<reverse> is present, in which case the values are assigned in decreasing order. In the absence of a transfer of control, the associated parallel construct of a @fa<loop_parameter_specification> is complete when all of its logical threads of control are complete.
If a @fa<chunk_specification> with a @fa<discrete_subtype_definition> is present, then the logical thread of control associated with a given chunk has its own copy of the chunk parameter initialized with a distinct value from the discrete subtype defined by the @fa<discrete_subtype_definition>. The values of the chunk parameters are assigned such that they increase with increasing values of the ranges covered by the corresponding loop parameters.
Whether or not a @fa<chunk_specification> is present in a parallel loop, the total number of iterations of the loop represents an upper bound on the number of logical threads of control devoted to the loop.
!corrigendum 5.5(9.1/4)
!AI-0250-1
!AI-0266-1
@drepl For details about the execution of a @fa<loop_statement> with the @fa<iteration_scheme> being @b<for> @fa<iterator_specification>, see 5.5.2. @dby For details about the execution of a @fa<loop_statement> with the @fa<iteration_scheme> including an @fa<iterator_specification>, see 5.5.2. For details relating to a @fa<procedural_iterator>, see 5.5.3.
!corrigendum 5.5(21)
!AI-0119-1
!AI-0312-1
!AI-0386-1
@dinsa @xcode<Summation:
@b<while> Next /= Head @b<loop> -- @ft<@i<see 3.10.1>>
Sum := Sum + Next.Value; Next := Next.Succ;
@b<end loop> Summation;>
@dinss @i<Example of a simple parallel loop:>
@xcode<-- @ft<@i<see 3.6>> @b<parallel> @b<for> I @b<in> Grid'Range(1) @b<loop>
Grid(I, 1) := (@b<for all> J @b<in> Grid'range(2) =@> Grid(I,J) = True);
@b<end loop>;>
@i<Example of a parallel loop with a chunk specification:>
@xcode<@b<declare>
@b<subtype> Chunk_Number @b<is> Natural @b<range> 1 .. 8;>
@xcode< Partial_Sum,
Partial_Max : @b<array> (Chunk_Number) @b<of> Natural := (@b<others> =@> 0); Partial_Min : @b<array> (Chunk_Number) @b<of> Natural :=
(@b<others> =@> Natural'Last);>
@xcode<@b<begin>
@b<parallel> (Chunk @b<in> Chunk_Number) @b<for> I @b<in> Grid'Range(1) @b<loop>
@b<declare>
True_Count : @b<constant> Natural := [@b<for> J @b<in> Grid'Range(2) =@> (@b<if> Grid (I, J) @b<then> 1 @b<else> 0)]'Reduce("+",0);
@b<begin>
Partial_Sum (Chunk) := @@ + True_Count; Partial_Min (Chunk) := Natural'Min(@@, True_Count); Partial_Max (Chunk) := Natural'Max(@@, True_Count);
@b<end>; @b<end loop>;>
@xcode< Put_Line
("Total=" & Partial_Sum'Reduce("+", 0)'Image &
", Min=" & Partial_Min'Reduce(Natural'Min, Natural'Last)'Image & ", Max=" & Partial_Max'Reduce(Natural'Max, 0)'Image);
@b<end>;>
@i<For an example of an> @fa<iterator_filter>@i<, see 4.5.8.>
!corrigendum 5.5.1(8/3)
!AI-0111-1
!AI-0428-1
@drepl @xhang<@xterm<Default_Iterator>This aspect is specified by a @fa<name> that denotes exactly one function declared immediately within the same declaration list in which @i<T> is declared, whose first parameter is of type @i<T> or @i<T>'Class or an access parameter whose designated type is type @i<T> or @i<T>'Class, whose other parameters, if any, have default expressions, and whose result type is an iterator type. This function is the @i<default iterator function> for @i<T>. Its result subtype is the @i<default iterator subtype> for @i<T>. The iteration cursor subtype for the default iterator subtype is the @i<default cursor subtype> for @i<T>.> @dby @xhang<@xterm<Default_Iterator>This aspect is specified by a @fa<name> that denotes exactly one function declared immediately within the same declaration list in which @i<T>, or the declaration completed by @i<T>, is declared, whose first parameter is of type @i<T> or @i<T>'Class or an access parameter whose designated type is type @i<T> or @i<T>'Class, whose other parameters, if any, have default expressions, and whose result type is an iterator type. This function is the @i<default iterator function> for @i<T>. Its result subtype is the @i<default iterator subtype> for @i<T>. The iteration cursor subtype for the default iterator subtype is the @i<default cursor subtype> for @i<T>. This aspect is inherited by descendants of type @i<T> (including @i<T>'Class).>
!corrigendum 5.5.2(2/3)
!AI-0156-1
!AI-0250-1
!AI-0266-1
@drepl @xindent<@fa<iterator_specification>@fa<@ ::=@ >@hr @ @ @ @ @fa<defining_identifier>@ @b<in>@ [@b<reverse>]@ @i<iterator_>@fa<name>@hr @ @ |@ @fa<defining_identifier>@ [:@ @fa<subtype_indication>]@ @b<of>@ [@b<reverse>]@ @i<iterable_>@fa<name>> @dby @xindent<@fa<iterator_specification>@fa<@ ::=@ >@hr @ @ @ @ @fa<defining_identifier>@ [:@ @fa<loop_parameter_subtype_indication>]@ @b<in>@ [@b<reverse>]@ @i<iterator_>@fa<name>@hr @ @ @ @ @ @ [@fa<iterator_filter>]@hr @ @ |@ @fa<defining_identifier>@ [:@ @fa<loop_parameter_subtype_indication>]@ @b<of> [@b<reverse>]@ @i<iterable_>@fa<name>@hr @ @ @ @ @ @ [@fa<iterator_filter>]>
@xindent<@fa<loop_parameter_subtype_indication>@fa<@ ::=@ >@fa<subtype_indication>@ |@ @fa<access_definition>>
@xindent<If an @fa<iterator_specification> is for a parallel construct, the reserved word @b<reverse> shall not appear in the @fa<iterator_specification>.>
!corrigendum 5.5.2(5/4)
!AI-0156-1
!AI-0183-1
@drepl The subtype defined by the @fa<subtype_indication>, if any, of an array component iterator shall statically match the component subtype of the type of the @i<iterable_>@fa<name>. The subtype defined by the @fa<subtype_indication>, if any, of a container element iterator shall statically match the default element subtype for the type of the @i<iterable_>@fa<name>. @dby The subtype defined by the @fa<loop_parameter_subtype_indication>, if any, of a generalized iterator shall statically match the iteration cursor subtype. The subtype defined by the @fa<loop_parameter_subtype_indication>, if any, of an array component iterator shall statically match the component subtype of the type of the @i<iterable_>@fa<name>. The subtype defined by the @fa<loop_parameter_subtype_indication>, if any, of a container element iterator shall statically match the default element subtype for the type of the @i<iterable_>@fa<name>.
!corrigendum 5.5.2(10/3)
!AI-0250-1
!AI-0266-1
!AI-0418-1
@drepl For a generalized iterator, the loop parameter is created, the @i<iterator_>@fa<name> is evaluated, and the denoted iterator object becomes the @i<loop iterator>. In a forward generalized iterator, the operation First of the iterator type is called on the loop iterator, to produce the initial value for the loop parameter. If the result of calling Has_Element on the initial value is False, then the execution of the @fa<loop_statement> is complete. Otherwise, the @fa<sequence_of_statements> is executed and then the Next operation of the iterator type is called with the loop iterator and the current value of the loop parameter to produce the next value to be assigned to the loop parameter. This repeats until the result of calling Has_Element on the loop parameter is False, or the loop is left as a consequence of a transfer of control. For a reverse generalized iterator, the operations Last and Previous are called rather than First and Next. @dby For a sequential generalized iterator, the loop parameter is created, the @i<iterator_>@fa<name> is evaluated, and the denoted iterator object becomes the @i<loop iterator>. In a forward generalized iterator, the operation First of the iterator type is called on the loop iterator, to produce the initial value for the loop parameter. If the result of calling Has_Element on the initial value is False, then the execution of the @fa<loop_statement> is complete. Otherwise, the @fa<sequence_of_statements> is conditionally executed and then the Next operation of the iterator type is called with the loop iterator and the current value of the loop parameter to produce the next value to be assigned to the loop parameter. This repeats until the result of calling Has_Element on the loop parameter is False, or the loop is left as a consequence of a transfer of control. For a reverse generalized iterator, the operations Last and Previous are called rather than First and Next.
For a parallel generalized iterator, the @fa<chunk_specification>, if any, of the associated parallel construct, is first elaborated, to determine the maximum number of chunks (see 5.5), and then the operation Split_Into_Chunks of the iterator type is called, with the determined maximum passed as the Max_Chunks parameter, specifying the upper bound for the number of loop parameter objects (and the number of logical threads of control) to be associated with the iterator. In the absence of a @fa<chunk_specification>, the maximum number of chunks is determined in an implementation-defined manner.
Upon return from Split_Into_Chunks, the actual number of chunks for the loop is determined by calling the Chunk_Count operation of the iterator, at which point one logical thread of control is initiated for each chunk, with an associated chunk index in the range from one to the actual number of chunks.
Within each logical thread of control, a loop parameter is created. If a @fa<chunk_specification> with a @fa<discrete_subtype_definition> is present in the associated parallel construct, then a chunk parameter is created and initialized with a value from the discrete subtype defined by the @fa<discrete_subtype_definition>, so that the order of the chosen chunk parameter values correspond to the order of the chunk indices associated with the logical threads of control. The operation First of the iterator type that has a Chunk parameter is called on the loop iterator, with Chunk initialized from the corresponding chunk index, to produce the initial value for the loop parameter. If the result of calling Has_Element on this initial value is False, then the execution of the logical thread of control is complete. Otherwise, the @fa<sequence_of_statements> is conditionally executed, and then the Next operation of the iterator type that has a Chunk parameter is called with the loop iterator, the current value of the loop parameter, and the corresponding chunk index, to produce the next value to be assigned to the loop parameter. This repeats until the result of calling Has_Element on the loop parameter is False, or the associated parallel construct is left as a consequence of a transfer of control.
In the absence of a transfer of control, the associated parallel construct of a parallel generalized iterator is complete when all of its logical threads of control are complete.
!corrigendum 5.5.2(11/3)
!AI-0250-1
!AI-0266-1
@drepl For an array component iterator, the @i<iterable_>@fa<name> is evaluated and the denoted array object becomes the @i<array for the loop>. If the array for the loop is a null array, then the execution of the @fa<loop_statement> is complete. Otherwise, the @fa<sequence_of_statements> is executed with the loop parameter denoting each component of the array for the loop, using a @i<canonical> order of components, which is last dimension varying fastest (unless the array has convention Fortran, in which case it is first dimension varying fastest). For a forward array component iterator, the iteration starts with the component whose index values are each the first in their index range, and continues in the canonical order. For a reverse array component iterator, the iteration starts with the component whose index values are each the last in their index range, and continues in the reverse of the canonical order. The loop iteration proceeds until the @fa<sequence_of_statements> has been executed for each component of the array for the loop, or until the loop is left as a consequence of a transfer of control. @dby For an array component iterator, the @fa<chunk_specification> of the associated parallel construct, if any, is first elaborated to determine the maximum number of chunks (see 5.5), and then the @i<iterable_>@fa<name> is evaluated and the denoted array object becomes the @i<array for the loop>. If the array for the loop is a null array, then the execution of the @fa<loop_statement> is complete. Otherwise, the @fa<sequence_of_statements> is conditionally executed with the loop parameter denoting each component of the array for the loop, using a @i<canonical> order of components, which is last dimension varying fastest (unless the array has convention Fortran, in which case it is first dimension varying fastest). For a forward array component iterator, the iteration starts with the component whose index values are each the first in their index range, and continues in the canonical order. For a reverse array component iterator, the iteration starts with the component whose index values are each the last in their index range, and continues in the reverse of the canonical order. For a parallel array component iterator, the iteration is broken up into contiguous chunks of the canonical order, such that all components are covered with no overlaps; each chunk has its own logical thread of control with its own loop parameter and iteration within each chunk is in the canonical order. The number of chunks is implementation defined, but is limited in the presence of a @fa<chunk_specification> to the determined maximum. The loop iteration proceeds until the @fa<sequence_of_statements> has been conditionally executed for each component of the array for the loop, or until the loop is left as a consequence of a transfer of control.
If a @fa<chunk_specification> with a @fa<discrete_subtype_definition> is present in the associated parallel construct, then the logical thread of control associated with a given chunk has a chunk parameter initialized with a distinct value from the discrete subtype defined by the @fa<discrete_subtype_definition>. The values of the chunk parameters are assigned such that they increase in the canonical order of the starting array components for the chunks.
!corrigendum 5.5.2(12/3)
!AI-0111-1
!AI-0266-1
@drepl For a container element iterator, the @i<iterable_>@fa<name> is evaluated and the denoted iterable container object becomes the @i<iterable container object for the loop>. The default iterator function for the type of the iterable container object for the loop is called on the iterable container object and the result is the @i<loop iterator>. An object of the default cursor subtype is created (the @i<loop cursor>). @dby For a container element iterator, the @fa<chunk_specification> of the associated parallel construct, if any, is first elaborated to determine the maximum number of chunks (see 5.5), and then the @i<iterable_>@fa<name> is evaluated. If the container type has Iterator_View specified, an object of the Iterator_View type is created with the discriminant referencing the iterable container object denoted by the @i<iterable_>@fa<name>. This is the @i<iterable container object for the loop>. Otherwise, the iterable container object denoted by the @i<iterable_>@fa<name> becomes the iterable container object for the loop. The default iterator function for the type of the iterable container object for the loop is called on the iterable container object and the result is the @i<loop iterator>. For a sequential container element iterator, an object of the default cursor subtype is created (the @i<loop cursor>). For a parallel container element iterator, each chunk of iterations will have its own loop cursor, again of the default cursor subtype.
!corrigendum 5.5.2(15/3)
!AI-0266-1
!AI-0429-1
@drepl @xcode<-- @ft<@i<Array component iterator example:>> @b<for> Element @b<of> Board @b<loop> -- @ft<@i<See 3.6.1.>>
Element := Element * 2.0; -- @ft<@i<Double each element of Board, a two-dimensional array.>>
@b<end loop>;> @dby @i<Example of a parallel generalized loop over an array:>
@xcode<@b<parallel> @b<for> Element @b<of> Board @b<loop> -- @ft<@i<See 3.6.1.>>
Element := Element * 2.0; -- @ft<@i<Double each element of Board, a two-dimensional array.>>
@b<end loop>;>
!corrigendum 5.5.3(0)
!AI-0189-1
!AI-0250-1
!AI-0292-1
!AI-0294-1
!AI-0308-1
!AI-0320-1
!AI-0326-2
!AI-0344-1
!AI-0355-2
!AI-0374-1
!AI-0429-1
@dinsc
A @fa<procedural_iterator> invokes a user-defined procedure, passing in the body of the enclosing @fa<loop_statement> as a parameter of an anonymous access-to-procedure type, to allow the loop body to be executed repeatedly as part of the invocation of the user-defined procedure.
@s8<@i<Syntax>>
@xindent<@fa<procedural_iterator>@fa<@ ::=@ >@hr @ @ @ @ @fa<iterator_parameter_specification>@ @b<of>@ @fa<iterator_procedure_call>@hr @ @ @ @ @ @ [@fa<iterator_filter>]>
@xindent<@fa<iterator_parameter_specification>@fa<@ ::=@ >@hr @ @ @ @ @fa<formal_part>@hr @ @ |@ (@fa<defining_identifier>{,@ @fa<defining_identifier>})>
@xindent<@fa<iterator_procedure_call>@fa<@ ::=@ >@hr @ @ @ @ @i<procedure_>@fa<name>@hr @ @ |@ @i<procedure_>@fa<prefix>@ @fa<iterator_actual_parameter_part>>
@xindent<@fa<iterator_actual_parameter_part>@fa<@ ::=@ >@hr @ @ @ @ (@fa<iterator_parameter_association>@ {,@ @fa<iterator_parameter_association>})>
@xindent<@fa<iterator_parameter_association>@fa<@ ::=@ >@hr @ @ @ @ @fa<parameter_association>@hr @ @ |@ @fa<parameter_association_with_box>>
@xindent<@fa<parameter_association_with_box>@fa<@ ::=@ >@hr @ @ @ [@ @i<formal_parameter_>@fa<selector_name>@ =@>@ ]@ <@>>
At most one @fa<iterator_parameter_association> within an @fa<iterator_actual_parameter_part> shall be a @fa<parameter_association_with_box>.
@s8<@i<Name Resolution Rules>>
The @fa<name> or @fa<prefix> given in an @fa<iterator_procedure_call> shall resolve to denote a callable entity @i<C> (the @i<iterating procedure>) that is a procedure, or an entry renamed as (viewed as) a procedure. When there is an @fa<iterator_actual_parameter_part>, the @fa<prefix> can be an @fa<implicit_dereference> of an access-to-subprogram value.
An @fa<iterator_procedure_call> without a @fa<parameter_association_with_box> is equivalent to one with an @fa<iterator_actual_parameter_part> with an additional @fa<parameter_association_with_box> at the end, with the @i<formal_parameter_>@fa<selector_name> identifying the last formal parameter of the callable entity denoted by the @fa<name> or @fa<prefix>.
An @fa<iterator_procedure_call> shall contain at most one @fa<iterator_parameter_association> for each formal parameter of the callable entity @i<C>. Each formal parameter without an @fa<iterator_parameter_association> shall have a @fa<default_expression> (in the profile of the view of @i<C> denoted by the @fa<name> or @fa<prefix>).
The formal parameter of the callable entity @i<C> associated with the @fa<parameter_association_with_box> shall be of an anonymous access-to-procedure type @i<A>.
@s8<@i<Legality Rules>>
The anonymous access-to-procedure type @i<A> shall have at least one formal parameter in its parameter profile. If the @fa<iterator_parameter_specification> is a @fa<formal_part>, then this @fa<formal_part> shall be mode conformant with that of @i<A>. If the @fa<iterator_parameter_specification> is a list of @fa<defining_identifier>s, the number of formal parameters of @i<A> shall be the same as the length of this list.
If the @fa<name> or @fa<prefix> given in an @fa<iterator_procedure_call> denotes an abstract subprogram, the subprogram shall be a dispatching subprogram.
@s8<@i<Static Semantics>>
A @fa<loop_statement> with an @fa<iteration_scheme> that has a @fa<procedural_iterator> is equivalent to a local declaration of a procedure P followed by a @fa<procedure_call_statement> that is formed from the @fa<iterator_procedure_call> by replacing the <@> of the @fa<parameter_association_with_box> with P'Access. The @fa<formal_part> of the locally declared procedure P is formed from the @fa<formal_part> of the anonymous access-to-procedure type @i<A>, by replacing the @fa<identifier> of each formal parameter of this @fa<formal_part> with the @fa<identifier> of the corresponding formal parameter or element of the list of @fa<defining_identifier>s given in the @fa<iterator_parameter_specification>. The body of @i<P> consists of the conditionally executed @fa<sequence_of_statements>. The procedure P is called the @i<loop body procedure>.
In a procedural iterator, the Parallel_Calls aspect (see 9.10.1) of the loop body procedure is True if the reserved word @b<parallel> occurs in the corresponding loop statement, and False otherwise.
The following aspects may be specified for a callable entity @i<S> that has exactly one formal parameter of an anonymous access-to-subprogram type:
@xhang<@xterm<Allows_Exit> The Allows_Exit aspect is of type Boolean. The specified value shall be static. The Allows_Exit aspect of an inherited primitive subprogram is True if Allows_Exit is True either for the corresponding subprogram of the progenitor type or for any other inherited subprogram that it overrides. If not specified or inherited as True, the Allows_Exit aspect of a callable entity is False. For an entry, only a confirming specification of False is permitted for the Allows_Exit aspect.>
@xindent<Specifying the Allows_Exit aspect to be True for a subprogram indicates that the subprogram @i<allows exit>, meaning that it is prepared to be completed by arbitrary transfers of control from the loop body procedure, including propagation of exceptions. A subprogram for which Allows_Exit is True should use finalization as appropriate rather than exception handling to recover resources and make any necessary final updates to data structures.>
@xhang<@xterm<Parallel_Iterator> The Parallel_Iterator aspect is of type Boolean. The specified value shall be static. The Parallel_Iterator aspect of an inherited primitive subprogram is True if Parallel_Iterator is True either for the corresponding subprogram of the progenitor type or for any other inherited subprogram that it overrides. If not specified or inherited as True, the Parallel_Iterator aspect of a callable entity is False.>
@xindent<Specifying the Parallel_Iterator aspect to be True for a callable entity indicates that the entity might invoke the loop body procedure from multiple distinct logical threads of control. The Parallel_Iterator aspect for a subprogram shall be statically False if the subprogram allows exit.>
@s8<@i<Legality Rules>>
If a callable entity overrides an inherited dispatching subprogram that allows exit, the overriding callable entity also shall allow exit. If a callable entity overrides an inherited dispatching subprogram that has a True Parallel_Iterator aspect, the overriding callable entity also shall have a True Parallel_Iterator aspect.
A @fa<loop_statement> with a @fa<procedural_iterator> as its @fa<iteration_scheme> shall begin with the reserved word @b<parallel> if and only if the callable entity identified in the @fa<iterator_procedure_call> has a Parallel_iterator aspect of True.
If the actual parameter of an anonymous access-to-subprogram type, passed in an explicit call of a subprogram for which the Parallel_Iterator aspect is True, is of the form @i<P>'Access, the designated subprogram @i<P> shall have a Parallel_Calls aspect True (see 9.10.1).
The @fa<sequence_of_statements> of a @fa<loop_statement> with a @fa<procedural_iterator> as its @fa<iteration_scheme> shall contain an @fa<exit_statement>, return statement, @fa<goto_statement>, or @fa<requeue_statement> that leaves the loop only if the callable entity associated with the @fa<procedural_iterator> allows exit.
The @fa<sequence_of_statements> of a @fa<loop_statement> with a @fa<procedural_iterator> as its @fa<iteration_scheme> shall not contain an @fa<accept_statement> whose @fa<entry_declaration> occurs outside the @fa<loop_statement>.
@s8<@i<Dynamic Semantics>>
For the execution of a @fa<loop_statement> with an @fa<iteration_scheme> that has a @fa<procedural_iterator>, the procedure denoted by the @fa<name> or @fa<prefix> of the @fa<iterator_procedure_call> (the @i<iterating procedure>) is invoked, passing an access value designating the loop body procedure as a parameter. The iterating procedure then calls the loop body procedure zero or more times and returns, whereupon the @fa<loop_statement> is complete. If the @b<parallel> reserved word is present, the iterating procedure might invoke the loop body procedure from multiple distinct logical threads of control. The @fa<aspect_specification>, if any, is elaborated prior to the invocation of the iterating procedure.
@s8<@i<Bounded (Run-Time) Errors>>
If the callable entity identified in the @fa<iterator_procedure_call> allows exit, then it is a bounded error for a call of the loop body procedure to be performed from within an abort-deferred operation (see 9.8), unless the entire @fa<loop_statement> was within the same abort-deferred operation. If detected, Program_Error is raised at the point of the call; otherwise, a transfer of control from the @fa<sequence_of_statements> of the @fa<loop_statement> might not terminate the @fa<loop_statement>, and the loop body procedure might be called again.
If a @fa<loop_statement> with the @fa<procedural_iterator> as its @fa<iteration_scheme> (see 5.5) does not begin with the reserved word @b<parallel>, it is a bounded error if the loop body procedure is invoked from a different logical thread of control than the one that initiates the @fa<loop_statement>. If detected, Program_Error is raised; otherwise, conflicts associated with concurrent executions of the loop body procedure can occur without being detected by the applicable conflict check policy (see 9.10.1). Furthermore, propagating an exception or making an attempt to exit in the presence of multiple threads of control might not terminate the @fa<loop_statement>, deadlock might occur, or the loop body procedure might be called again.
@s8<@i<Examples>>
@i<Example of iterating over a map from My_Key_Type to My_Element_Type (see A.18.4):>
@xcode<@b<for> (C : Cursor) @b<of> My_Map.Iterate @b<loop>
Put_Line (My_Key_Type'Image (Key (C)) & " =@> " &
My_Element_Type'Image (Element (C)));
@b<end loop>;>
@xcode<--@ft<@i< The above is equivalent to:>>>
@xcode<@b<declare>
@b<procedure> P (C : Cursor) @b<is> @b<begin>
Put_Line (My_Key_Type'Image (Key (c)) & " =@> " &
My_Element_Type'Image (Element (C)));
@b<end> P;
@b<begin>
My_Map.Iterate (P'access);
@b<end>;>
@i<Example of iterating over the environment variables (see A.17):>
@xcode<@b<for> (Name, Val) @b<of> Ada.Environment_Variables.Iterate(<@>) @b<loop>
--@ft<@i< "(<@>)" is optional because it is the last parameter>> Put_Line (Name & " =@> " & Val);
@b<end loop>;>
@xcode<--@ft<@i< The above is equivalent to:>>>
@xcode<@b<declare>
@b<procedure> P (Name : String; Val : String) @b<is> @b<begin>
Put_Line (Name & " =@> " & Val);
@b<end> P;
@b<begin>
Ada.Environment_Variables.Iterate (P'access);
@b<end>;>
!corrigendum 5.6.1(0)
!AI-0119-1
!AI-0404-1
!AI-0427-1
!AI-0429-1
!AI-0436-1
@dinsc
A @fa<parallel_block_statement> comprises two or more @fa<sequence_of_statements> separated by @b<and> where each represents an independent activity that is intended to proceed concurrently with the others.
@s8<@i<Syntax>>
@xindent<@fa<parallel_block_statement>@fa<@ ::=@ >@hr @ @ @ @ @b<parallel>@ [(@fa<chunk_specification>)]@ [@fa<aspect_specification>]@ @b<do>@hr @ @ @ @ @ @ @ @fa<sequence_of_statements>@hr @ @ @ @ @b<and>@hr @ @ @ @ @ @ @ @fa<sequence_of_statements>@hr @ @ @ {@b<and>@hr @ @ @ @ @ @ @ @fa<sequence_of_statements>}@hr @ @ @ @ @b<end@ do>;>
The @fa<chunk_specification>, if any, of a @fa<parallel_block_statement> shall be an @i<integer_>@fa<simple_expression>.
@s8<@i<Dynamic Semantics>>
For the execution of a @fa<parallel_block_statement>, the @fa<chunk_specification> and the @fa<aspect_specification>, if any, are elaborated in an arbitrary order. After elaborating the @fa<chunk_specification>, if any, a check is made that the determined maximum number of chunks is greater than zero. If this check fails, Program_Error is raised.
Then, the various @fa<sequence_of_statements> are grouped into one or more @i<chunks>, each with its own logical thread of control (see clause 9), up to the maximum number of chunks specified by the @fa<chunk_specification>, if any. Within each chunk every @fa<sequence_of_statements> of the chunk is executed in turn, in an arbitrary order. The @fa<parallel_block_statement> is complete once every one of the @fa<sequence_of_statements> has completed, either by reaching the end of its execution, or due to a transfer of control out of the construct by one of the @fa<sequence_of_statements> (see 5.1).
@s8<@i<Examples>>
@i<Example of a parallel block used to walk a binary tree in parallel:>
@xcode<@b<procedure> Traverse (T : Expr_Ptr) @b<is> --@FT<@I< see 3.9.1>> @b<begin>
@b<if> T /= @b<null> @b<and> @b<then>
T.@b<all> @b<in> Binary_Operation'Class --@FT<@I< see 3.9.1>>
@b<then> --@FT<@I< recurse down the binary tree>>
@b<parallel do>
Traverse (T.Left);
@b<and>
Traverse (T.Right);
@b<and>
Ada.Text_IO.Put_Line
("Processing " & Ada.Tags.Expanded_Name (T'Tag));
@b<end do>;
@b<end if>;
@b<end> Traverse;>
@i<Example of a parallel block used to search two halves of a string in parallel:>
@xcode<@b<function> Search (S : String; Char : Character) @b<return> Boolean @b<is> @b<begin>
@b<if> S'Length <= 1000 @b<then>
--@FT<@I< Sequential scan>> @b<return> (@b<for some> C @b<of> S =@> C = Char);
@b<else>
--@FT<@I< Parallel divide and conquer>> @b<declare>
Mid : @b<constant> Positive := S'First + S'Length/2 - 1;
@b<begin>
@b<parallel do> @b<for> C @b<of> S(S'First .. Mid) @b<loop> @b<if> C = Char @b<then> @b<return> True; --@FT<@I< Terminates enclosing@b< do>>> @b<end if>; @b<end loop>; @b<and> @b<for> C @b<of> S(Mid + 1 .. S'Last) @b<loop> @b<if> C = Char @b<then> @b<return> True; --@FT<@I< Terminates enclosing@b< do>>> @b<end if>; @b<end loop>; @b<end do>; --@FT<@I< Not found>> @b<return> False;
@b<end>;
@b<end if>;
@b<end> Search;>
!corrigendum 6.1.1(1/4)
!AI-0220-1
!AI-0272-1
!AI-0396-1
@drepl For a noninstance subprogram, a generic subprogram, or an entry, the following language-defined aspects may be specified with an @fa<aspect_specification> (see 13.1.1): @dby For a noninstance subprogram (including a generic formal subprogram), a generic subprogram, an entry, or an access-to-subprogram type, the following language-defined assertion aspects may be specified with an @fa<aspect_specification> (see 13.1.1):
!corrigendum 6.1.1(7/4)
!AI-0170-1
!AI-0418-1
@drepl Within the expression for a Pre'Class or Post'Class aspect for a primitive subprogram @i<S> of a tagged type @i<T>, a @fa<name> that denotes a formal parameter (or @i<S>'Result) of type @i<T> is interpreted as though it had a (notional) type @i<NT> that is a formal derived type whose ancestor type is @i<T>, with directly visible primitive operations. Similarly, a @fa<name> that denotes a formal access parameter (or @i<S>'Result) of type access-to-@i<T> is interpreted as having type access-to-@i<NT>. The result of this interpretation is that the only operations that can be applied to such @fa<name>s are those defined for such a formal derived type. @dby Within the expression for a Pre'Class or Post'Class aspect for a primitive subprogram @i<S> of a tagged type @i<T>, a @fa<name> that denotes a formal parameter (or @i<S>'Result) of type @i<T> is interpreted as though it had a (notional) nonabstract type @i<NT> that is a formal derived type whose ancestor type is @i<T>, with directly visible primitive operations. Similarly, a @fa<name> that denotes a formal access parameter (or @i<S>'Result for an access result) of type access-to-@i<T> is interpreted as having type access-to-@i<NT>. The result of this interpretation is that the only operations that can be applied to such @fa<name>s are those defined for such a formal derived type.
!corrigendum 6.1.1(22.1/4)
!AI-0198-1
!AI-0280-2
!AI-0422-1
@drepl @xbullet<a @fa<predicate> of a @fa<quantified_expression>;> @dby @xbullet<a name statically denoting a full constant declaration which is known to have no variable views (see 3.3);>
@xbullet<a name statically denoting a nonaliased @b<in> parameter of an elementary type;>
@xbullet<an Old @fa<attribute_reference>;>
@xbullet<an invocation of a predefined operator where all of the operands are known on entry;>
@xbullet<a function call where the function has aspect Global =@> @b<null> where all of the actual parameters are known on entry;>
@xbullet<a @fa<selected_component> of a known-on-entry @fa<prefix>;>
@xbullet<an @fa<indexed_component> of a known-on-entry @fa<prefix> where all index @fa<expression>s are known on entry;>
@xbullet<a parenthesized known-on-entry @fa<expression>;>
@xbullet<a @fa<qualified_expression> or @fa<type_conversion> whose operand is a known-on-entry expression;>
@xbullet<a @fa<conditional_expression> where all of the @fa<condition>s, @i<selecting_>@fa<expression>s, and @i<dependent_>@fa<expression>s are known on entry.>
A subexpression of a postcondition expression is @i<unconditionally evaluated>, @i<conditionally evaluated>, or @i<repeatedly evaluated>. A subexpression is considered unconditionally evaluated unless it is conditionally evaluated or repeatedly evaluated.
The following subexpressions are repeatedly evaluated:
@xbullet<A subexpression of a predicate of a @fa<quantified_expression>;>
@xbullet<A subexpression of the expression of an @fa<array_component_association>;>
@xbullet<A subexpression of the expression of a @fa<container_element_association>.>
For a subexpression that is conditionally evaluated, there is a set of @i<determining expressions> that determine whether the subexpression is actually evaluated at run time. Subexpressions that are conditionally evaluated and their determining expressions are as follows:
@xbullet<For an @fa<if_expression> that is not repeatedly evaluated, a subexpression of any part other than the first condition is conditionally evaluated, and its determining expressions include all @fa<condition>s of the @fa<if_expression> that precede the subexpression textually;>
@xbullet<For a @fa<case_expression> that is not repeatedly evaluated, a subexpression of any @i<dependent_>@fa<expression> is conditionally evaluated, and its determining expressions include the @i<selecting_>@fa<expression> of the @fa<case_expression>;>
!corrigendum 6.1.1(24/3)
!AI-0217-1
!AI-0280-2
!AI-0368-2
@drepl @xbullet<a @fa<membership_choice> other than the first of a membership operation.> @dby @xbullet<For a membership test that is not repeatedly evaluated, a
subexpression of a @fa<membership_choice> other than the first is conditionally evaluated, and its determining expressions include the @i<tested_>@fa<simple_expression> and the preceding @fa<membership_choice>s of the membership test.>
A conditionally evaluated subexpression is @i<determined to be unevaluated> at run time if its set of determining expressions are all known on entry, and when evaluated on entry their values are such that the given subexpression is not evaluated.
!corrigendum 6.1.1(26.10/4)
!AI-0185-1
!AI-0388-1
@drepl @xindent<The nominal subtype of X'Old is as implied by the above definitions. The expected type of the prefix of an Old attribute is that of the attribute. Similarly, if an Old attribute shall resolve to be of some type, then the prefix of the attribute shall resolve to be of that type.> @dby @xindent<The type and nominal subtype of X'Old are as implied by the above definitions.>
!corrigendum 6.1.1(27/3)
!AI-0217-1
!AI-0280-2
@drepl @xindent<Reference to this attribute is only allowed within a postcondition
expression. The @fa<prefix> of an Old @fa<attribute_reference> shall not contain a Result @fa<attribute_reference>, nor an Old @fa<attribute_reference>, nor a use of an entity declared within the postcondition expression but not within @fa<prefix> itself (for example, the loop parameter of an enclosing @fa<quantified_expression>). The @fa<prefix> of an Old @fa<attribute_reference> that is potentially unevaluated shall statically denote an entity.>
@dby @xindent<Reference to this attribute is only allowed within a postcondition
expression. The @fa<prefix> of an Old @fa<attribute_reference> shall not contain a Result @fa<attribute_reference>, nor an Old @fa<attribute_reference>, nor a use of an entity declared within the postcondition expression but not within @fa<prefix> itself (for example, the loop parameter of an enclosing @fa<quantified_expression>). The @fa<prefix> of an Old @fa<attribute_reference> shall statically name (see 4.9) an entity, unless the @fa<attribute_reference> is unconditionally evaluated, or is conditionally evaluated where all of the determining expressions are known on entry.>
!corrigendum 6.1.1(29/4)
!AI-0185-1
!AI-0220-1
!AI-0388-1
@drepl @xhang<@xterm<F'Result>Within
a postcondition expression for function F, denotes the result object of the function. The type of this attribute is that of the function result except within a Post'Class postcondition expression for a function with a controlling result or with a controlling access result. For a controlling result, the type of the attribute is @i<T>'Class, where @i<T> is the function result type. For a controlling access result, the type of the attribute is an anonymous access type whose designated type is @i<T>'Class, where @i<T> is the designated type of the function result type.>
@dby @xhang<@xterm<F'Result>Within
a postcondition expression for F, denotes the return object of the function call for which the postcondition expression is evaluated. The type of this attribute is that of the result subtype of the function or access-to-function type except within a Post'Class postcondition expression for a function with a controlling result or with a controlling access result; in those cases the type of the attribute is described above as part of the Name Resolution Rules for Post'Class.>
!corrigendum 6.1.1(39/3)
!AI-0220-1
!AI-0272-1
!AI-0280-2
!AI-0373-1
@drepl For a call via an access-to-subprogram value, all precondition and postcondition checks performed are determined by the subprogram or entry denoted by the prefix of the Access attribute reference that produced the value. @dby For a call via an access-to-subprogram value, precondition and postcondition checks performed are as determined by the subprogram or entry denoted by the prefix of the Access attribute reference that produced the value. In addition, a precondition check of any precondition expression associated with the access-to-subprogram type is performed. Similarly, a postcondition check of any postcondition expression associated with the access-to-subprogram type is performed.
For a call on a generic formal subprogram, precondition and postcondition checks performed are as determined by the subprogram or entry denoted by the actual subprogram, along with any specific precondition and specific postcondition of the formal subprogram itself.
@s8<@i<Implementation Permissions>>
An implementation may evaluate a known-on-entry subexpression of a postcondition expression of an entity at the place where X'Old constants are created for the entity, with the normal evaluation of the postcondition expression, or both.
!corrigendum 6.1.2(0)
!AI-0079-3
!AI-0375-1
!AI-0380-1
!AI-0416-1
!AI-0422-1
!AI-0425-1
!AI-0427-1
@dinsc
The Global and Global'Class aspects of a program unit are used to identify the objects global to the unit that might be read or written during its execution.
@s8<@i<Syntax>>
@xindent<@fa<global_aspect_definition>@fa<@ ::=@ >@hr @ @ @ @ @b<null>@hr @ @ |@ Unspecified@hr @ @ |@ @fa<global_mode> @fa<global_designator>@hr @ @ |@ (@fa<global_aspect_element>{; @fa<global_aspect_element>})>
@xindent<@fa<global_aspect_element>@fa<@ ::=@ >@hr @ @ @ @ @fa<global_mode> @fa<global_set>@hr @ @ |@ @fa<global_mode> @b<all>@hr @ @ |@ @fa<global_mode> @b<synchronized>>
@xindent<@fa<global_mode>@fa<@ ::=@ >@hr @ @ @ @ @fa<basic_global_mode>@hr @ @ |@ @fa<extended_global_mode>>
@xindent<@fa<basic_global_mode>@fa<@ ::=@ >@b<in> | @b<in out> | @b<out>>
@xindent<@fa<global_set>@fa<@ ::=@ >@fa<global_name> {, @fa<global_name>}>
@xindent<@fa<global_designator>@fa<@ ::=@ >@b<all> | @b<synchronized> | @fa<global_name>>
@xindent<@fa<global_name>@fa<@ ::=@ >@i<object_>@fa<name> | @i<package_>@fa<name>>
@s8<@i<Name Resolution Rules>>
A @fa<global_name> shall resolve to statically name an object or a package (including a limited view of a package).
@s8<@i<Static Semantics>>
For a subprogram, an entry, an access-to-subprogram type, a task unit, a protected unit, or a library package or generic library package, the following language-defined aspect may be specified with an @fa<aspect_specification> (see 13.1.1):
@xhang<@xterm<Global>The Global aspect shall be specified with a @fa<global_aspect_definition>.>
@xindent<The Global aspect identifies the set of variables (which, for the purposes of this clause, includes all constants except those which are known to have no variable views (see 3.3)) that are global to a callable entity or task body, and that are read or updated as part of the execution of the callable entity or task body. If specified for a protected unit, it refers to all of the protected operations of the protected unit. Constants of any type may also be mentioned in a Global aspect.>
@xindent<If not specified or otherwise defined below, the aspect defaults to the Global aspect for the enclosing library unit if the entity is declared at library level, and to Unspecified otherwise. If not specified for a library unit, the aspect defaults to @fc<Global =@> @b<null>> for a library unit that is declared Pure, and to @fc<Global =@> Unspecified> otherwise.>
For a dispatching subprogram, the following language-defined aspect may be specified with an @fa<aspect_specification> (see 13.1.1):
@xhang<@xterm<Global'Class>The Global'Class aspect shall be specified with a @fa<global_aspect_definition>. This aspect identifies an upper bound on the set of variables global to a dispatching operation that can be read or updated as a result of a dispatching call on the operation. If not specified, the aspect defaults to the Global aspect for the dispatching subprogram.>
Together, we refer to the Global and Global'Class aspects as @i<global> aspects.
A @fa<global_aspect_definition> defines the Global or Global'Class aspect of some entity. The Global aspect identifies the sets of global variables that can be read, written, or modified as a side effect of executing the operation(s) associated with the entity. The Global'Class aspect associated with a dispatching operation of type @i<T> represents a restriction on the Global aspect on a corresponding operation of any descendant of type @i<T>.
The Global aspect for a callable entity defines the global variables that might be referenced as part of a call on the entity, including any assertion expressions that apply to the call (even if not enabled), including preconditions, postconditions, predicates, and type invariants.
The Global aspect for an access-to-subprogram object (or subtype) identifies the global variables that might be referenced when calling via the object (or any object of that subtype) including assertion expressions that apply.
For a predefined operator of an elementary type, the function representing an enumeration literal, or any other static function (see 4.9), the Global aspect is @b<null>. For a predefined operator of a composite type, the Global aspect of the operator defaults to that of the enclosing library unit (unless a Global aspect is specified for the type @emdash see H.7).
The following is defined in terms of operations that are performed by or on behalf of an entity. The rules on operations apply to the entity(s) associated with those operations.
The global variables associated with any @fa<global_mode> can be read as a side effect of an operation. The @b<in out> and @b<out> @fa<global_mode>s together identify the set of global variables that can be updated as a side effect of an operation. Creating an access-to-variable value that designates an object is considered an update of the designated object, and creating an access-to-constant value that designates an object is considered a read of the designated object.
The overall set of objects associated with each @fa<global_mode> includes all objects identified for the mode in the @fa<global_aspect_definition>.
A @fa<global_set> identifies a @i<global variable set> as follows:
@xbullet<@b<all> identifies the set of all global variables;> @xbullet<@b<synchronized> identifies the set of all synchronized variables (see 9.10), as well as variables of a composite type all of whose non-discriminant subcomponents are synchronized;> @xbullet<@fa<global_name>{, @fa<global_name>} identifies the union of the sets of variables identified by the @fa<global_name>s in the list, for the following forms of @fa<global_name>:>
@xinbull<@i<object_>@fa<name> identifies the specified global variable (or constant);>
@xinbull<@i<package_>@fa<name> identifies the set of all variables declared in the private part or body of the package, or anywhere within a private descendant of the package.>
@s8<@i<Legality Rules>>
Within a @fa<global_aspect_definition>, a given @fa<global_mode> shall be specified at most once. Similarly, within a @fa<global_aspect_definition>, a given entity shall be named at most once by a @fa<global_name>.
If an entity (other than a library package or generic library package) has a Global aspect other than Unspecified or @b<in out all>, then the associated operation(s) shall read only those variables global to the entity that are within the global variable set associated with the @b<in>, @b<in out>, or @b<out> @fa<global_mode>s, and the operation(s) shall update only those variables global to the entity that are within the global variable set associated with either the @b<in out> or @b<out> @fa<global_mode>s. In the absence of the No_Hidden_Indirect_Globals restriction (see H.4), this ignores objects reached via a dereference of an access value. The above rule includes any possible Global effects of calls occurring during the execution of the operation, except for the following excluded calls:
@xbullet<calls to formal subprograms;> @xbullet<calls associated with operations on formal subtypes;> @xbullet<calls through formal objects of an access-to-subprogram type;> @xbullet<calls through access-to-subprogram parameters;> @xbullet<calls on operations with Global aspect Unspecified.>
The possible Global effects of these excluded calls (other than those that are Unspecified) are taken into account by the caller of the original operation, by presuming they occur at least once during its execution. For calls that are not excluded, the possible Global effects of the call are those permitted by the Global aspect of the associated entity, or by its Global'Class aspect if a dispatching call.
If a Global aspect other than Unspecified or @b<in out all> applies to an access-to-subprogram type, then the @fa<prefix> of an Access @fa<attribute_reference> producing a value of such a type shall denote a subprogram whose Global aspect is not Unspecified and is @i<covered> by that of the result type, where a global aspect @i<G1> is @i<covered> by a global aspect @i<G2> if the set of variables that @i<G1> identifies as readable or updatable is a subset of the corresponding set for @i<G2>. Similarly on a conversion to such a type, the operand shall be of a named access-to-subprogram type whose Global aspect is covered by that of the target type.
For a subprogram that is a dispatching operation of a tagged type @i<T>, each mode of its Global aspect shall identify a subset of the variables identified by the corresponding mode, or by the @b<in out> mode, of the Global'Class aspect of a corresponding dispatching subprogram of any ancestor of @i<T>, unless the aspect of that ancestor is Unspecified.
@s8<@i<Implementation Permissions>>
An implementation need not require that all references to a constant object be accounted for by the Global or Global'Class aspect when it is considered a variable in the above rules if the implementation can determine that the object is in fact immutable.
Implementations may perform additional checks on calls to operations with an Unspecified Global aspect to ensure that they do not violate any limitations associated with the point of call.
Implementations may extend the syntax or semantics of the Global aspect in an implementation-defined manner; for example, supporting additional @fa<global_mode>s.
@s9<NOTES@hr For an example of the use of these aspects and attributes, see the Vector container definition in A.18.2.>
!corrigendum 6.2(10/4)
!AI-0236-1
!AI-0317-1
@drepl A parameter of a by-reference type is passed by reference, as is an explicitly aliased parameter of any type. Each value of a by-reference type has an associated object. For a parenthesized expression, @fa<qualified_expression>, or view conversion, this object is the one associated with the operand. For a value conversion, the associated object is the anonymous result object if such an object is created (see 4.6); otherwise it is the associated object of the operand. For a @fa<conditional_expression>, this object is the one associated with the evaluated @i<dependent_>@fa<expression>. @dby A parameter of a by-reference type is passed by reference, as is an explicitly aliased parameter of any type. Each value of a by-reference type has an associated object. For a value conversion, the associated object is the anonymous result object if such an object is created (see 4.6); otherwise it is the associated object of the operand. In other cases, the object associated with the evaluated operative constituent of the @fa<name> or @fa<expression> (see 4.4) determines its associated object.
!corrigendum 6.4.1(6.17/3)
!AI-0216-1
!AI-0324-1
@drepl @xbullet<For each @fa<name> @i<N> that is passed as a parameter of mode @b<in out> or @b<out> to the call @i<C>, there is no other @fa<name> among the other parameters of mode @b<in out> or @b<out> to @i<C> that is known to denote the same object.> @dby @xbullet<For each @fa<name> @i<N> denoting an object of an elementary type that is passed as a parameter of mode @b<in out> or @b<out> to the call @i<C>, there is no other @fa<name> among the other parameters of mode @b<in out> or @b<out> to @i<C> that is known to denote the same object.>
!corrigendum 6.5(5/3)
!AI-0173-1
!AI-0418-1
@drepl A function body shall contain at least one return statement that applies to the function body, unless the function contains @fa<code_statement>s. A @fa<simple_return_statement> shall include an @fa<expression> if and only if it applies to a function body. An @fa<extended_return_statement> shall apply to a function body. An @fa<extended_return_statement> with the reserved word @b<constant> shall include an @fa<expression>. @dby A function body shall contain at least one return statement that applies to the function body, unless the function contains @fa<code_statement>s. A @fa<simple_return_statement> shall include an @fa<expression> if and only if it applies to a function body. An @fa<extended_return_statement> shall apply to a function body. An @fa<extended_return_object_declaration> with the reserved word @b<constant> shall include an @fa<expression>.
The @fa<@i<expression>> @i<of an> @fa<@i<extended_return_statement>> is the @fa<expression> (if any) of the @fa<extended_return_object_declaration> of the @fa<extended_return_statement>.
!corrigendum 6.5.1(1/3)
!AI-0269-1
!AI-0418-1
@drepl Specifying aspect No_Return to have the value True indicates that a procedure cannot return normally; it may propagate an exception or loop forever. @dby Specifying aspect No_Return to have the value True indicates that a subprogram cannot return normally; it may, for example, propagate an exception or loop forever.
!corrigendum 6.8(3/4)
!AI-0075-1
!AI-0408-1
@dinsa The expected type for the @fa<expression> or @fa<aggregate> of an @fa<expression_function_declaration> is the result type (see 6.5) of the function. @dinss
@s8<@i<Static Semantics>>
An @fa<expression_function_declaration> that is not a completion declares an @i<expression function>. The @i<return expression of an expression function> is the @fa<expression> or @fa<aggregate> of the @fa<expression_function_declaration>. A completion is not allowed for an @fa<expression_function_declaration>; however, an @fa<expression_function_declaration> can complete a previous declaration.
A @i<potentially static expression> is defined in the same way as a static expression except that
@xbullet<a name denoting a formal parameter of an expression function is a potentially static expression; and>
@xbullet<each use of "static expression" in the definition of "static expression" is replaced with a corresponding use of "potentially static expression" in the definition of "potentially static expression".>
The following language-defined representation aspect may be specified for an expression function:
@xhang<@xterm<Static>The type of aspect Static is Boolean. When aspect Static is True for an expression function, the function is a @i<static expression function>. If directly specified, the @fa<aspect_definition> shall be a static expression.>
@xindent<The Static value for an inherited function is True if some corresponding primitive function of the parent or progenitor type is a static expression function; otherwise, if not directly specified, the aspect is False.>
A static expression function is a static function; see 4.9.
!corrigendum 6.8(5/4)
!AI-0075-1
!AI-0191-1
@dinsa If the result subtype has one or more unconstrained access discriminants, the accessibility level of the anonymous access type of each access discriminant, as determined by the @fa<expression> or @fa<aggregate> of the @fa<expression_function_declaration>, shall not be statically deeper than that of the master that elaborated the @fa<expression_function_declaration>. @dinss Aspect Static shall be specified to have the value True only if the associated @fa<expression_function_declaration>: @xbullet<is not a completion;> @xbullet<has an @fa<expression> that is a potentially static expression;> @xbullet<contains no calls to itself;> @xbullet<each parameter (if any) is of mode @b<in> and is of a static subtype;> @xbullet<has a result subtype that is a static subtype;> @xbullet<has no applicable precondition or postcondition expression; and> @xbullet<for result type @i<R>, if the function is a boundary entity for type @i<R> (see 7.3.2), no type invariant applies to type @i<R>; if @i<R> has a component type @i<C>, a similar rule applies to @i<C>.>
!corrigendum 7.3.2(8/3)
!AI-0075-1
!AI-0191-1
!AI-0199-1
@drepl If the Type_Invariant'Class aspect is specified for a tagged type @i<T>, then the invariant expression applies to all descendants of @i<T>. @dby If the Type_Invariant'Class aspect is specified for a tagged type @i<T>, then a @i<corresponding expression> also applies to each nonabstract descendant @i<T1> of @i<T> (including @i<T> itself if it is nonabstract). The corresponding expression is constructed from the associated expression as follows:
@xbullet<References to nondiscriminant components of @i<T> (or to @i<T> itself) are replaced with references to the corresponding components of @i<T1> (or to @i<T1> as a whole).>
@xbullet<References to discriminants of @i<T> are replaced with references to the corresponding discriminant of @i<T1>, or to the specified value for the discriminant, if the discriminant is specified by the @fa<derived_type_definition> for some type that is an ancestor of @i<T1> and a descendant of @i<T> (see 3.7).>
For a nonabstract type @i<T>, a callable entity is said to be a @i<boundary entity> for @i<T> if it is declared within the immediate scope of @i<T> (or by an instance of a generic unit, and the generic is declared within the immediate scope of type @i<T>), or is the Read or Input stream-oriented attribute of type @i<T>, and either:
@xbullet<@i<T> is a private type or a private extension and the callable entity is visible outside the immediate scope of type T or overrides an inherited operation that is visible outside the immediate scope of @i<T>; or>
@xbullet<@i<T> is a record extension, and the callable entity is a primitive operation visible outside the immediate scope of type @i<T> or overrides an inherited operation that is visible outside the immediate scope of @i<T>.>
!corrigendum 7.3.2(15/4)
!AI-0075-1
!AI-0191-1
!AI-0193-1
@drepl @xbullet<After a successful call on the Read or Input stream attribute of the type @i<T>, the check is performed on the object initialized by the stream attribute;> @dby @xbullet<Upon successful return from a call on any callable entity which is a boundary entity for @i<T>, an invariant check is performed on each object which is subject to an invariant check for @i<T>. In the case of a call to a protected operation, the check is performed before the end of the protected action. In the case of a call to a task entry, the check is performed before the end of the rendezvous. The following objects of a callable entity are subject to an invariant check for @i<T>:>
@xinbull<a result with a nominal type that has a part of type @i<T>;>
!corrigendum 7.3.2(17/4)
!AI-0075-1
!AI-0191-1
@drepl @xinbull<is declared within the immediate scope of type @i<T> (or by an instance of a generic unit, and the generic is declared within the immediate scope of type @i<T>),> @dby @xinbull<an @i<out> or @i<in out> parameter whose nominal type has a part of type @i<T>;>
@xinbull<an access-to-object parameter or result whose designated nominal type has a part of type @i<T>; or>
!corrigendum 7.3.2(19/3)
!AI-0075-1
!AI-0191-1
@drepl @xinbull<has a result with a part of type @i<T>, or one or more parameters with a part of type @i<T>, or an access to variable parameter whose designated type has a part of type @i<T>.> @dby @xinbull<for a procedure or entry, an @b<in> parameter whose nominal type has a part of type @i<T>.>
!corrigendum 7.3.2(20/3)
!AI-0075-1
!AI-0193-1
!AI-0338-1
@drepl The check is performed on each such part of type @i<T>. @dby If the nominal type of a formal parameter (or the designated nominal type of an access-to-object parameter or result) is incomplete at the point of the declaration of the callable entity, and if the completion of that incomplete type does not occur in the same declaration list as the incomplete declaration, then for purposes of the preceding rules the nominal type is considered to have no parts of type @i<T>.
!corrigendum 7.3.2(24/3)
!AI-0312-1
!AI-0429-1
@dinsa @s9<NOTES@hr 13 For a call of a primitive subprogram of type @i<NT> that is inherited from type @i<T>, the specified checks of the specific invariants of both the types @i<NT> and @i<T> are performed. For a call of a primitive subprogram of type @i<NT> that is overridden for type @i<NT>, the specified checks of the specific invariants of only type @i<NT> are performed.> @dinss
@s8<@i<Examples>>
@i<Example of a work scheduler where only urgent work can be scheduled for weekends:>
@xcode<@b<package> Work_Orders @b<is>>
@xcode< --@ft<@i< See 3.5.1 for type declarations of Level, Day, and Weekday>>>
@xcode< @b<type> Work_Order @b<is private with>
Type_Invariant =@> Day_Scheduled (Work_Order) @b<in> Weekday
@b<or else> Priority (Work_Order) = Urgent;>
@xcode< @b<function> Schedule_Work (Urgency : @b<in> Level;
To_Occur : @b<in> Day) @b<return> Work_Order @b<with> Pre =@> Urgency = Urgent @b<or else> To_Occur @b<in> Weekday;>
@xcode< @b<function> Day_Scheduled (Order : @b<in> Work_Order) @b<return> Day;>
@xcode< @b<function> Priority (Order : @b<in> Work_Order) @b<return> Level;>
@xcode< @b<procedure> Change_Priority (Order : @b<in out> Work_Order;
New_Priority : @b<in> Level; Changed : @b<out> Boolean) @b<with> Post =@> Changed = (Day_Scheduled(Order) @b<in> Weekday
@b<or else> Priority(Order) = Urgent);>
@xcode<@b<private>>
@xcode< @b<type> Work_Order @b<is record>
Scheduled : Day; Urgency : Level;
@b<end record>;>
@xcode<@b<end> Work_Orders;>
@xcode<@b<package body> Work_Orders @b<is>>
@xcode< @b<function> Schedule_Work (Urgency : @b<in> Level;
To_Occur : @b<in> Day) @b<return> Work_Order @b<is> (Scheduled =@> To_Occur, Urgency =@> Urgency);>
@xcode< @b<function> Day_Scheduled (Order : @b<in> Work_Order) @b<return> Day @b<is>
(Order.Scheduled);>
@xcode< @b<function> Priority (Order : @b<in> Work_Order) @b<return> Level @b<is>
(Order.Urgency);>
@xcode< @b<procedure> Change_Priority (Order : @b<in out> Work_Order;
New_Priority : @b<in> Level; Changed : @b<out> Boolean) @b<is> @b<begin>
--@ft<@i< Ensure type invariant is not violated>> @b<if> Order.Urgency = Urgent @b<or else> (Order.Scheduled @b<in> Weekday) @b<then>
Changed := True; Order.Urgency := New_Priority;
@b<else>
Changed := False;
@b<end if>; @b<end> Change_Priority;>
@xcode<@b<end> Work_Orders;>
!corrigendum 7.3.3(0)
!AI-0265-1
!AI-0272-1
!AI-0324-1
!AI-0332-1
!AI-0396-1
!AI-0397-1
!AI-0419-1
@dinsc
For a private type or private extension (including a generic formal type), the following language-defined assertion aspect may be specified with an @fa<aspect_specification> (see 13.1.1):
@xhang<@xterm<Default_Initial_Condition>This aspect shall be specified by an @fa<expression>, called a @i<default initial condition expression>. Default_Initial_Condition may be specified on a @fa<private_type_declaration>, a @fa<private_extension_declaration>, a @fa<formal_private_type_definition>, or a @fa<formal_derived_type_definition>. The Default_Initial_Condition aspect is not inherited, but its effects are additive, as defined below.>
@s8<@i<Name Resolution Rules>>
The expected type for a default initial condition expression is any boolean type.
Within a default initial condition expression associated with a declaration for a type T, a name that denotes the declaration is interpreted as a current instance of a notional (nonabstract) formal derived type NT with ancestor T, that has directly visible primitive operations.
@s8<@i<Legality Rules>>
The Default_Initial_Condition aspect shall not be specified for a type whose partial view has unknown discriminants, whether explicitly declared or inherited.
@s8<@i<Static Semantics>>
If the Default_Initial_Condition aspect is specified for a type T, then the default initial condition expression applies to T and to all descendants of T.
@s8<@i<Dynamic Semantics>>
If one or more default initial condition expressions apply to a (nonabstract) type T, then a default initial condition check is performed after successful initialization of an object of type T by default (see 3.3.1). In the case of a controlled type, the check is performed after the call to the type's Initialize procedure (see 7.6).
If performing checks is required by the Default_Initial_Condition assertion policy (see 11.4.2) in effect at the point of the corresponding @fa<aspect_specification> applicable to a given type, then the respective default initial condition expression is considered enabled.
The default initial condition check consists of the evaluation of each enabled default initial condition expression that applies to T. Any operations within such an expression that were resolved as primitive operations of the (notional) formal derived type NT, are in the evaluation of the expression resolved as for a formal derived type in an instance with T as the actual type for NT (see 12.5.1). These evaluations, if there are more than one, are performed in an arbitrary order. If any of these evaluate to False, Assertions.Assertion_Error is raised at the point of the object initialization.
For a generic formal type T, default initial condition checks performed are as determined by the actual type, along with any default initial condition of the formal type itself.
@s8<@i<Implementation Permissions>>
Implementations may extend the syntax or semantics of the Default_Initial_Condition aspect in an implementation-defined manner.
@s9<NOTES@hr For an example of the use of this aspect, see the Vector container definition in A.18.2.>
!corrigendum 7.3.4(0)
!AI-0187-1
!AI-0272-1
!AI-0285-1
!AI-0324-1
!AI-0388-1
!AI-0405-1
@dinsc
Certain characteristics of an object of a given type are unchanged by most of the primitive operations of the type. Such characteristics are called @i<stable properties> of the type.
@s8<@i<Static Semantics>>
A @i<property function> of type @i<T> is a function with a single parameter of type @i<T> or of a class-wide type that covers @i<T>.
A @i<type property aspect definition> is a list of @fa<name>s written in the syntax of a @fa<positional_array_aggregate>. A @i<subprogram property aspect definition> is a list of @fa<name>s, each optionally preceded by reserved word @b<not>, also written in the syntax of a @fa<positional_array_aggregate>.
For a nonformal private type, nonformal private extension, or full type that does not have a partial view, the following language-defined aspects may be specified with an @fa<aspect_specification> (see 13.1.1):
@xhang<@xterm<Stable_Properties>This aspect
shall be specified by a type property aspect definition; each @fa<name> shall statically denote a single property function of the type. This aspect defines the @i<specific stable property functions> of the associated type.>
@xhang<@xterm<Stable_Properties'Class>This aspect
shall be specified by a type property aspect definition; each @fa<name> shall statically denote a single property function of the type. This aspect defines the @i<class-wide stable property functions> of the associated type. Unlike most class-wide aspects, Stable_Properties'Class is not inherited by descendant types and subprograms, but the enhanced class-wide postconditions are inherited in the normal manner.>
The specific and class-wide stable properties of a type together comprise the stable properties of the type.
For a primitive subprogram, the following language-defined aspects may be specified with an @fa<aspect_specification> (see 13.1.1):
@xhang<@xterm<Stable_Properties>This aspect
shall be specified by a subprogram property aspect definition; each @fa<name> shall statically denote a single property function of a type for which the associated subprogram is primitive.>
@xhang<@xterm<Stable_Properties'Class>This aspect
shall be specified by a subprogram property aspect definition; each @fa<name> shall statically denote a single property function of a tagged type for which the associated subprogram is primitive. Unlike most class-wide aspects, Stable_Properties'Class is not inherited by descendant subprograms, but the enhanced class-wide postconditions are inherited in the normal manner.>
@s8<@i<Legality Rules>>
A stable property function of a type @i<T> shall have a nonlimited return type and shall be:
@xbullet<a primitive function with a single parameter of mode @b<in> of type @i<T>; or>
@xbullet<a function that is declared immediately within the declarative region in which an ancestor type of @i<T> is declared and has a single parameter of mode @b<in> of a class-wide type that covers @i<T>.>
In a subprogram property aspect definition for a subprogram @i<S>:
@xbullet<all or none of the items shall be preceded by @b<not>;>
@xbullet<any property functions mentioned after @b<not> shall be a stable property function of a type for which @i<S> is primitive.>
If a @fa<subprogram_renaming_declaration> declares a primitive subprogram of a type @i<T>, then the renamed callable entity shall also be a primitive subprogram of type @i<T> and the two primitive subprograms shall have the same specific stable property functions and the same class-wide stable property functions (see below).
@s8<@i<Static Semantics>>
For a primitive subprogram @i<S> of a type @i<T>, the specific stable property functions of @i<S> for type @i<T> are:
@xbullet<if @i<S> has an aspect Stable_Properties specified that does not include @b<not>, those functions denoted in the aspect Stable_Properties for @i<S> that have a parameter of @i<T> or @i<T>'Class;>
@xbullet<if @i<S> has an aspect Stable_Properties specified that includes @b<not>, those functions denoted in the aspect Stable_Properties for @i<T>, excluding those denoted in the aspect Stable_Properties for @i<S>;>
@xbullet<if @i<S> does not have an aspect Stable_Properties, those functions denoted in the aspect Stable_Properties for @i<T>, if any.>
A similar definition applies for class-wide stable property functions by replacing aspect Stable_Properties with aspect Stable_Properties'Class in the above definition.
The @i<explicit> specific postcondition expression for a subprogram @i<S> is the @fa<expression> directly specified for @i<S> with the Post aspect. Similarly, the @i<explicit> class-wide postcondition expression for a subprogram @i<S> is the @fa<expression> directly specified for @i<S> with the Post'Class aspect.
For a primitive subprogram @i<S> of a type @i<T> that has a parameter @i<P> of type @i<T>, the parameter is @i<excluded from stable property checks> if: @xbullet<@i<S> is a stable property function of @i<T>;> @xbullet<@i<P> has mode @b<out>;> @xbullet<the Global aspect of @i<S> is @b<null>, and @i<P> has mode @b<in> and the mode is not overridden by a global aspect.>
For every primitive subprogram @i<S> of a type @i<T> that is not an abstract subprogram or null procedure, the specific postcondition expression of @i<S> is modified to include expressions of the form @fc<@i<F>(@i<P>) = @i<F>(@i<P>)'Old>, all @b<and>ed with each other and any explicit specific postcondition expression, with one such equality included for each specific stable property function @i<F> of @i<S> for type @i<T> that does not occur in the explicit specific postcondition expression of @i<S>, and @i<P> is each parameter of @i<S> that has type @i<T> and is not excluded from stable property checks. The resulting specific postcondition expression of @i<S> is used in place of the explicit specific postcondition expression of @i<S> when interpreting the meaning of the postcondition as defined in 6.1.1.
For every primitive subprogram @i<S> of a type @i<T>, the class-wide postcondition expression of @i<S> is modified to include expressions of the form @fc<@i<F>(@i<P>) = @i<F>(@i<P>)'Old>, all @b<and>ed with each other and any explicit class-wide postcondition expression, with one such equality included for each class-wide stable property function @i<F> of @i<S> for type @i<T> that does not occur in any class-wide postcondition expression that applies to @i<S>, and @i<P> is each parameter of @i<S> that has type @i<T> and is not excluded from stable property checks. The resulting class-wide postcondition expression of @i<S> is used in place of the explicit class-wide postcondition expression of @i<S> when interpreting the meaning of the postcondition as defined in 6.1.1.
The equality operation that is used in the aforementioned equality expressions is as described in the case of an individual membership test whose @fa<membership_choice> is a @i<choice_>@fa<simple_expression> (see 4.5.2).
The Post expression additions described above are enabled or disabled depending on the Post assertion policy that is in effect at the point of declaration of the subprogram @i<S>. A similar rule applies to the Post'Class expression additions.
@xindent<@s9<NOTES@hr 14 For an example of the use of these aspects, see the Vector container definition in A.18.2.>>
!corrigendum 7.5(2.1/3)
!AI-0172-1
!AI-0236-1
!AI-0317-1
@drepl In the following contexts, an @fa<expression> of a limited type is not permitted unless it is an @fa<aggregate>, a @fa<function_call>, a parenthesized @fa<expression> or @fa<qualified_expression> whose operand is permitted by this rule, or a @fa<conditional_expression> all of whose @i<dependent_>@fa<expression>s are permitted by this rule: @dby In the following contexts, an @fa<expression> of a limited type is permitted only if each of its operative constituents is newly constructed (see 4.4):
!corrigendum 8.1(2.1/4)
!AI-0061-1
!AI-0236-1
!AI-0308-1
@dinsa @xbullet<an @fa<access_definition>;> @dinss @xbullet<an @fa<iterated_component_association>;> @xbullet<an @fa<iterated_element_association>;> @xbullet<a @fa<quantified_expression>;> @xbullet<a @fa<declare_expression>;>
!corrigendum 8.5.1(4.6/2)
!AI-0287-1
!AI-0401-1
@drepl @xbullet<otherwise, the subtype of the @i<object_>@fa<name> shall exclude null. In addition to the places where Legality Rules normally apply (see 12.3), this rule applies also in the private part of an instance of a generic unit.> @dby @xbullet<if the @i<object_>@fa<name> statically denotes a call of a generic formal function of @i<G>, then the declaration of the result of that function shall have a @fa<null_exclusion>.>
In the case where the @i<object_>@fa<name> is a @fa<qualified_expression> with a nominal subtype @i<S> and whose @fa<expression> is a @fa<name> that denotes an object @i<Q>:
@xbullet<if @i<S> is an elementary subtype, then:> @xinbull<@i<Q> shall be a constant other than a dereference of an access type; or> @xinbull<the nominal subtype of @i<Q> shall be statically compatible with @i<S>; or> @xinbull<@i<S> shall statically match the base subtype of its type if scalar, or the first subtype of its type if an access type.> @xbullet<if @i<S> is a composite subtype, then @i<Q> shall be known to be constrained or @i<S> shall statically match the first subtype of its type.>
!corrigendum 8.6(17.1/4)
!AI-0324-1
!AI-0427-1
@drepl @xindent<Within an @fa<aspect_specification> for a type or subtype, the current instance represents a value of the type; it is not an object. The nominal subtype of this value is given by the subtype itself (the first subtype in the case of a @fa<type_declaration>), prior to applying any predicate specified directly on the type or subtype. If the type or subtype is by-reference, the associated object with the value is the object associated (see 6.2) with the execution of the usage name.> @dby @xindent<Within an @fa<aspect_specification> for a type or subtype, the current instance represents a value of the type; it is not an object. Unless otherwise specified, the nominal subtype of this value is given by the subtype itself (the first subtype in the case of a @fa<type_declaration>), prior to applying any predicate specified directly on the type or subtype. If the type or subtype is by-reference, the associated object of the value is the object associated (see 6.2) with the evaluation of the usage name.>
!corrigendum 9(1/3)
!AI-0119-1
!AI-0330-1
@drepl The execution of an Ada program consists of the execution of one or more @i<tasks>. Each task represents a separate thread of control that proceeds independently and concurrently between the points where it @i<interacts> with other tasks. The various forms of task interaction are described in this clause, and include: @dby The execution of an Ada program consists of the execution of one or more @i<tasks>. Each task represents a separable activity that proceeds independently and concurrently between the points where it @i<interacts> with other tasks. A single task, when within the context of a parallel construct, can represent multiple @i<logical threads of control> which can proceed in parallel; in other contexts, each task represents one logical thread of control.
!corrigendum 9.5(17/3)
!AI-0064-2
!AI-0247-1
!AI-0267-1
!AI-0319-1
!AI-0374-2
!AI-0396-1
!AI-0399-1
@dinsa In addition to the places where Legality Rules normally apply (see 12.3), these rules also apply in the private part of an instance of a generic unit. @dinss @s8<@i<Static Semantics>> For a program unit, task entry, formal package, formal subprogram, formal object of an anonymous access-to-subprogram type, enumeration literal, and for a subtype (including a formal subtype), the following language-defined operational aspect is defined:
@xhang<@xterm<Nonblocking> This aspect specifies the blocking restriction for the entity; it shall be specified by a static Boolean expression. The @fa<aspect_definition> can be omitted from the specification of this aspect; in that case, the aspect for the entity is True.>
@xindent<The Nonblocking aspect may be specified for all entities for which it is defined, except for protected operations and task entries. In particular, Nonblocking may be specified for generic formal parameters.>
@xindent<When aspect Nonblocking is False for an entity, the entity might contain a potentially blocking operation; such an entity @i<allows blocking>. If the aspect is True for an entity, the entity is said to be @i<nonblocking>.>
@xindent<For a generic instantiation and entities declared within such an instance, the aspect is determined by the Nonblocking aspect for the corresponding entity of the generic unit, @b<and>ed with the Nonblocking aspects of the actual generic parameters @i<used> by the entity. If the aspect is directly specified for an instance, the specified expression shall have the same value as the Nonblocking aspect of the instance (after @b<and>ing with the aspects of the used actual parameters). In the absence of a Use_Formal aspect, all actual generic parameters are presumed to be @i<used> by an entity (see H.7.1).>
@xindent<For a (protected or task) entry, the Nonblocking aspect is False.>
@xindent<For an enumeration literal, the Nonblocking aspect is True.>
@xindent<For a predefined operator of an elementary type, the Nonblocking aspect is True. For a predefined operator of a composite type, the Nonblocking aspect of the operator is the same as the Nonblocking aspect for the type.>
@xindent<For a dereference of an access-to-subprogram type, the Nonblocking aspect of the designated subprogram is that of the access-to-subprogram type.>
@xindent<For the base subtype of a scalar (sub)type, the Nonblocking aspect is True.>
@xindent<For an inherited primitive dispatching subprogram that is null or abstract, the subprogram is nonblocking if and only if a corresponding subprogram of at least one ancestor is nonblocking. For any other inherited subprogram, it is nonblocking if and only if the corresponding subprogram of the parent is nonblocking.>
@xindent<Unless directly specified, overridings of dispatching operations inherit this aspect.>
@xindent<Unless directly specified, for a formal subtype, formal package, or formal subprogram, the Nonblocking aspect is that of the actual subtype, package, or subprogram.>
@xindent<Unless directly specified, for a non-first subtype @i<S>, the Nonblocking aspect is that of the subtype identified in the subtype_indication defining @i<S>; unless directly specified for the first subtype of a derived type, the Nonblocking aspect is that of the ancestor subtype.>
@xindent<Unless directly specified, for any other program unit, first subtype, or formal object, the Nonblocking aspect of the entity is determined by the Nonblocking aspect for the innermost program unit enclosing the entity.>
@xindent<If not specified for a library unit, the Nonblocking aspect is True if the library unit is declared pure, or False otherwise.>
The following are defined to be @i<potentially blocking> operations:
@xbullet<a @fa<select_statement>;>
@xbullet<an @fa<accept_statement>;>
@xbullet<an @fa<entry_call_statement>, or a call on a procedure that renames or is implemented by an entry;>
@xbullet<a @fa<delay_statement>;>
@xbullet<an @fa<abort_statement>;>
@xbullet<task creation or activation;>
@xbullet<during a protected action, an external call on a protected subprogram (or an external requeue) with the same target object as that of the protected action.>
If a language-defined subprogram allows blocking, then a call on the subprogram is a potentially blocking operation.
@s8<@i<Legality Rules>>
A portion of program text is called a @i<nonblocking region> if it is anywhere within a parallel construct, or if the innermost enclosing program unit is nonblocking. A nonblocking region shall not contain any of the following:
@xbullet<a @fa<select_statement>;>
@xbullet<an @fa<accept_statement>;>
@xbullet<a @fa<delay_statement>;>
@xbullet<an @fa<abort_statement>;>
@xbullet<task creation or activation.>
Furthermore, a parallel construct shall neither contain a call on a callable entity for which the Nonblocking aspect is False, nor shall it contain a call on a callable entity declared within a generic unit that uses a generic formal parameter with Nonblocking aspect False (see Use_Formal aspect in H.7.1).
Finally, a nonblocking region that is outside of a parallel construct shall not contain a call on a callable entity for which the Nonblocking aspect is False, unless the region is within a generic unit and the callable entity is associated with a generic formal parameter of the generic unit, or the call is within the @fa<aspect_definition> of an assertion aspect for an entity that allows blocking.
For the purposes of the above rules, an @fa<entry_body> is considered nonblocking if the immediately enclosing protected unit is nonblocking.
For a subtype for which aspect Nonblocking is True, any predicate expression that applies to the subtype shall only contain constructs that are allowed immediately within a nonblocking program unit.
A subprogram shall be nonblocking if it overrides a nonblocking dispatching operation. An entry shall not implement a nonblocking procedure. If an inherited dispatching subprogram allows blocking, then the corresponding subprogram of each ancestor shall allow blocking.
It is illegal to directly specify aspect Nonblocking for the first subtype of the full view of a type that has a partial view. If the Nonblocking aspect of the full view is inherited, it shall have the same value as that of the partial view, or have the value True.
Aspect Nonblocking shall be directly specified for the first subtype of a derived type only if it has the same value as the Nonblocking aspect of the ancestor subtype or if it is specified True. Aspect Nonblocking shall be directly specified for a nonfirst subtype @i<S> only if it has the same value as the Nonblocking aspect of the subtype identified in the @fa<subtype_indication> defining @i<S> or if it is specified True.
For an access-to-object type that is nonblocking, the Allocate, Deallocate, and Storage_Size operations on its storage pool shall be nonblocking.
For a composite type that is nonblocking:
@xbullet<All component subtypes shall be nonblocking;>
@xbullet<For a record type or extension, every call in the @fa<default_expression> of a component (including discriminants) shall call an operation that is nonblocking;>
@xbullet<For a controlled type, the Initialize, Finalize, and Adjust (if any) subprograms shall be nonblocking.>
The predefined equality operator for a composite type, unless it is for a record type or record extension and the operator is overridden by a primitive equality operator, is illegal if it is nonblocking and:
@xbullet<for a record type or record extension, the parent primitive "=" allows blocking; or>
@xbullet<some component is of a type @i<T>, and:>
@xinbull<@i<T> is a record type or record extension that has a primitive "=" that allows blocking; or>
@xinbull<@i<T> is neither a record type nor a record extension, and @i<T> has a predefined "=" that allows blocking.>
In a generic instantiation:
@xbullet<the actual subprogram corresponding to a nonblocking formal subprogram shall be nonblocking (an actual that is an entry is not permitted in this case);>
@xbullet<the actual subtype corresponding to a nonblocking formal subtype shall be nonblocking;>
@xbullet<the actual object corresponding to a formal object of a nonblocking access-to-subprogram type shall be of a nonblocking access-to-subprogram type;>
@xbullet<the actual instance corresponding to a nonblocking formal package shall be nonblocking.>
In addition to the places where Legality Rules normally apply (see 12.3), the above rules also apply in the private part of an instance of a generic unit.
!corrigendum 9.5.1(18)
!AI-0064-2
!AI-0247-1
@drepl Certain language-defined subprograms are potentially blocking. In particular, the subprograms of the language-defined input-output packages that manipulate files (implicitly or explicitly) are potentially blocking. Other potentially blocking subprograms are identified where they are defined. When not specified as potentially blocking, a language-defined subprogram is nonblocking. @dby During a protected action, a call on a subprogram whose body contains a potentially blocking operation is a bounded error. If the bounded error is detected, Program_Error is raised; otherwise, the call proceeds normally.
!corrigendum 9.6(10)
!AI-0241-1
!AI-0302-1
@drepl @xcode< @b<package> Ada.Calendar @b<is>
@b<type> Time @b<is private>;>
@dby @xcode< @b<package> Ada.Calendar
@b<with> Nonblocking, Global =@> @b<in out synchronized> @b<is> @b<type> Time @b<is private>;>
!corrigendum 9.6.1(2/2)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<package> Ada.Calendar.Time_Zones @b<is>> @dby @xcode<@b<package> Ada.Calendar.Time_Zones
@b<with> Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum 9.6.1(8/2)
!AI-0241-1
!AI-0302-1
@drepl @xcode< @b<package> Ada.Calendar.Arithmetic @b<is>> @dby @xcode< @b<package> Ada.Calendar.Arithmetic
@b<with> Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum 9.6.1(15/2)
!AI-0241-1
!AI-0302-1
@drepl @xcode< @b<with> Ada.Calendar.Time_Zones; @b<package> Ada.Calendar.Formatting @b<is>> @dby @xcode< @b<with> Ada.Calendar.Time_Zones; @b<package> Ada.Calendar.Formatting
@b<with> Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum 9.6.1(35/2)
!AI-0336-1
!AI-0347-1
@dinsa @xcode< @b<function> Image (Date : Time;
Include_Time_Fraction : Boolean := False; Time_Zone : Time_Zones.Time_Offset := 0) @b<return> String;>
@dinst @xcode< @b<function> Local_Image (Date : Time;
Include_Time_Fraction : Boolean := False)
@b<return> String @b<is> (Image (Date, Include_Time_Fraction,
Time_Zones.Local_Time_Offset (Date)));>
!corrigendum 9.10(1/3)
!AI-0119-1
!AI-0363-1
@drepl If two different objects, including nonoverlapping parts of the same object, are @i<independently addressable>, they can be manipulated concurrently by two different tasks without synchronization. Any two nonoverlapping objects are independently addressable if either object is specified as independently addressable (see C.6). Otherwise, two nonoverlapping objects are independently addressable except when they are both parts of a composite object for which a nonconfirming value is specified for any of the following representation aspects: (record) Layout, Component_Size, Pack, Atomic, or Convention; in this case it is unspecified whether the parts are independently addressable. @dby If two different objects, including nonoverlapping parts of the same object, are @i<independently addressable>, they can be manipulated concurrently by two different logical threads of control without synchronization, unless both are subcomponents of the same full access object, and either is nonatomic (see C.6). Any two nonoverlapping objects are independently addressable if either object is specified as independently addressable (see C.6). Otherwise, two nonoverlapping objects are independently addressable except when they are both parts of a composite object for which a nonconfirming value is specified for any of the following representation aspects: (record) Layout, Component_Size, Pack, Atomic, or Convention; in this case it is unspecified whether the parts are independently addressable.
!corrigendum 9.10(15)
!AI-0267-1
!AI-0298-1
@drepl Aspect Atomic or aspect Atomic_Components may also be specified to ensure that certain reads and updates are sequential @emdash see C.6. @dby Two actions that are not sequential are defined to be @i<concurrent> actions.
Two actions are defined to @i<conflict> if one action assigns to an object, and the other action reads or assigns to a part of the same object (or of a neighboring object if the two are not independently addressable). The action comprising a call on a subprogram or an entry is defined to @i<potentially conflict> with another action if the Global aspect (or Global'Class aspect in the case of a dispatching call) of the called subprogram or entry is such that a conflicting action would be possible during the execution of the call. Similarly, two calls are considered to potentially conflict if they each have Global (or Global'Class in the case of a dispatching call) aspects such that conflicting actions would be possible during the execution of the calls. Finally, two actions that conflict are also considered to potentially conflict.
A @i<synchronized> object is an object of a task or protected type, an atomic object (see C.6), a suspension object (see D.10), or a synchronous barrier (see D.10.1). Operations on such objects are necessarily sequential with respect to one another, and hence are never considered to conflict.
@s8<@i<Erroneous Execution>>
The execution of two concurrent actions is erroneous if the actions make conflicting uses of a shared variable (or neighboring variables that are not independently addressable).
!corrigendum 9.10.1(0)
!AI-0267-1
!AI-0294-1
!AI-0298-1
!AI-0344-1
!AI-0427-1
@dinsc
This subclause determines what checks are performed relating to possible concurrent conflicting actions (see 9.10).
@s8<@i<Syntax>>
The form of a @fa<pragma> Conflict_Check_Policy is as follows:
@xindent<@ @ @b<pragma> Conflict_Check_Policy (@i<policy_>@fa<identifier>[, @i<policy_>@fa<identifier>]);>
A @fa<pragma> Conflict_Check_Policy is allowed only immediately within a @fa<declarative_part>, a @fa<package_specification>, or as a configuration pragma.
@s8<@i<Legality Rules>>
Each @i<policy_>@fa<identifier> shall be one of No_Parallel_Conflict_Checks, Known_Parallel_Conflict_Checks, All_Parallel_Conflict_Checks, No_Tasking_Conflict_Checks, Known_Tasking_Conflict_Checks, All_Tasking_Conflict_Checks, No_Conflict_Checks, Known_Conflict_Checks, All_Conflict_Checks, or an implementation-defined conflict check policy. If two @i<policy_>@fa<identifier>s are given, one shall include the word Parallel and one shall include the word Tasking. If only one @i<policy_>@fa<identifier> is given, it shall not include the word Parallel or Tasking.
A @fa<pragma> Conflict_Check_Policy given in a @fa<declarative_part> or immediately within a @fa<package_specification> applies from the place of the pragma to the end of the innermost enclosing declarative region. The region for a @fa<pragma> Conflict_Check_Policy given as a configuration pragma is the declarative region for the entire compilation unit (or units) to which it applies.
If a @fa<pragma> Conflict_Check_Policy applies to a @fa<generic_instantiation>, then the @fa<pragma> Conflict_Check_Policy applies to the entire instance.
If multiple Conflict_Check_Policy pragmas apply to a given construct, the conflict check policy is determined by the one in the innermost enclosing region. If no Conflict_Check_Policy pragma applies to a construct, the policy is (All_Parallel_Conflict_Checks, No_Tasking_Conflict_Checks) (see below).
Certain potentially conflicting actions are disallowed according to which conflict check policies apply at the place where the action or actions occur, as follows:
@xhang<@xterm<No_Parallel_Conflict_Checks> This policy imposes no restrictions on concurrent actions arising from parallel constructs.>
@xhang<@xterm<No_Tasking_Conflict_Checks> This policy imposes no restrictions on concurrent actions arising from tasking constructs.>
@xhang<@xterm<Known_Parallel_Conflict_Checks> If this policy applies to two concurrent actions appearing within parallel constructs, they are disallowed if they are known to denote the same object (see 6.4.1) with uses that conflict. For the purposes of this check, any parallel loop may be presumed to involve multiple concurrent iterations. Also, for the purposes of deciding whether two actions are concurrent, it is enough for the logical threads of control in which they occur to be concurrent at any point in their execution, unless all of the following are true:>
@xinbull<the shared object is volatile;>
@xinbull<the two logical threads of control are both known to also refer to a shared synchronized object; and>
@xinbull<each thread whose potentially conflicting action updates the shared volatile object, also updates this shared synchronized object.>
@xhang<@xterm<Known_Tasking_Conflict_Checks> If this policy applies to two concurrent actions appearing within the same compilation unit, at least one of which appears within a task body but not within a parallel construct, they are disallowed if they are known to denote the same object (see 6.4.1) with uses that conflict, and neither potentially signals the other (see 9.10). For the purposes of this check, any named task type may be presumed to have multiple instances. Also, for the purposes of deciding whether two actions are concurrent, it is enough for the tasks in which they occur to be concurrent at any point in their execution, unless all of the following are true:>
@xinbull<the shared object is volatile;>
@xinbull<the two tasks are both known to also refer to a shared synchronized object; and>
@xinbull<each task whose potentially conflicting action updates the shared volatile object, also updates this shared synchronized object.>
@xhang<@xterm<All_Parallel_Conflict_Checks> This policy includes the restrictions imposed by the Known_Parallel_Conflict_Checks policy, and in addition disallows a parallel construct from reading or updating a variable that is global to the construct, unless it is a synchronized object, or unless the construct is a parallel loop, and the global variable is a part of a component of an array denoted by an indexed component with at least one index expression that statically denotes the loop parameter of the @fa<loop_parameter_specification> or the chunk parameter of the parallel loop.>
@xhang<@xterm<All_Tasking_Conflict_Checks> This policy includes the restrictions imposed by the Known_Tasking_Conflict_Checks policy, and in addition disallows a task body from reading or updating a variable that is global to the task body, unless it is a synchronized object.>
@xhang<@xterm<No_Conflict_Checks, Known_Conflict_Checks, All_Conflict_Checks> These are shorthands for (No_Parallel_Conflict_Checks, No_Tasking_Conflict_Checks), (Known_Parallel_Conflict_Checks, Known_Tasking_Conflict_Checks), and (All_Parallel_Conflict_Checks, All_Tasking_Conflict_Checks), respectively.>
@s8<@i<Static Semantics>>
For a subprogram, the following language-defined representation aspect may be specified:
@xhang<@xterm<Parallel_Calls> The Parallel_Calls aspect is of type Boolean. The specified value shall be static. The Parallel_Calls aspect of an inherited primitive subprogram is True if Parallel_Calls is True either for the corresponding subprogram of the progenitor type or for any other inherited subprogram that it overrides. If not specified or inherited as True, the Parallel_Calls aspect of a subprogram is False.>
@xindent<Specifying the Parallel_Calls aspect to be True for a subprogram indicates that the subprogram can be safely called in parallel. Conflict checks (if required by the Conflict_Check_Policy in effect) are made on the subprogram assuming that multiple concurrent calls exist. Such checks need not be repeated at each call of the subprogram in a parallel iteration context.>
@s8<@i<Implementation Permissions>>
When the conflict check policy Known_Parallel_Conflict_Checks or All_Parallel_Conflict_Checks applies, the implementation may disallow two concurrent actions appearing within parallel constructs if the implementation can prove they will at run-time denote the same object with uses that conflict. Similarly, when the conflict check policy Known_Tasking_Conflict_Checks or All_Tasking_Conflict_Checks applies, the implementation may disallow two concurrent actions, at least one of which appears within a task body but not within a parallel construct, if the implementation can prove they will at run-time denote the same object with uses that conflict.
!corrigendum 11.4.1(2/2)
!AI-0241-1
!AI-0302-1
!AI-0399-1
@drepl @xcode<@b<with> Ada.Streams; @b<package> Ada.Exceptions @b<is>
@b<pragma> Preelaborate(Exceptions); @b<type> Exception_Id @b<is private>; @b<pragma> Preelaborable_Initialization(Exception_Id); Null_Id : @b<constant> Exception_Id; @b<function> Exception_Name(Id : Exception_Id) @b<return> String; @b<function> Wide_Exception_Name(Id : Exception_Id) @b<return> Wide_String; @b<function> Wide_Wide_Exception_Name(Id : Exception_Id)
@b<return> Wide_Wide_String;>
@dby @xcode<@b<with> Ada.Streams; @b<package> Ada.Exceptions
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is> @b<type> Exception_Id @b<is private>
@b<with> Preelaborable_Initialization;
Null_Id : @b<constant> Exception_Id; @b<function> Exception_Name(Id : Exception_Id) @b<return> String; @b<function> Wide_Exception_Name(Id : Exception_Id) @b<return> Wide_String; @b<function> Wide_Wide_Exception_Name(Id : Exception_Id)
@b<return> Wide_Wide_String;>
!corrigendum 11.4.2(9/3)
!AI-0265-1
!AI-0396-1
@drepl The @i<assertion_>@fa<aspect_mark> of a @fa<pragma> Assertion_Policy shall be one of Assert, Static_Predicate, Dynamic_Predicate, Pre, Pre'Class, Post, Post'Class, Type_Invariant, Type_Invariant'Class, or some implementation defined @fa<aspect_mark>. The @i<policy_>@fa<identifier> shall be either Check, Ignore, or some implementation-defined @fa<identifier>. @dby The @i<assertion_>@fa<aspect_mark> of a @fa<pragma> Assertion_Policy shall identify an @i<assertion aspect>, namely one of Assert, Static_Predicate, Dynamic_Predicate, Pre, Pre'Class, Post, Post'Class, Type_Invariant, Type_Invariant'Class, Default_Initial_Condition, or some implementation-defined (assertion) @fa<aspect_mark>. The @i<policy_>@fa<identifier> shall be either Check, Ignore, or some implementation-defined @fa<identifier>.
!corrigendum 11.4.2(23.1/3)
!AI-0112-1
!AI-0179-1
!AI-0265-1
!AI-0311-1
@dinsa It is a bounded error to invoke a potentially blocking operation (see 9.5.1) during the evaluation of an assertion expression associated with a call on, or return from, a protected operation. If the bounded error is detected, Program_Error is raised. If not detected, execution proceeds normally, but if it is invoked within a protected action, it might result in deadlock or a (nested) protected action. @dinss @s8<@i<Implementation Requirements>>
Any postcondition expression, type invariant expression, or default initial condition expression occurring in the specification of a language-defined unit is enabled (see 6.1.1, 7.3.2, and 7.3.3).
The evaluation of any such postcondition, type invariant, or default initial condition expression shall either yield True or propagate an exception from a @fa<raise_expression> that appears within the assertion expression.
Any precondition expression occurring in the specification of a language-defined unit is enabled (see 6.1.1) unless suppressed (see 11.5). Similarly, any predicate checks for a subtype occurring in the specification of a language-defined unit are enabled (see 3.2.4) unless suppressed.
!corrigendum 11.5(23)
!AI-0112-1
!AI-0309-1
!AI-0311-1
@dinsa @xhang<@xterm<Storage_Check> Check that evaluation of an @fa<allocator> does not require more space than is available for a storage pool. Check that the space available for a task or subprogram has not been exceeded.> @dinss @xbullet<The following check corresponds to situations in which the exception Tasking_Error is raised upon failure of a language-defined check.>
@xhang<@xterm<Tasking_Check> Check that all tasks activated successfully. Check that a called task has not yet terminated.>
@xbullet<The following checks correspond to situations in which the exception Assertion_Error is raised upon failure of a language-defined check. For a language-defined unit @i<U> associated with one of these checks in the list below, the check refers to performance of checks associated with the Pre, Static_Predicate, and Dynamic_Predicate aspects associated with any entity declared in a descendant of @i<U>, or in an instance of a generic unit which is, or is declared in, a descendant of @i<U>. Each check is associated with one or more units:>
@xhang<@xterm<Calendar_Assertion_Check>Calendar.>
@xhang<@xterm<Characters_Assertion_Check>Characters, Wide_Characters, and Wide_Wide_Characters.>
@xhang<@xterm<Containers_Assertion_Check>Containers.>
@xhang<@xterm<Interfaces_Assertion_Check>Interfaces.>
@xhang<@xterm<IO_Assertion_Check>Sequential_IO, Direct_IO, Text_IO, Wide_Text_IO, Wide_Wide_Text_IO, Storage_IO, Streams.Stream_IO, and Directories.>
@xhang<@xterm<Numerics_Assertion_Check>Numerics.>
@xhang<@xterm<Strings_Assertion_Check>Strings.>
@xhang<@xterm<System_Assertion_Check>System.>
!corrigendum 11.5(26)
!AI-0112-1
!AI-0311-1
@drepl If a given check has been suppressed, and the corresponding error situation occurs, the execution of the program is erroneous. @dby If a given check has been suppressed, and the corresponding error situation occurs, the execution of the program is erroneous. Similarly, if a precondition check has been suppressed and the evaluation of the precondition would have raised an exception, execution is erroneous.
!corrigendum 12.6(8.2/2)
!AI-0183-1
!AI-0287-1
@drepl @xbullet<if the actual matching the @fa<formal_subprogram_declaration> denotes a generic formal object of another generic unit @i<G>, and the instantiation containing the actual that occurs within the body of a generic unit @i<G> or within the body of a generic unit declared within the declarative region of the generic unit @i<G>, then the corresponding parameter or result type of the formal subprogram of @i<G> shall have a @fa<null_exclusion>;> @dby @xbullet<if the actual matching the @fa<formal_subprogram_declaration> statically denotes a generic formal subprogram of another generic unit @i<G>, and the instantiation containing the actual occurs within the body of a generic unit @i<G> or within the body of a generic unit declared within the declarative region of the generic unit @i<G>, then the corresponding parameter or result type of the formal subprogram of @i<G> shall have a @fa<null_exclusion>;>
!corrigendum 13.1(8/3)
!AI-0396-1
!AI-0407-1
@drepl A representation item @i<directly specifies> a @i<representation aspect> of the entity denoted by the @fa<local_name>, except in the case of a type-related representation item, whose @fa<local_name> shall denote a first subtype, and which directly specifies an aspect of the subtype's type. A representation item that names a subtype is either @i<subtype-specific> (Size and Alignment clauses) or @i<type-related> (all others). Subtype-specific aspects may differ for different subtypes of the same type. @dby A representation item @i<directly specifies> a @i<representation aspect> of the entity denoted by the @fa<local_name>, except in the case of a type-related representation item, whose @fa<local_name> shall denote a first subtype, and which directly specifies an aspect of the subtype's type. A representation item that names a subtype is either @i<subtype-specific> (Size, Object_Size, and Alignment clauses) or @i<type-related> (all others).
!corrigendum 13.1(9/4)
!AI-0181-1
!AI-0222-1
@drepl A representation item that directly specifies an aspect of an entity shall appear before the entity is frozen (see 13.14). In addition, a representation item that directly specifies an aspect of a subtype or type shall appear after the type is completely defined (see 3.11.1). @dby A representation item or operational item that directly specifies an aspect of an entity shall appear before the entity is frozen (see 13.14).
!corrigendum 13.1(9.1/4)
!AI-0181-1
!AI-0222-1
!AI-0396-1
@drepl An operational item that directly specifies an aspect of an entity shall appear before the entity is frozen (see 13.14). @dby A representation aspect of a subtype or type shall not be specified (whether by a representation item or an @fa<aspect_specification>) before the type is completely defined (see 3.11.1).
!corrigendum 13.1(9.3/5)
!AI-0396-1
!AI-0417-1
@drepl If a representation item, operational item, or @fa<aspect_specification> is given that directly specifies an aspect of an entity, then it is illegal to give another representation item, operational item, or @fa<aspect_specification> that directly specifies the same aspect of the entity. @dby If a representation item, operational item, library unit pragma (see J.15), or @fa<aspect_specification> is given that directly specifies an aspect of an entity, then it is illegal to give another representation item, operational item, library unit pragma, or @fa<aspect_specification> that directly specifies the same aspect of the entity.
!corrigendum 13.1(10/4)
!AI-0376-1
!AI-0427-1
@drepl For an untagged derived type, it is illegal to specify a type-related representation aspect if the parent type is a by-reference type, or has any user-defined primitive subprograms. Similarly, it is illegal to specify a nonconfirming type-related representation aspect for an untagged by-reference type after one or more types have been derived from it. @dby A @i<by-reference primitive> is a user-defined primitive subprogram for a type @i<T> that has an access result designating type @i<T>, or that has a formal parameter that is an access parameter designating type @i<T> or is aliased and of type @i<T>. It is illegal to specify a nonconfirming type-related representation aspect for an untagged type @i<T> if it is derived from a by-reference type or inherits one or more by-reference primitives, or if one or more types have been derived from @i<T> prior to the specification of the aspect and type @i<T> is a by-reference type or defines one or more by-reference primitives that are inherited by these descendants.
!corrigendum 13.1(11/3)
!AI-0396-1
!AI-0409-1
@drepl Operational and representation aspects of a generic formal parameter are the same as those of the actual. Operational and representation aspects are the same for all views of a type. Specification of a type-related representation aspect is not allowed for a descendant of a generic formal untagged type. @dby If a type-related aspect is defined for the partial view of a type, then it has the same definition for the full view of the type, except for certain Boolean-valued operational aspects where the language specifies that the partial view can have the value False even when the full view has the value True. Type-related aspects cannot be specified, and are not defined for an incomplete view of a type. Representation aspects of a generic formal parameter are the same as those of the actual. Specification of a type-related representation aspect is not allowed for a descendant of a generic formal untagged type.
!corrigendum 13.1(15.1/3)
!AI-0396-1
!AI-0423-1
@drepl In contrast, whether operational aspects are inherited by a derived type depends on each specific aspect; unless specified, an operational aspect is not inherited. When operational aspects are inherited by a derived type, aspects that were directly specified by @fa<aspect_specification>s or operational items that are visible at the point of the derived type declaration, or (in the case where the parent is derived) that were inherited by the parent type from the grandparent type are inherited. An inherited operational aspect is overridden by a subsequent @fa<aspect_specification> or operational item that specifies the same aspect of the type. @dby In contrast, whether type-related operational aspects are inherited by a derived type depends on each specific aspect; unless specified, an operational aspect is not inherited. When type-related operational aspects are inherited by a derived type, aspects that were directly specified by @fa<aspect_specification>s or operational items that are visible at any point within the immediate scope of the derived type declaration, or (in the case where the parent is derived) that were inherited by the parent type from the grandparent type, are inherited. An inherited operational aspect is overridden by an @fa<aspect_specification> or operational item that specifies the same aspect of the type.
When a type-related operational aspect is inherited, the rules for inheritance depend on the nature of the aspect (see 13.1.1). Unless otherwise specified for a given aspect, these rules are as follows:
@xbullet<For an operational aspect that is a value, the inherited aspect has the same value;>
@xbullet<For an operational aspect that is a @fa<name>:>
@xinbull<if the @fa<name> denotes one or more primitive subprograms of the type, the inherited aspect is a @fa<name> that denotes the corresponding primitive subprogram(s) of the derived type;>
@xinbull<otherwise, the inherited aspect is a @fa<name> that denotes the same entity or entities as the original aspect;>
@xbullet<For an operational aspect that is an identifier specific to the aspect, the inherited aspect is the same identifier;>
@xbullet<For an operational aspect that is an @fa<expression> or an @fa<aggregate>, the inherited aspect is a corresponding @fa<expression> or @fa<aggregate> where each @fa<name>, value, and identifier follows these same rules for inheritance.>
!corrigendum 13.1.1(4/3)
!AI-0187-1
!AI-0285-1
!AI-0373-1
@drepl @xindent<@fa<aspect_definition>@fa<@ ::=@ >@fa<name> | @fa<expression> | @fa<identifier>> @dby @xindent<@fa<aspect_definition>@fa<@ ::=@ >@hr @ @ @ @ @fa<name>@ |@ @fa<expression>@ |@ @fa<identifier>@hr @ @ |@ @fa<aggregate>@ |@ @fa<global_aspect_definition>>
!corrigendum 13.1.1(11/3)
!AI-0373-1
!AI-0427-1
@drepl The usage names in an @fa<aspect_definition> are not resolved at the point of the associated declaration, but rather are resolved at the end of the immediately enclosing declaration list. @dby The usage names in an @fa<aspect_definition> associated with a declaration are not resolved at the point of the associated declaration, but rather are resolved at the end of the immediately enclosing declaration list, or in the case of the declaration of a library unit, at the end of the visible part of the entity.
!corrigendum 13.1.1(12/3)
!AI-0180-1
!AI-0220-1
@drepl If the associated declaration is for a subprogram or entry, the names of the formal parameters are directly visible within the @fa<aspect_definition>, as are certain attributes, as specified elsewhere in this International Standard for the identified aspect. If the associated declaration is a @fa<type_declaration>, within the @fa<aspect_definition> the names of any components are directly visible, and the name of the first subtype denotes the current instance of the type (see 8.6). If the associated declaration is a @fa<subtype_declaration>, within the @fa<aspect_definition> the name of the new subtype denotes the current instance of the subtype. @dby If the associated declaration is for a subprogram, entry, or access-to-subprogram type, the names of the formal parameters are directly visible within the @fa<aspect_definition>, as are certain attributes, as specified elsewhere in this document for the identified aspect. If the associated declaration is a @fa<type_declaration>, within the @fa<aspect_definition> the names of any visible components, protected subprograms, and entries are directly visible, and the name of the first subtype denotes the current instance of the type (see 8.6). If the associated declaration is a @fa<subtype_declaration>, within the @fa<aspect_definition> the name of the new subtype denotes the current instance of the subtype.
!corrigendum 13.1.1(17/3)
!AI-0064-2
!AI-0194-1
!AI-0380-1
!AI-0407-1
@drepl There are no language-defined aspects that may be specified on a @fa<renaming_declaration>, a @fa<generic_formal_parameter_declaration>, a @fa<subunit>, a @fa<package_body>, a @fa<task_body>, a @fa<protected_body>, or a @fa<body_stub> other than a @fa<subprogram_body_stub>. @dby Unless otherwise specified for a specific aspect, a language-defined aspect cannot be specified on a @fa<renaming_declaration> or a @fa<generic_formal_parameter_declaration>.
!corrigendum 13.1.1(18.2/4)
!comment This was the original paragraph number, AI12-0396-1 changed it.
!comment We have to use the original number here so that a conflict is
!comment properly detected.
!AI-0206-1
!AI-0419-1
@drepl Certain type-related aspects are defined to be @i<nonoverridable>; all such aspects are specified using an @fa<aspect_definition> that is a @fa<name>. @dby Certain type-related aspects are defined to be @i<nonoverridable>; all such aspects are inherited by derived types according to the rules given in 13.1. Any legality rule associated with a nonoverridable aspect is re-checked for the derived type, if the derived type is not abstract. Certain type-related and subtype-specific aspects are defined to be @i<additive>; such aspects are not inherited, but they can @i<apply> to the types derived from, or the subtypes based on, the original type or subtype, as defined for each such aspect. Finally, certain type-related aspects are @i<implicitly composed>; such aspects are not inherited, but rather a default implementation for a derived type is provided, as defined for each such aspect, based on that of its parent type, presuming the aspect for the parent type is available where the derived type is declared, plus those of any new components added as part of a type extension.
!corrigendum 13.1.1(18.3/4)
!comment This was the original paragraph number, AI12-0396-1 changed it.
!comment We have to use the original number here so that a conflict is
!comment properly detected.
!AI-0206-1
!AI-0211-1
!AI-0396-1
@drepl If a nonoverridable aspect is directly specified for a type @i<T>, then any explicit specification of that aspect for any other descendant of @i<T> shall be @i<confirming>; that is, the specified @fa<name> shall @i<match> the inherited aspect, meaning that the specified @fa<name> shall denote the same declarations as would the inherited @fa<name>. @dby If a nonoverridable aspect is directly specified for a type @i<T>, then any explicit specification of that aspect for any descendant of @i<T> (other than @i<T> itself) shall be @i<confirming>. In the case of an aspect that is a @fa<name>, this means that the specified @fa<name> shall @i<match> the inherited aspect in the sense that it shall denote the same declarations as would the inherited @fa<name>. Similarly, for an aspect that is an @fa<expression> or an @fa<aggregate>, confirming means the defining @fa<expression> is fully conformant (see 6.3.1) with the defining @fa<expression> for the inherited aspect, with the added rule that an identifier that is specific to the aspect is the same as the corresponding identifier in the inherited aspect.
!corrigendum 13.1.1(18.6/4)
!comment This was the original paragraph number, AI12-0211-1 changed it.
!comment We have to use the original number here so that a conflict is
!comment properly detected.
!AI-0206-1
!AI-0256-1
!AI-0373-1
@drepl The Default_Iterator, Iterator_Element, Implicit_Dereference, Constant_Indexing, and Variable_Indexing aspects are nonoverridable. @dby The Default_Iterator, Iterator_Element, Implicit_Dereference, Constant_Indexing, Variable_Indexing, Aggregate, Max_Entry_Queue_Length, and No_Controlled_Parts aspects are nonoverridable.
!corrigendum 13.7.2(2)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<generic>
@b<type> Object(<@>) @b<is limited private>;
@b<package> System.Address_To_Access_Conversions @b<is>
@b<pragma> Preelaborate(Address_To_Access_Conversions);>
@dby @xcode<@b<generic>
@b<type> Object(<@>) @b<is limited private>;
@b<package> System.Address_To_Access_Conversions
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum 13.11(17)
!AI-0319-1
!AI-0424-1
@dinsa If Storage_Pool is not specified for a type defined by an @fa<access_to_object_definition>, then the implementation chooses a standard storage pool for it in an implementation-defined manner. In this case, the exception Storage_Error is raised by an @fa<allocator> if there is not enough storage. It is implementation defined whether or not the implementation provides user-accessible names for the standard pool type(s). @dinst The type(s) of the standard pool(s), and the primitive Allocate, Deallocate, and Storage_Size subprograms for the standard pool(s) are nonblocking. Concurrent invocations of these subprograms do not conflict with one another (see 9.10) when applied to standard storage pools.
!corrigendum 13.11.2(3/3)
!AI-0241-1
!AI-0302-1
!AI-0319-1
@drepl @xcode<@b<generic>
@b<type> Object(<@>) @b<is limited private>; @b<type> Name @b<is access> Object;
@b<procedure> Ada.Unchecked_Deallocation(X : @b<in out> Name)
@b<with> Convention =@> Intrinsic;
@b<pragma> Preelaborate(Ada.Unchecked_Deallocation);> @dby @xcode<@b<generic>
@b<type> Object(<@>) @b<is limited private>; @b<type> Name @b<is access> Object;
@b<procedure> Ada.Unchecked_Deallocation(X : @b<in out> Name)
@b<with> Preelaborate, Nonblocking,
Global =@> @b<in out> Name'Storage_Pool, Convention =@> Intrinsic;>
!corrigendum 13.11.4(4/3)
!AI-0356-1
!AI-0399-1
@drepl @xcode< @b<type> Root_Storage_Pool_With_Subpools @b<is>
@b<abstract new> Root_Storage_Pool @b<with private>;>
@dby @xcode< @b<type> Root_Storage_Pool_With_Subpools @b<is>
@b<abstract new> Root_Storage_Pool @b<with private> @b<with> Preelaborable_Initialization;>
!corrigendum 13.11.4(5/3)
!AI-0356-1
!AI-0399-1
@drepl @xcode< @b<type> Root_Subpool @b<is abstract tagged limited private>;> @dby @xcode< @b<type> Root_Subpool @b<is abstract tagged limited private>
@b<with> Preelaborable_Initialization;>
!corrigendum 13.13.1(9)
!AI-0293-1
!AI-0302-1
!AI-0329-1
@dinsa The Write operation appends Item to the specified stream. @dinss Three additional packages provide stream implementations that do not make use of any file operations. These packages provide the same operations, with Streams.Storage providing an abstract interface, and two child packages providing implementations of that interface. The difference is that for Streams.Storage.Bounded, the maximum storage is bounded.
The library package Ada.Streams.Storage has the following declaration:
@xcode<@b<package> Ada.Streams.Storage
@b<with> Pure, Nonblocking @b<is>>
@xcode< @b<type> Storage_Stream_Type @b<is abstract new> Root_Stream_Type @b<with private>;>
@xcode< @b<function> Element_Count (Stream : Storage_Stream_Type)
@b<return> Stream_Element_Count @b<is abstract>;>
@xcode< @b<procedure> Clear (Stream : @b<in out> Storage_Stream_Type) @b<is abstract>;>
@xcode<@b<private>
... -- @ft<@i<not specified by the language>>
@b<end> Ada.Streams.Storage;>
The library package Ada.Streams.Storage.Unbounded has the following declaration:
@xcode<@b<package> Ada.Streams.Storage.Unbounded
@b<with> Prelaborated, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
@xcode< @b<type> Stream_Type @b<is new> Storage_Stream_Type @b<with private>
@b<with> Default_Initial_Condition =@>
Element_Count (Stream_Type) = 0;>
@xcode< @b<overriding>
@b<procedure> Read (
Stream : @b<in out> Stream_Type; Item : @b<out> Stream_Element_Array; Last : @b<out> Stream_Element_Offset) @b<with> Post =@>
(@b<declare> Num_Read : @b<constant> Stream_Element_Count := Stream_Element_Count'Min (Element_Count(Stream)'Old, Item'Length); @b<begin> Last = Num_Read + Item'First - 1 @b<and> Element_Count (Stream) = Element_Count (Stream)'Old - Num_Read);>
@xcode< @b<overriding>
@b<procedure> Write (
Stream : @b<in out> Stream_Type; Item : @b<in> Stream_Element_Array) @b<with> Post =@>
Element_Count (Stream) = Element_Count (Stream)'Old + Item'Length;>
@xcode< @b<overriding>
@b<function> Element_Count (Stream : Stream_Type)
@b<return> Stream_Element_Count;>
@xcode< @b<overriding>
@b<procedure> Clear (Stream : @b<in out> Stream_Type)
@b<with> Post =@> Element_Count (Stream) = 0;>
@xcode<@b<private>
... -- @ft<@i<not specified by the language>>
@b<end> Ada.Streams.Storage.Unbounded;>
The library package Ada.Streams.Storage.Bounded has the following declaration:
@xcode<@b<package> Ada.Streams.Storage.Bounded
@b<with> Pure, Nonblocking @b<is>>
@xcode< @b<type> Stream_Type (Max_Elements : Stream_Element_Count)
@b<is new> Storage_Stream_Type @b<with private>
@b<with> Default_Initial_Condition =@>
Element_Count (Stream_Type) = 0;>
@xcode< @b<overriding>
@b<procedure> Read (
Stream : @b<in out> Stream_Type; Item : @b<out> Stream_Element_Array; Last : @b<out> Stream_Element_Offset) @b<with> Post =@>
(@b<declare> Num_Read : @b<constant> Stream_Element_Count := Stream_Element_Count'Min (Element_Count(Stream)'Old, Item'Length); @b<begin> Last = Num_Read + Item'First - 1 @b<and> Element_Count (Stream) = Element_Count (Stream)'Old - Num_Read);>
@xcode< @b<overriding>
@b<procedure> Write (
Stream : @b<in out> Stream_Type; Item : @b<in> Stream_Element_Array) @b<with> Pre =@>
Element_Count (Stream) + Item'Length <= Stream.Max_Elements @b<or else> (@b<raise> Constraint_Error),
Post =@>
Element_Count (Stream) = Element_Count (Stream)'Old + Item'Length;>
@xcode< @b<overriding>
@b<function> Element_Count (Stream : Stream_Type)
@b<return> Stream_Element_Count @b<with> Post =@> Element_Count'Result <= Stream.Max_Elements;>
@xcode< @b<overriding>
@b<procedure> Clear (Stream : @b<in out> Stream_Type)
@b<with> Post =@> Element_Count (Stream) = 0;>
@xcode<@b<private>
... -- @ft<@i<not specified by the language>>
@b<end> Ada.Streams.Storage.Bounded;>
The Element_Count functions return the number of stream elements that are available for reading from the given stream.
The Read and Write procedures behave as described for package Ada.Streams above. Stream elements are read in FIFO (first-in, first-out) order; stream elements are available for reading immediately after they are written.
The Clear procedures remove any available stream elements from the given stream.
!corrigendum 13.13.1(9.1/1)
!AI-0293-1
!AI-0329-1
@dinsa If Stream_Element'Size is not a multiple of System.Storage_Unit, then the components of Stream_Element_Array need not be aliased. @dinst @s8<@i<Implementation Advice>>
Streams.Storage.Bounded.Stream_Type objects should be implemented without implicit pointers or dynamic allocation.
!corrigendum 13.13.2(9/3)
!AI-0191-1
!AI-0419-1
@drepl For elementary types, Read reads (and Write writes) the number of stream elements implied by the Stream_Size for the type @i<T>; the representation of those stream elements is implementation defined. For composite types, the Write or Read attribute for each component is called in canonical order, which is last dimension varying fastest for an array (unless the convention of the array is Fortran, in which case it is first dimension varying fastest), and positional aggregate order for a record. Bounds are not included in the stream if @i<T> is an array type. If @i<T> is a discriminated type, discriminants are included only if they have defaults. If @i<T> is a tagged type, the tag is not included. For type extensions, the Write or Read attribute for the parent type is called, followed by the Write or Read attribute of each component of the extension part, in canonical order. For a limited type extension, if the attribute of the parent type or any progenitor type of @i<T> is available anywhere within the immediate scope of @i<T>, and the attribute of the parent type or the type of any of the extension components is not available at the freezing point of @i<T>, then the attribute of @i<T> shall be directly specified. @dby For nonderived elementary types, Read reads (and Write writes) the number of stream elements implied by the Stream_Size for the type @i<T>; the representation of those stream elements is implementation defined. For nonderived composite types, the Write or Read attribute for each component (excluding those, if any, that are not components of the nominal type of the object) is called in canonical order, which is last dimension varying fastest for an array (unless the convention of the array is Fortran, in which case it is first dimension varying fastest), and positional aggregate order for a record. Bounds are not included in the stream if @i<T> is an array type. If @i<T> is a discriminated type, discriminants are included only if they have defaults. If @i<T> is a tagged type, the tag is not included.
For type extensions, the Write or Read attribute for the parent type is called, followed by the Write or Read attribute of each component of the extension part, in canonical order. For a limited type extension, if the attribute of the parent type or any progenitor type of @i<T> is available anywhere within the immediate scope of @i<T>, and the attribute of the parent type or the type of any of the extension components is not available at the freezing point of @i<T>, then the attribute of @i<T> shall be directly specified. For untagged derived types, the Write (resp. Read) attribute invokes the corresponding attribute of the parent type, if the attribute is available for the parent type.
!corrigendum 13.13.2(37/1)
!AI-0064-2
!AI-0396-1
@dinsa In the default implementation of Read and Input for a type, End_Error is raised if the end of the stream is reached before the reading of a value of the type is completed. @dinst The Nonblocking aspect is statically True and the Global aspect is @b<null> for the default implementations of stream-oriented attributes for elementary types. For the default implementations of stream-oriented attributes for composite types, the value of the Nonblocking aspect is that of the first subtype, and the Global aspect defaults to that of the first subtype. A default implementation of a stream-oriented attribute that has the Nonblocking aspect statically True is considered a nonblocking region. The aspect Dispatching (see H.7.1) is Read(Stream) for the default implementations of the stream-oriented attributes Read, Read'Class, Input, and Input'Class; the aspect Dispatching is Write(Stream) for the default implementations of the stream-oriented attributes Write, Write'Class, Output, and Output'Class.
!corrigendum 13.14(3/4)
!AI-0155-1
!AI-0168-1
!AI-0373-1
@drepl The end of a @fa<declarative_part>, @fa<protected_body>, or a declaration of a library package or generic library package, causes @i<freezing> of each entity and profile declared within it, except for incomplete types. A @fa<proper_body>, @fa<body_stub>, or @fa<entry_body> causes freezing of each entity and profile declared before it within the same @fa<declarative_part> that is not an incomplete type; it only causes freezing of an incomplete type if the body is within the immediate scope of the incomplete type. @dby The end of a @fa<declarative_part>, @fa<protected_body>, or a declaration of a library package or generic library package, causes @i<freezing> of each entity and profile declared within it, as well as the entity itself in the case of the declaration of a library unit. A noninstance @fa<proper_body>, @fa<body_stub>, or @fa<entry_body> causes freezing of each entity and profile declared before it within the same @fa<declarative_part>.
!corrigendum 13.14(7.2/3)
!AI-0396-1
!AI-0407-1
@drepl @xbullet<At the freezing point of the entity associated with an @fa<aspect_specification>, any @fa<expression>s or @fa<name>s within the @fa<aspect_specification> cause freezing. Any static expressions within an @fa<aspect_specification> also cause freezing at the end of the immediately enclosing declaration list.> @dby @xbullet<At the freezing point of the entity associated with an @fa<aspect_specification>, any static expressions within the @fa<aspect_specification> cause freezing, as do @fa<expression>s or @fa<name>s in @fa<aspect_definition>s for representation aspects, or operational aspects that have a corresponding operational attribute. Similarly, if an @fa<aspect_definition> for an operational aspect, other than an assertion aspect, could affect the Name Resolution, Static Semantics, or Legality Rules of a subsequent construct, then any @fa<expression>s or @fa<name>s within the @fa<aspect_definition> cause freezing at the freezing point of the associated entity. Any static expressions within an @fa<aspect_specification> also cause freezing at the end of the immediately enclosing declaration list. For the purposes of this rule, if there is no declared entity associated with an @fa<aspect_specification>, the freezing point is considered to occur immediately following the @fa<aspect_specification>.>
!corrigendum 13.14(15.1/3)
!AI-0155-1
!AI-0396-1
@dinsa @xbullet<At the place where a specific tagged type is frozen, the primitive subprograms of the type are frozen. At the place where a type is frozen, any subprogram named in an @fa<attribute_definition_clause> for the type is frozen.> @dinss
Notwithstanding the rest of this subclause, freezing an incomplete view has no effect.
!corrigendum A.3.2(32.5/3)
!AI-0004-1
!AI-0263-1
@dinsa @xhang<@xterm<Is_Space> True if Item is a character with position 32 (' ') or 160 (No_Break_Space).> @dinst @xhang<@xterm<Is_NFKC> True if Item could be present in a string normalized to Normalization Form KC (as defined by Clause 21 of ISO/IEC 10646:2017); this includes all characters except those with positions 160, 168, 170, 175, 178, 179, 180, 181, 184, 185, 186, 188, 189, and 190.>
!corrigendum A.3.5(51/3)
!AI-0004-1
!AI-0263-1
@dinsa @xindent<Returns True if the Wide_Character designated by Item is categorized as @fa<separator_space>, otherwise returns False.> @dinss @xcode<@b<function> Is_NFKC (Item : Wide_Character) @b<return> Boolean;>
@xindent<Returns True if the Wide_Character designated by Item could be present in a string normalized to Normalization Form KC (as defined by Clause 21 of ISO/IEC 10646:2017), otherwise returns False.>
!corrigendum A.4.3(5)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> Ada.Strings.Maps; @b<package> Ada.Strings.Fixed @b<is>
@b<pragma> Preelaborate(Fixed);>
@dby @xcode<@b<with> Ada.Strings.Maps; @b<package> Ada.Strings.Fixed
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum A.4.4(3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> Ada.Strings.Maps; @b<package> Ada.Strings.Bounded @b<is>
@b<pragma> Preelaborate(Bounded);>
@dby @xcode<@b<with> Ada.Strings.Maps; @b<package> Ada.Strings.Bounded
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum A.4.5(3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> Ada.Strings.Maps; @b<package> Ada.Strings.Unbounded @b<is>
@b<pragma> Preelaborate(Unbounded);>
@dby @xcode<@b<with> Ada.Strings.Maps; @b<package> Ada.Strings.Unbounded
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum A.4.7(3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<package> Ada.Strings.Wide_Maps @b<is>
@b<pragma> Preelaborate(Wide_Maps);>
@dby @xcode<@b<package> Ada.Strings.Wide_Maps
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum A.4.7(46.2/2)
!AI-0302-1
!AI-0414-1
@drepl @fa<Pragma> Pure is replaced by pragma Preelaborate in Strings.Wide_Maps.Wide_Constants. @dby Aspect Pure is replaced by aspects @fc<Preelaborate, Nonblocking, Global =@> @b<in out synchronized>> in Strings.Wide_Maps.Wide_Constants.
!corrigendum A.4.8(3/2)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<package> Ada.Strings.Wide_Wide_Maps @b<is>
@b<pragma> Preelaborate(Wide_Wide_Maps);>
@dby @xcode<@b<package> Ada.Strings.Wide_Wide_Maps
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum A.4.8(50/2)
!AI-0302-1
!AI-0414-1
@drepl @fa<Pragma> Pure is replaced by pragma Preelaborate in Strings.Wide_Maps.Wide_Constants. @dby Aspect Pure is replaced by aspects @fc< Preelaborate, Nonblocking, Global =@> @b<in out synchronized>> in Strings.Wide_Wide_Maps.Wide_Wide_Constants.
!corrigendum A.4.9(7/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> Ada.Containers; @b<generic>
@b<with package> Bounded @b<is>
@b<new> Ada.Strings.Bounded.Generic_Bounded_Length (<@>);
@b<function> Ada.Strings.Bounded.Hash (Key : Bounded.Bounded_String)
@b<return> Containers.Hash_Type;
@b<pragma> Preelaborate(Ada.Strings.Bounded.Hash);> @dby @xcode<@b<with> Ada.Containers; @b<generic>
@b<with package> Bounded @b<is>
@b<new> Ada.Strings.Bounded.Generic_Bounded_Length (<@>);
@b<function> Ada.Strings.Bounded.Hash (Key : Bounded.Bounded_String)
@b<return> Containers.Hash_Type @b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized>;>
!corrigendum A.4.9(10/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> Ada.Containers; @b<function> Ada.Strings.Unbounded.Hash (Key : Unbounded_String)
@b<return> Containers.Hash_Type;
@b<pragma> Preelaborate(Ada.Strings.Unbounded.Hash);> @dby @xcode<@b<with> Ada.Containers; @b<function> Ada.Strings.Unbounded.Hash (Key : Unbounded_String)
@b<return> Containers.Hash_Type @b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized>;>
!corrigendum A.4.9(11.7/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> Ada.Containers; @b<generic>
@b<with package> Bounded @b<is>
@b<new> Ada.Strings.Bounded.Generic_Bounded_Length (<@>);
@b<function> Ada.Strings.Bounded.Hash_Case_Insensitive
(Key : Bounded.Bounded_String) @b<return> Containers.Hash_Type;
@b<pragma> Preelaborate(Ada.Strings.Bounded.Hash_Case_Insensitive);> @dby @xcode<@b<with> Ada.Containers; @b<generic>
@b<with package> Bounded @b<is>
@b<new> Ada.Strings.Bounded.Generic_Bounded_Length (<@>);
@b<function> Ada.Strings.Bounded.Hash_Case_Insensitive
(Key : Bounded.Bounded_String) @b<return> Containers.Hash_Type @b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized>;>
!corrigendum A.4.9(11.10/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> Ada.Containers; @b<function> Ada.Strings.Unbounded.Hash_Case_Insensitive
(Key : Unbounded_String) @b<return> Containers.Hash_Type;
@b<pragma> Preelaborate(Ada.Strings.Unbounded.Hash_Case_Insensitive);> @dby @xcode<@b<with> Ada.Containers; @b<function> Ada.Strings.Unbounded.Hash_Case_Insensitive
(Key : Unbounded_String) @b<return> Containers.Hash_Type @b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized>;>
!corrigendum A.4.10(7/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<generic>
@b<with package> Bounded @b<is>
@b<new> Ada.Strings.Bounded.Generic_Bounded_Length (<@>);
@b<function> Ada.Strings.Bounded.Equal_Case_Insensitive
(Left, Right : Bounded.Bounded_String) @b<return> Boolean;
@b<pragma> Preelaborate(Ada.Strings.Bounded.Equal_Case_Insensitive);> @dby @xcode<@b<generic>
@b<with package> Bounded @b<is>
@b<new> Ada.Strings.Bounded.Generic_Bounded_Length (<@>);
@b<function> Ada.Strings.Bounded.Equal_Case_Insensitive
(Left, Right : Bounded.Bounded_String) @b<return> Boolean @b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized>;>
!corrigendum A.4.10(10/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<function> Ada.Strings.Unbounded.Equal_Case_Insensitive
(Left, Right : Unbounded_String) @b<return> Boolean;
@b<pragma> Preelaborate(Ada.Strings.Unbounded.Equal_Case_Insensitive);> @dby @xcode<@b<function> Ada.Strings.Unbounded.Equal_Case_Insensitive
(Left, Right : Unbounded_String) @b<return> Boolean @b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized>;>
!corrigendum A.4.10(18/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<generic>
@b<with package> Bounded @b<is>
@b<new> Ada.Strings.Bounded.Generic_Bounded_Length (<@>);
@b<function> Ada.Strings.Bounded.Less_Case_Insensitive
(Left, Right : Bounded.Bounded_String) @b<return> Boolean;
@b<pragma> Preelaborate(Ada.Strings.Bounded.Less_Case_Insensitive);> @dby @xcode<@b<generic>
@b<with package> Bounded @b<is>
@b<new> Ada.Strings.Bounded.Generic_Bounded_Length (<@>);
@b<function> Ada.Strings.Bounded.Less_Case_Insensitive
(Left, Right : Bounded.Bounded_String) @b<return> Boolean
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized>;>
!corrigendum A.4.10(21/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<function> Ada.Strings.Unbounded.Less_Case_Insensitive
(Left, Right : Unbounded_String) @b<return> Boolean;
@b<pragma> Preelaborate(Ada.Strings.Unbounded.Less_Case_Insensitive);> @dby @xcode<@b<function> Ada.Strings.Unbounded.Less_Case_Insensitive
(Left, Right : Unbounded_String) @b<return> Boolean
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized>;>
!corrigendum A.4.12(0)
!AI-0340-1
!AI-0384-2
@dinsc A universal text buffer can be used to save and retrieve text of any language-defined string type. The types used to save and retrieve the text need not be the same.
The text buffer library packages have the following declarations:
@xcode<@b<with> Ada.Strings.UTF_Encoding.Wide_Wide_Strings; @b<package> Ada.Strings.Text_Buffers
@b<with> Pure @b<is>>
@xcode< @b<type> Text_Buffer_Count @b<is range> 0 .. @ft<@i<implementation-defined>>;>
@xcode< New_Line_Count : @b<constant> Text_Buffer_Count := @ft<@i<implementation-defined>>;>
@xcode< @b<type> Root_Buffer_Type @b<is abstract tagged private>
@b<with> Default_Initial_Condition =@>
Current_Indent (Root_Buffer_Type) = 0;>
@xcode< @b<procedure> Put (
Buffer : @b<in out> Root_Buffer_Type; Item : @b<in> String) @b<is abstract>;>
@xcode< @b<procedure> Wide_Put (
Buffer : @b<in out> Root_Buffer_Type; Item : @b<in> Wide_String) @b<is abstract>;>
@xcode< @b<procedure> Wide_Wide_Put (
Buffer : @b<in out> Root_Buffer_Type; Item : @b<in> Wide_Wide_String) @b<is abstract>;>
@xcode< @b<procedure> Put_UTF_8 (
Buffer : @b<in out> Root_Buffer_Type; Item : @b<in> UTF_Encoding.UTF_8_String) @b<is abstract>;>
@xcode< @b<procedure> Wide_Put_UTF_16 (
Buffer : @b<in out> Root_Buffer_Type; Item : @b<in> UTF_Encoding.UTF_16_Wide_String) @b<is abstract>;>
@xcode< @b<procedure> New_Line (Buffer : @b<in out> Root_Buffer_Type) @b<is abstract>;>
@xcode< Standard_Indent : @b<constant> Text_Buffer_Count := 3;>
@xcode< @b<function> Current_Indent (
Buffer : Root_Buffer_Type) @b<return> Text_Buffer_Count;>
@xcode< @b<procedure> Increase_Indent (
Buffer : @b<in out> Root_Buffer_Type; Amount : @b<in> Text_Buffer_Count := Standard_Indent) @b<with> Post'Class =@>
Current_Indent (Buffer) = Current_Indent (Buffer)'Old + Amount;>
@xcode< @b<procedure> Decrease_Indent (
Buffer : @b<in out> Root_Buffer_Type; Amount : @b<in> Text_Buffer_Count := Standard_Indent) @b<with> Pre'Class =@>
Current_Indent (Buffer) @>= Amount
@b<or else raise> Constraint_Error,
Post'Class =@>
Current_Indent (Buffer) = Current_Indent (Buffer)'Old - Amount;>
@xcode<@b<private>
... --@ft<@i< not specified by the language>>
@b<end> Ada.Strings.Text_Buffers;>
@xcode<@b<package> Ada.Strings.Text_Buffers.Unbounded
@b<with> Preelaborate, Nonblocking, Global =@> @b<null is>>
@xcode< @b<type> Buffer_Type @b<is new> Root_Buffer_Type @b<with private>;>
@xcode< @b<function> Get (
Buffer : @b<in out> Buffer_Type) @b<return> String @b<with> Post'Class =@>
Get'Result'First = 1 @b<and then> Current_Indent (Buffer) = 0;>
@xcode< @b<function> Wide_Get (
Buffer : @b<in out> Buffer_Type) @b<return> Wide_String @b<with> Post'Class =@>
Wide_Get'Result'First = 1 @b<and then> Current_Indent (Buffer) = 0;>
@xcode< @b<function> Wide_Wide_Get (
Buffer : @b<in out> Buffer_Type) @b<return> Wide_Wide_String @b<with> Post'Class =@>
Wide_Wide_Get'Result'First = 1
@b<and then> Current_Indent (Buffer) = 0;>
@xcode< @b<function> Get_UTF_8 (
Buffer : @b<in out> Buffer_Type) @b<return> UTF_Encoding.UTF_8_String @b<with> Post'Class =@>
Get_UTF_8'Result'First = 1 @b<and then> Current_Indent (Buffer) = 0;>
@xcode< @b<function> Wide_Get_UTF_16 (
Buffer : @b<in out> Buffer_Type) @b<return> UTF_Encoding.UTF_16_Wide_String @b<with> Post'Class =@>
Wide_Get_UTF_16'Result'First = 1
@b<and then> Current_Indent (Buffer) = 0;>
@xcode<@b<private>
... --@ft<@i< not specified by the language, but will include nonabstract>>
--@ft<@i< overridings of all inherited subprograms that require overriding.>>
@b<end> Ada.Strings.Text_Buffers.Unbounded;>
@xcode<@b<package> Ada.Strings.Text_Buffers.Bounded
@b<with> Pure, Nonblocking, Global =@> @b<null is>>
@xcode< @b<type> Buffer_Type (Max_Characters : Text_Buffer_Count)
@b<is new> Root_Buffer_Type @b<with private> @b<with> Default_Initial_Condition =@> @b<not> Text_Truncated (Buffer_Type);>
@xcode< @b<function> Text_Truncated (Buffer : @b<in> Buffer_Type) @b<return> Boolean;>
@xcode< --@ft<@i< Get, Wide_Get, Wide_Wide_Get, Get_UTF_8, and Wide_Get_UTF_16>>
--@ft<@i< are declared here just as in the Unbounded child.>>>
@xcode<@b<private>
... --@ft<@i< not specified by the language, but will include nonabstract>>
--@ft<@i< overridings of all inherited subprograms that require overriding.>>
@b<end> Ada.Strings.Text_Buffers.Bounded;>
Character_Count returns the number of characters currently stored in a text buffer.
New_Line stores New_Line_Count characters that represent a new line into a text buffer. Current_Indent returns the current indentation associated with the buffer, with zero meaning there is no indentation in effect; Increase_Indent and Decrease_Indent increase or decrease the indentation associated with the buffer.
A call to Put, Wide_Put, Wide_Wide_Put, Put_UTF_8, or Wide_Put_UTF_16 stores a sequence of characters into the text buffer, preceded by Current_Indent(Buffer) spaces (Wide_Wide_Characters with position 32) if there is at least one character in Item and it would have been the first character on the current line.
A call to function Get, Wide_Get, Wide_Wide_Get, Get_UTF_8, or Wide_Get_UTF_16 returns the same sequence of characters as was present in the calls that stored the characters into the buffer, if representable. For a call to Get, if any character in the sequence is not defined in Character, the result is implementation defined. Similarly, for a call to Wide_Get, if any character in the sequence is not defined in Wide_Character, the result is implementation defined. As part of a call on any of the Get functions, the buffer is reset to an empty state, with no stored characters.
In the case of a Buf of type Text_Buffers.Bounded.Buffer_Type, Text_Truncated (Buf) returns True if the various Put procedures together have attempted to store more than Buf.Max_Characters into Buf. If this function returns True, then the various Get functions return a representation of only the first Buf.Max_Characters characters that were stored in Buf.
@s8<@i<Implementation Advice>>
Bounded buffer objects should be implemented without dynamic allocation.
!corrigendum A.5.2(20)
!AI-0144-1
!AI-0302-1
@drepl @xcode< @b<function> Random (Gen : Generator) @b<return> Result_Subtype;> @dby @xcode< @b<function> Random (Gen : Generator) @b<return> Result_Subtype
@b<with> Global =@> @b<overriding in out> Gen;>
@xcode< @b<function> Random (Gen : Generator;
First : Result_Subtype; Last : Result_Subtype) @b<return> Result_Subtype
@b<with> Post =@> Random'Result @b<in> First .. Last,
Global =@> @b<overriding in out> Gen;>
!corrigendum A.5.6(0)
!AI-0208-1
!AI-0302-1
!AI-0366-1
!AI-0407-1
@dinsc
@s8<@i<Static Semantics>>
The library package Numerics.Big_Numbers.Big_Integers has the following declaration:
@xcode<@b<with> Ada.Strings.Text_Buffers; @b<package> Ada.Numerics.Big_Numbers.Big_Integers
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
@xcode< @b<type> Big_Integer @b<is private>
@b<with> Integer_Literal =@> From_Universal_Image,
Put_Image =@> Put_Image;>
@xcode< @b<function> Is_Valid (Arg : Big_Integer) @b<return> Boolean
@b<with> Convention =@> Intrinsic;>
@xcode< @b<subtype> Valid_Big_Integer @b<is> Big_Integer
@b<with> Dynamic_Predicate =@> Is_Valid (Valid_Big_Integer),
Predicate_Failure =@> (@b<raise> Program_Error);>
@xcode< @b<function> "=" (L, R : Valid_Big_Integer) @b<return> Boolean;
@b<function> "<" (L, R : Valid_Big_Integer) @b<return> Boolean; @b<function> "<=" (L, R : Valid_Big_Integer) @b<return> Boolean; @b<function> "@>" (L, R : Valid_Big_Integer) @b<return> Boolean; @b<function> "@>=" (L, R : Valid_Big_Integer) @b<return> Boolean;>
@xcode< @b<function> To_Big_Integer (Arg : Integer) @b<return> Valid_Big_Integer;>
@xcode< @b<subtype> Big_Positive @b<is> Big_Integer
@b<with> Dynamic_Predicate =@> (@b<if> Is_Valid (Big_Positive)
@b<then> Big_Positive @> 0),
Predicate_Failure =@> (@b<raise> Constraint_Error);>
@xcode< @b<subtype> Big_Natural @b<is> Big_Integer
@b<with> Dynamic_Predicate =@> (@b<if> Is_Valid (Big_Natural)
@b<then> Big_Natural @>= 0),
Predicate_Failure =@> (@b<raise> Constraint_Error);>
@xcode< @b<function> In_Range (Arg, Low, High : Valid_Big_Integer) @b<return> Boolean @b<is>
(Low <= Arg @b<and> Arg <= High);>
@xcode< @b<function> To_Integer (Arg : Valid_Big_Integer) @b<return> Integer
@b<with> Pre =@> In_Range (Arg,
Low =@> To_Big_Integer (Integer'First), High =@> To_Big_Integer (Integer'Last))
@b<or else> @b<raise> Constraint_Error;>
@xcode< @b<generic>
@b<type> Int @b<is range> <@>; @b<package> Signed_Conversions @b<is>
@b<function> To_Big_Integer (Arg : Int) @b<return> Valid_Big_Integer; @b<function> From_Big_Integer (Arg : Valid_Big_Integer) @b<return> Int
@b<with> Pre =@> In_Range (Arg, Low =@> To_Big_Integer (Int'First), High =@> To_Big_Integer (Int'Last)) @b<or else> @b<raise> Constraint_Error;
@b<end> Signed_Conversions;>
@xcode< @b<generic>
@b<type> Int @b<is mod> <@>; @b<package> Unsigned_Conversions @b<is>
@b<function> To_Big_Integer (Arg : Int) @b<return> Valid_Big_Integer; @b<function> From_Big_Integer (Arg : Valid_Big_Integer) @b<return> Int
@b<with> Pre =@> In_Range (Arg, Low =@> To_Big_Integer (Int'First), High =@> To_Big_Integer (Int'Last)) @b<or else> @b<raise> Constraint_Error;
@b<end> Unsigned_Conversions;>
@xcode< @b<function> To_String (Arg : Valid_Big_Integer;
Width : Field := 0; Base : Number_Base := 10) @b<return> String
@b<with> Post =@> To_String'Result'First = 1;>
@xcode< @b<function> From_String (Arg : String) @b<return> Valid_Big_Integer;>
@xcode< @b<function> From_Universal_Image (Arg : String) @b<return> Valid_Big_Integer
@b<renames> From_String;>
@xcode< @b<procedure> Put_Image
(Buffer : @b<in out> Ada.Strings.Text_Buffers.Root_Buffer_Type'Class;
Arg : @b<in> Valid_Big_Integer);>
@xcode< @b<function> "+" (L : Valid_Big_Integer) @b<return> Valid_Big_Integer;
@b<function> "-" (L : Valid_Big_Integer) @b<return> Valid_Big_Integer; @b<function> "abs" (L : Valid_Big_Integer) @b<return> Valid_Big_Integer; @b<function> "+" (L, R : Valid_Big_Integer) @b<return> Valid_Big_Integer; @b<function> "-" (L, R : Valid_Big_Integer) @b<return> Valid_Big_Integer; @b<function> "*" (L, R : Valid_Big_Integer) @b<return> Valid_Big_Integer; @b<function> "/" (L, R : Valid_Big_Integer) @b<return> Valid_Big_Integer; @b<function> "mod" (L, R : Valid_Big_Integer) @b<return> Valid_Big_Integer; @b<function> "rem" (L, R : Valid_Big_Integer) @b<return> Valid_Big_Integer; @b<function> "**" (L : Valid_Big_Integer; R : Natural)
@b<return> Valid_Big_Integer;
@b<function> Min (L, R : Valid_Big_Integer) @b<return> Valid_Big_Integer; @b<function> Max (L, R : Valid_Big_Integer) @b<return> Valid_Big_Integer;>
@xcode< @b<function> Greatest_Common_Divisor
(L, R : Valid_Big_Integer) @b<return> Big_Positive @b<with> Pre =@> (L /= 0 @b<and> R /= 0) @b<or else> @b<raise> Constraint_Error;>
@xcode<@b<private>
... -- @ft<@i<not specified by the language>>
@b<end> Ada.Numerics.Big_Numbers.Big_Integers;>
To_String and From_String behave analogously to the Put and Get procedures defined in Text_IO.Integer_IO (in particular, with respect to the interpretation of the Width and Base parameters) except that Constraint_Error, not Data_Error, is propagated in error cases and the result of a call to To_String with a Width parameter of 0 and a nonnegative Arg parameter does not include a leading blank. Put_Image calls To_String (passing in the default values for the Width and Base parameters), prepends a leading blank if the argument is nonnegative, and writes the resulting value to the buffer using Text_Buffers.Put.
The other functions have their usual mathematical meanings.
The type Big_Integer needs finalization (see 7.6).
@s8<@i<Dynamic Semantics>>
for purposes of determining whether predicate checks are performed as part of default initialization, the type Big_Integer is considered to have a subcomponent that has a @fa<default_expression>.
@s8<@i<Implementation Requirements>>
No storage associated with a Big_Integer object shall be lost upon assignment or scope exit.
!corrigendum A.5.7(0)
!AI-0208-1
!AI-0302-1
!AI-0366-1
!AI-0407-1
@dinsc
@s8<@i<Static Semantics>>
The library package Numerics.Big_Numbers.Big_Reals has the following declaration:
@xcode<@b<with> Ada.Numerics.Big_Numbers.Big_Integers;
@b<use all type> Big_Integers.Big_Integer;
@b<with> Ada.Strings.Text_Buffers; @b<package> Ada.Numerics.Big_Numbers.Big_Reals
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
@xcode< @b<type> Big_Real @b<is private>
@b<with> Real_Literal =@> From_Universal_Image,
Put_Image =@> Put_Image;>
@xcode< @b<function> Is_Valid (Arg : Big_Real) @b<return> Boolean
@b<with> Convention =@> Intrinsic;>
@xcode< @b<subtype> Valid_Big_Real @b<is> Big_Real
@b<with> Dynamic_Predicate =@> Is_Valid (Valid_Big_Real),
Predicate_Failure =@> @b<raise> Program_Error;>
@xcode< @b<function> "/" (Num, Den : Big_Integers.Valid_Big_Integer)
@b<return> Valid_Big_Real @b<with> Pre =@> Den /= 0
@b<or else raise> Constraint_Error;>
@xcode< @b<function> Numerator
(Arg : Valid_Big_Real) @b<return> Big_Integers.Valid_Big_Integer @b<with> Post =@> (@b<if> Arg = 0.0 @b<then> Numerator'Result = 0);>
@xcode< @b<function> Denominator (Arg : Valid_Big_Real)
@b<return> Big_Integers.Big_Positive @b<with> Post =@>
(@b<if> Arg = 0.0 @b<then> Denominator'Result = 1
@b<else> Big_Integers.Greatest_Common_Divisor (Numerator (Arg), Denominator'Result) = 1);>
@xcode< @b<function> To_Big_Real (Arg : Big_Integers.Valid_Big_Integer)
@b<return> Valid_Big_Real @b<is> (Arg / 1);>
@xcode< @b<function> To_Real (Arg : Integer) @b<return> Valid_Big_Real @b<is>
(Big_Integers.To_Big_Integer (Arg) / 1);>
@xcode< @b<function> "=" (L, R : Valid_Big_Real) @b<return> Boolean;
@b<function> "<" (L, R : Valid_Big_Real) @b<return> Boolean; @b<function> "<=" (L, R : Valid_Big_Real) @b<return> Boolean; @b<function> "@>" (L, R : Valid_Big_Real) @b<return> Boolean; @b<function> "@>=" (L, R : Valid_Big_Real) @b<return> Boolean;>
@xcode< @b<function> In_Range (Arg, Low, High : Valid_Big_Real) @b<return> Boolean @b<is>
(Low <= Arg @b<and> Arg <= High);>
@xcode< @b<generic>
@b<type> Num @b<is digits> <@>; @b<package> Float_Conversions @b<is>
@b<function> To_Big_Real (Arg : Num) @b<return> Valid_Big_Real; @b<function> From_Big_Real (Arg : Valid_Big_Real) @b<return> Num
@b<with> Pre =@> In_Range (Arg, Low =@> To_Big_Real (Num'First), High =@> To_Big_Real (Num'Last)) @b<or else> (@b<raise> Constraint_Error);
@b<end> Float_Conversions;>
@xcode< @b<generic>
@b<type> Num @b<is delta> <@>; @b<package> Fixed_Conversions @b<is>
@b<function> To_Big_Real (Arg : Num) @b<return> Valid_Big_Real; @b<function> From_Big_Real (Arg : Valid_Big_Real) @b<return> Num
@b<with> Pre =@> In_Range (Arg, Low =@> To_Big_Real (Num'First), High =@> To_Big_Real (Num'Last)) @b<or else> (@b<raise> Constraint_Error);
@b<end> Fixed_Conversions;>
@xcode< @b<function> To_String (Arg : Valid_Big_Real;
Fore : Field := 2; Aft : Field := 3; Exp : Field := 0) @b<return> String
@b<with> Post =@> To_String'Result'First = 1;>
@xcode< @b<function> From_String (Arg : String) @b<return> Valid_Big_Real;>
@xcode< @b<function> From_Universal_Image (Arg : String) @b<return> Valid_Big_Real
@b<renames> From_String;>
@xcode< @b<function> From_Universal_Image (Num, Den : String)
@b<return> Valid_Big_Real @b<is>
(Big_Integers.From_Universal_Image (Num) /
Big_Integers.From_Universal_Image (Den));>
@xcode< @b<function> To_Quotient_String (Arg : Valid_Big_Real) @b<return> String @b<is>
(To_String (Numerator (Arg)) & " / " & To_String (Denominator (Arg))); @b<function> From_Quotient_String (Arg : String) @b<return> Valid_Big_Real;>
@xcode< @b<procedure> Put_Image
(Buffer : @b<in out> Ada.Strings.Text_Buffers.Root_Buffer_Type'Class;
Arg : @b<in> Valid_Big_Real);>
@xcode< @b<function> "+" (L : Valid_Big_Real) @b<return> Valid_Big_Real;
@b<function> "-" (L : Valid_Big_Real) @b<return> Valid_Big_Real; @b<function> "abs" (L : Valid_Big_Real) @b<return> Valid_Big_Real; @b<function> "+" (L, R : Valid_Big_Real) @b<return> Valid_Big_Real; @b<function> "-" (L, R : Valid_Big_Real) @b<return> Valid_Big_Real; @b<function> "*" (L, R : Valid_Big_Real) @b<return> Valid_Big_Real; @b<function> "/" (L, R : Valid_Big_Real) @b<return> Valid_Big_Real; @b<function> "**" (L : Valid_Big_Real; R : Integer)
@b<return> Valid_Big_Real;
@b<function> Min (L, R : Valid_Big_Real) @b<return> Valid_Big_Real; @b<function> Max (L, R : Valid_Big_Real) @b<return> Valid_Big_Real;>
@xcode<@b<private>
... -- @ft<@i<not specified by the language>>
@b<end> Ada.Numerics.Big_Numbers.Big_Reals;>
To_String and From_String behave analogously to the Put and Get procedures defined in Text_IO.Float_IO (in particular, with respect to the interpretation of the Fore, Aft, and Exp parameters), except that Constraint_Error (not Data_Error) is propagated in error cases. From_Quotient_String implements the inverse function of To_Quotient_String; Constraint_Error is propagated in error cases. Put_Image calls To_String, and writes the resulting value to the buffer using Text_Buffers.Put.
For an instance of Float_Conversions or Fixed_Conversions, To_Big_Real is exact (that is, the result represents exactly the same mathematical value as the argument) and From_Big_Real is subject to the same precision rules as a type conversion of a value of type T to the target type Num, where T is a hypothetical floating point type whose model numbers include all of the model numbers of Num as well as the exact mathematical value of the argument.
The other functions have their usual mathematical meanings.
The type Big_Real needs finalization (see 7.6).
@s8<@i<Dynamic Semantics>>
for purposes of determining whether predicate checks are performed as part of default initialization, the type Big_Real is considered to have a subcomponent that has a @fa<default_expression>.
@s8<@i<Implementation Requirements>>
No storage associated with a Big_Real object shall be lost upon assignment or scope exit.
!corrigendum A.10.1(55)
!AI-0241-1
!AI-0302-1
@drepl @xcode< @b<procedure> Put(File : @b<in> File_Type;
Item : @b<in> Num; Width : @b<in> Field := Default_Width; Base : @b<in> Number_Base := Default_Base); @b<procedure> Put(Item : @b<in> Num;
Width : @b<in> Field := Default_Width; Base : @b<in> Number_Base := Default_Base);
@b<procedure> Get(From : @b<in> String;
Item : @b<out> Num; Last : @b<out> Positive);
@b<procedure> Put(To : @b<out> String;
Item : @b<in> Num; Base : @b<in> Number_Base := Default_Base);>
@dby @xcode< @b<procedure> Put(File : @b<in> File_Type;
Item : @b<in> Num; Width : @b<in> Field := Default_Width; Base : @b<in> Number_Base := Default_Base) @b<with> Global =@> @b<overriding in out> File; @b<procedure> Put(Item : @b<in> Num;
Width : @b<in> Field := Default_Width; Base : @b<in> Number_Base := Default_Base)
@b<with> Global =@> @b<in out all>; @b<procedure> Get(From : @b<in> String;
Item : @b<out> Num; Last : @b<out> Positive)
@b<with> Nonblocking; @b<procedure> Put(To : @b<out> String;
Item : @b<in> Num; Base : @b<in> Number_Base := Default_Base)
@b<with> Nonblocking;>
!corrigendum A.10.1(60)
!AI-0241-1
!AI-0302-1
@drepl @xcode< @b<procedure> Put(File : @b<in> File_Type;
Item : @b<in> Num; Width : @b<in> Field := Default_Width; Base : @b<in> Number_Base := Default_Base); @b<procedure> Put(Item : @b<in> Num;
Width : @b<in> Field := Default_Width; Base : @b<in> Number_Base := Default_Base);
@b<procedure> Get(From : @b<in> String;
Item : @b<out> Num; Last : @b<out> Positive);
@b<procedure> Put(To : @b<out> String;
Item : @b<in> Num; Base : @b<in> Number_Base := Default_Base);>
@dby @xcode< @b<procedure> Put(File : @b<in> File_Type;
Item : @b<in> Num; Width : @b<in> Field := Default_Width; Base : @b<in> Number_Base := Default_Base) @b<with> Global =@> @b<overriding in out> File; @b<procedure> Put(Item : @b<in> Num;
Width : @b<in> Field := Default_Width; Base : @b<in> Number_Base := Default_Base)
@b<with> Global =@> @b<in out all>; @b<procedure> Get(From : @b<in> String;
Item : @b<out> Num; Last : @b<out> Positive)
@b<with> Nonblocking; @b<procedure> Put(To : @b<out> String;
Item : @b<in> Num; Base : @b<in> Number_Base := Default_Base)
@b<with> Nonblocking;>
!corrigendum A.15(3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<package> Ada.Command_Line @b<is>
@b<pragma> Preelaborate(Command_Line);>
@dby @xcode<@b<package> Ada.Command_Line
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum A.16(74/2)
!AI-0337-1
!AI-0433-1
@drepl @xindent<Returns the simple name portion of the file name specified by Name. The exception Name_Error is propagated if the string given as Name does not allow the identification of an external file (including directories and special files).> @dby @xindent<Returns the simple name portion of the file name specified by Name. The simple name of a root directory is a name of the root itself. The exception Name_Error is propagated if the string given as Name does not allow the identification of an external file (including directories and special files).>
!corrigendum A.16.1(3/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<package> Ada.Directories.Hierarchical_File_Names @b<is>> @dby @xcode<@b<package> Ada.Directories.Hierarchical_File_Names
@b<with> Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum A.17(3/2)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<package> Ada.Environment_Variables @b<is>
@b<pragma> Preelaborate(Environment_Variables);>
@dby @xcode<@b<package> Ada.Environment_Variables
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum A.18(2/2)
!AI-0111-1
!AI-0196-1
!AI-0416-1
@drepl A variety of sequence and associative containers are provided. Each container includes a @i<cursor> type. A cursor is a reference to an element within a container. Many operations on cursors are common to all of the containers. A cursor referencing an element in a container is considered to be overlapping with the container object itself. @dby A variety of sequence and associative containers are provided. Each container package defines a @i<cursor> type as well as a container type. A cursor is a reference to an element within a container. Many operations on cursors are common to all of the containers. A cursor referencing an element in a container is considered to be overlapping only with the element itself.
!corrigendum A.18(10/2)
!AI-0112-1
!AI-0258-1
@dinsa @xbullet<finalization of the collection of the access type has started if and only if the finalization of the instance has started.>
@dinss @s8<@i<Implementation Requirements>>
For an indefinite container (one whose type is defined in an instance of a child package of Containers whose @fa<defining_identifier> contains "Indefinite"), each element of the container shall be created when it is inserted into the container and finalized when it is deleted from the container (or when the container object is finalized if the element has not been deleted). For a bounded container (one whose type is defined in an instance of a child package of Containers whose @fa<defining_identifier> starts with "Bounded") that is not an indefinite container, all of the elements of the capacity of the container shall be created and default initialized when the container object is created; the elements shall be finalized when the container object is finalized. For other kinds of containers, when elements are created and finalized is unspecified.
For an instance @i<I> of a container package with a container type, the specific type @i<T> of the object returned from a function that returns an object of an iterator interface, as well as the primitive operations of @i<T>, shall be nonblocking. The Global aspect specified for @i<T> and the primitive operations of @i<T> shall be @fc<(@b<in all>, @b<out synchronized>)> or a specification that allows access to fewer global objects.
!corrigendum A.18.2(8/3)
!AI-0111-1
!AI-0112-1
!AI-0212-1
!AI-0339-1
!AI-0399-1
!AI-0400-1
@drepl @xcode< @b<type> Vector @b<is tagged private>
@b<with> Constant_Indexing =@> Constant_Reference,
Variable_Indexing =@> Reference, Default_Iterator =@> Iterate, Iterator_Element =@> Element_Type;
@b<pragma> Preelaborable_Initialization(Vector);>
@dby @xcode< @b<type> Vector @b<is tagged private>
@b<with> Constant_Indexing =@> Constant_Reference,
Variable_Indexing =@> Reference, Default_Iterator =@> Iterate, Iterator_Element =@> Element_Type, Iterator_View =@> Stable.Vector, Aggregate =@> (Empty =@> Empty,
Add_Unnamed =@> Append, New_Indexed =@> New_Vector, Assign_Indexed =@> Replace_Element),
Stable_Properties =@> (Length, Capacity,
Tampering_With_Cursors_Prohibited, Tampering_With_Elements_Prohibited),
Default_Initial_Condition =@>
Length (Vector) = 0 @b<and then> (@b<not> Tampering_With_Cursors_Prohibited (Vector)) @b<and then> (@b<not> Tampering_With_Elements_Prohibited (Vector)),
Preelaborable_Initialization;>
!corrigendum A.18.2(12/2)
!AI-0112-1
!AI-0339-1
@dinsa @xcode< @b<function> "=" (Left, Right : Vector) @b<return> Boolean;> @dinss @xcode< @b<function> Tampering_With_Cursors_Prohibited
(Container : Vector) @b<return> Boolean @b<with> Nonblocking, Global =@> @b<null>, Use_Formal =@> @b<null>;>
@xcode< @b<function> Tampering_With_Elements_Prohibited
(Container : Vector) @b<return> Boolean @b<with> Nonblocking, Global =@> @b<null>, Use_Formal =@> @b<null>;>
@xcode< @b<function> Maximum_Length @b<return> Count_Type
@b<with> Nonblocking, Global =@> @b<null>, Use_Formal =@> @b<null>;>
@xcode< @b<function> Empty (Capacity : Count_Type := @ft<@i<implementation-defined>>)
@b<return> Vector @b<with> Pre =@> Capacity <= Maximum_Length
@b<or else raise> Constraint_Error,
Post =@>
Capacity (Empty'Result) @>= Capacity @b<and then> @b<not> Tampering_With_Elements_Prohibited (Empty'Result) @b<and then> @b<not> Tampering_With_Cursors_Prohibited (Empty'Result) @b<and then> Length (Empty'Result) = 0;>
!corrigendum A.18.2(14/2)
!AI-0112-1
!AI-0212-1
@drepl @xcode< @b<function> To_Vector
(New_Item : Element_Type;
Length : Count_Type) @b<return> Vector>
@dby @xcode< @b<function> To_Vector
(New_Item : Element_Type;
Length : Count_Type) @b<return> Vector @b<with> Pre =@> Length <= Maximum_Length @b<or else raise> Constraint_Error, Post =@> To_Vector'Result.Length = Length @b<and then> @b<not> Tampering_With_Elements_Prohibited (To_Vector'Result) @b<and then> @b<not> Tampering_With_Cursors_Prohibited (To_Vector'Result) @b<and then> To_Vector'Result.Capacity @>= Length;>
@xcode< @b<function> New_Vector (First, Last : Index_Type) @b<return> Vector @b<is>
(To_Vector (Count_Type (Last - First + 1))) @b<with> Pre =@> First = Index_Type'First;>
!corrigendum A.18.2(47/2)
!AI-0112-1
!AI-0212-1
!AI-0400-1
@drepl @xcode< @b<procedure> Append (Container : @b<in out> Vector;
New_Item : @b<in> Element_Type; Count : @b<in> Count_Type := 1);>
@dby @xcode< @b<procedure> Append (Container : @b<in out> Vector;
New_Item : @b<in> Element_Type; Count : @b<in> Count_Type) @b<with> Pre =@> (@b<not> Tampering_With_Cursors_Prohibited (Container)
@b<or else raise> Program_Error) @b<and then>
(Length (Container) <= Maximum_Length - Count
@b<or else raise> Constraint_Error),
Post =@>
Length (Container)'Old + Count = Length (Container) @b<and then> Capacity (Container) @>= Length (Container);>
@xcode< @b<procedure> Append (Container : @b<in out> Vector;
New_Item : @b<in> Element_Type) @b<with> Pre =@> (@b<not> Tampering_With_Cursors_Prohibited (Container)
@b<or else raise> Program_Error) @b<and then>
(Length (Container) <= Maximum_Length - 1
@b<or else raise> Constraint_Error),
Post =@> Length (Container)'Old + 1 = Length (Container) @b<and then>
Capacity (Container) @>= Length (Container);>
!corrigendum A.18.2(74.1/3)
!AI-0112-1
!AI-0266-1
@drepl @xcode< @b<function> Iterate (Container : @b<in> Vector)
@b<return> Vector_Iterator_Interfaces.Reversible_Iterator'Class;>
@dby @xcode< @b<function> Iterate (Container : @b<in> Vector)
@b<return> Vector_Iterator_Interfaces.Parallel_Reversible_Iterator'Class @b<with> Post =@> Tampering_With_Cursors_Prohibited (Container);>
!corrigendum A.18.2(98/3)
!AI-0112-1
!AI-0339-1
@dinsa @xindent<If Left and Right denote the same vector object, then the function returns True. If Left and Right have different lengths, then the function returns False. Otherwise, it compares each element in Left to the corresponding element in Right using the generic formal equality operator. If any such comparison returns False, the function returns False; otherwise, it returns True. Any exception raised during evaluation of element equality is propagated.> @dinss @xcode<@b<function> Tampering_With_Cursors_Prohibited
(Container : Vector) @b<return> Boolean @b<with> Nonblocking, Global =@> @b<null>, Use_Formal =@> @b<null>;>
@xindent<Returns True if tampering with cursors or tampering with elements is currently prohibited for Container, and returns False otherwise.>
@xcode<@b<function> Tampering_With_Elements_Prohibited
(Container : Vector) @b<return> Boolean @b<with> Nonblocking, Global =@> @b<null>, Use_Formal =@> @b<null>;>
@xindent<Always returns False, regardless of whether tampering with elements is prohibited.>
@xcode<@b<function> Maximum_Length @b<return> Count_Type
@b<with> Nonblocking, Global =@> @b<null>, Use_Formal =@> @b<null>;>
@xindent<Returns the maximum Length of a Vector, based on the index type.>
@xcode<@b<function> Empty (Capacity : Count_Type := @ft<@i<implementation-defined>>)
@b<return> Vector @b<with> Pre =@> Capacity <= Maximum_Length
@b<or else raise> Constraint_Error,
Post =@>
Capacity (Empty'Result) @>= Capacity @b<and then> @b<not> Tampering_With_Elements_Prohibited (Empty'Result) @b<and then> @b<not> Tampering_With_Cursors_Prohibited (Empty'Result) @b<and then> Length (Empty'Result) = 0;>
@xindent<Returns an empty vector.>
!corrigendum A.18.2(125/2)
!AI-0112-1
!AI-0196-1
@drepl @xindent<If Index is not in the range First_Index (Container) .. Last_Index (Container), then No_Element is returned. Otherwise, a cursor designating the element at position Index in Container is returned.> @dby @xindent<Returns a cursor designating the element at position Index in Container; returns No_Element if Index does not designate an element. For the purposes of determining whether the parameters overlap in a call to To_Cursor, the Container parameter is not considered to overlap with any object (including itself).>
!corrigendum A.18.2(133/3)
!AI-0112-1
!AI-0196-1
@drepl @xindent<If Index is not in the range First_Index (Container) .. Last_Index (Container), then Constraint_Error is propagated. Otherwise, Replace_Element assigns the value New_Item to the element at position Index. Any exception raised during the assignment is propagated. The element at position Index is not an empty element after successful call to Replace_Element.>
@dby @xindent<Replace_Element assigns the value New_Item to the element at position Index. Any exception raised during the assignment is propagated. The element at position Index is not an empty element after successful call to Replace_Element. For the purposes of determining whether the parameters overlap in a call to Replace_Element, the Container parameter is not considered to overlap with any object (including itself), and the Index parameter is considered to overlap with the element at position Index.>
!corrigendum A.18.2(135/3)
!AI-0112-1
!AI-0196-1
@drepl @xindent<If Position equals No_Element, then Constraint_Error is propagated; if Position does not designate an element in Container, then Program_Error is propagated. Otherwise, Replace_Element assigns New_Item to the element designated by Position. Any exception raised during the assignment is propagated. The element at Position is not an empty element after successful call to Replace_Element.> @dby @xindent<Replace_Element assigns New_Item to the element designated by Position. Any exception raised during the assignment is propagated. The element at Position is not an empty element after successful call to Replace_Element. For the purposes of determining whether the parameters overlap in a call to Replace_Element, the Container parameter is not considered to overlap with any object (including itself).>
!corrigendum A.18.2(175/2)
!AI-0112-1
!AI-0212-1
!AI-0400-1
@dinsa @xindent<Equivalent to Insert (Container, Last_Index (Container) + 1, New_Item, Count).> @dinss @xcode<@b<procedure> Append (Container : @b<in out> Vector;
New_Item : @b<in> Element_Type) @b<with> Pre =@> (@b<not> Tampering_With_Cursors_Prohibited (Container)
@b<or else raise> Program_Error) @b<and then>
(Length (Container) <= Maximum_Length - 1
@b<or else raise> Constraint_Error),
Post =@> Length (Container)'Old + 1 = Length (Container) @b<and then>
Capacity (Container) @>= Length (Container);>
@xindent<Equivalent to Insert (Container, Last_Index (Container) + 1, New_Item, 1).>
!corrigendum A.18.2(230.1/3)
!AI-0112-1
!AI-0266-1
@drepl @xcode<@b<function> Iterate (Container : @b<in> Vector)
@b<return> Vector_Iterator_Interfaces.Reversible_Iterator'Class;>
@dby @xcode<@b<function> Iterate (Container : @b<in> Vector)
@b<return> Vector_Iterator_Interfaces.Parallel_Reversible_Iterator'Class @b<with> Post =@> Tampering_With_Cursors_Prohibited (Container);>
!corrigendum A.18.3(6/3)
!AI-0111-1
!AI-0112-1
!AI-0212-1
!AI-0339-1
!AI-0391-1
!AI-0399-1
!AI-0400-1
@drepl @xcode< @b<type> List @b<is tagged private>
@b<with> Constant_Indexing =@> Constant_Reference,
Variable_Indexing =@> Reference, Default_Iterator =@> Iterate, Iterator_Element =@> Element_Type;
@b<pragma> Preelaborable_Initialization(List);>
@dby @xcode< @b<type> List @b<is tagged private>
@b<with> Constant_Indexing =@> Constant_Reference,
Variable_Indexing =@> Reference, Default_Iterator =@> Iterate, Iterator_Element =@> Element_Type, Iterator_View =@> Stable.List, Aggregate =@> (Empty =@> Empty,
Add_Unnamed =@> Append),
Stable_Properties =@> (Length,
Tampering_With_Cursors_Prohibited, Tampering_With_Elements_Prohibited),
Default_Initial_Condition =@>
Length (List) = 0 @b<and then> (@b<not> Tampering_With_Cursors_Prohibited (List)) @b<and then> (@b<not> Tampering_With_Elements_Prohibited (List)),
Preelaborable_Initialization;>
!corrigendum A.18.3(10/2)
!AI-0112-1
!AI-0339-1
@dinsa @xcode< @b<function> "=" (Left, Right : List) @b<return> Boolean;> @dinss @xcode< @b<function> Tampering_With_Cursors_Prohibited
(Container : List) @b<return> Boolean @b<with> Nonblocking, Global =@> @b<null>, Use_Formal =@> @b<null>;>
@xcode< @b<function> Tampering_With_Elements_Prohibited
(Container : List) @b<return> Boolean @b<with> Nonblocking, Global =@> @b<null>, Use_Formal =@> @b<null>;>
@xcode< @b<function> Empty @b<return> List
@b<is> (Empty_List) @b<with> Post =@>
@b<not> Tampering_With_Elements_Prohibited (Empty'Result) @b<and then> @b<not> Tampering_With_Cursors_Prohibited (Empty'Result) @b<and then> Length (Empty'Result) = 0;>
!corrigendum A.18.3(23/2)
!AI-0112-1
!AI-0391-1
!AI-0400-1
@drepl @xcode< @b<procedure> Append (Container : @b<in out> List;
New_Item : @b<in> Element_Type; Count : @b<in> Count_Type := 1);>
@dby @xcode< @b<procedure> Append (Container : @b<in out> List;
New_Item : @b<in> Element_Type; Count : @b<in> Count_Type) @b<with> Pre =@> (@b<not> Tampering_With_Cursors_Prohibited (Container)
@b<or else raise> Program_Error) @b<and then>
(Length (Container) <= Count_Type'Last - Count
@b<or else raise> Constraint_Error),
Post =@> Length (Container)'Old + Count = Length (Container);>
@xcode< @b<procedure> Append (Container : @b<in out> List;
New_Item : @b<in> Element_Type) @b<with> Pre =@> (@b<not> Tampering_With_Cursors_Prohibited (Container)
@b<or else raise> Program_Error) @b<and then>
(Length (Container) <= Count_Type'Last - 1
@b<or else raise> Constraint_Error),
Post =@> Length (Container)'Old + 1 = Length (Container);>
!corrigendum A.18.3(46.1/3)
!AI-0112-1
!AI-0266-1
@drepl @xcode< @b<function> Iterate (Container : @b<in> List)
@b<return> List_Iterator_Interfaces.Reversible_Iterator'Class;>
@dby @xcode< @b<function> Iterate (Container : @b<in> List)
@b<return> List_Iterator_Interfaces.Parallel_Reversible_Iterator'Class @b<with> Post =@> Tampering_With_Cursors_Prohibited (Container);>
!corrigendum A.18.3(81/3)
!AI-0112-1
!AI-0196-1
@drepl @xindent<If Position equals No_Element, then Constraint_Error is propagated; if Position does not designate an element in Container, then Program_Error is propagated. Otherwise, Replace_Element assigns the value New_Item to the element designated by Position.> @dby @xindent<Replace_Element assigns the value New_Item to the element designated by Position. For the purposes of determining whether the parameters overlap in a call to Replace_Element, the Container parameter is not considered to overlap with any object (including itself).>
!corrigendum A.18.3(144.1/3)
!AI-0112-1
!AI-0266-1
@drepl @xcode<@b<function> Iterate (Container : @b<in> List)
@b<return> List_Iterator_Interfaces.Reversible_Iterator'Class;>
@dby @xcode<@b<function> Iterate (Container : @b<in> List)
@b<return> List_Iterator_Interfaces.Parallel_Reversible_Iterator'Class @b<with> Post =@> Tampering_With_Cursors_Prohibited (Container);>
!corrigendum A.18.4(36/3)
!AI-0112-1
!AI-0196-1
@drepl @xindent<If Position equals No_Element, then Constraint_Error is propagated; if Position does not designate an element in Container, then Program_Error is propagated. Otherwise, Replace_Element assigns New_Item to the element of the node designated by Position.> @dby @xindent<Replace_Element assigns New_Item to the element of the node designated by Position. For the purposes of determining whether the parameters overlap in a call to Replace_Element, the Container parameter is not considered to overlap with any object (including itself).>
!corrigendum A.18.5(3/2)
!AI-0111-1
!AI-0112-1
!AI-0212-1
!AI-0339-1
!AI-0399-1
@drepl @xcode< @b<type> Map @b<is tagged private>
@b<with> Constant_Indexing =@> Constant_Reference,
Variable_Indexing =@> Reference, Default_Iterator =@> Iterate, Iterator_Element =@> Element_Type;
@b<pragma> Preelaborable_Initialization(Map);>
@dby @xcode< @b<type> Map @b<is tagged private>
@b<with> Constant_Indexing =@> Constant_Reference,
Variable_Indexing =@> Reference, Default_Iterator =@> Iterate, Iterator_Element =@> Element_Type, Iterator_View =@> Stable.Map, Aggregate =@> (Empty =@> Empty,
Add_Named =@> Insert),
Stable_Properties =@> (Length,
Tampering_With_Cursors_Prohibited, Tampering_With_Elements_Prohibited),
Default_Initial_Condition =@>
Length (Map) = 0 @b<and then> (@b<not> Tampering_With_Cursors_Prohibited (Map)) @b<and then> (@b<not> Tampering_With_Elements_Prohibited (Map)),
Preelaborable_Initialization;>
!corrigendum A.18.5(7/2)
!AI-0112-1
!AI-0339-1
@dinsa @xcode< @b<function> "=" (Left, Right : Map) @b<return> Boolean;> @dinss @xcode< @b<function> Tampering_With_Cursors_Prohibited
(Container : Map) @b<return> Boolean @b<with> Nonblocking, Global =@> @b<null>, Use_Formal =@> @b<null>;>
@xcode< @b<function> Tampering_With_Elements_Prohibited
(Container : Map) @b<return> Boolean @b<with> Nonblocking, Global =@> @b<null>, Use_Formal =@> @b<null>;>
@xcode< @b<function> Empty (Capacity : Count_Type := @ft<@i<implementation-defined>>)
@b<return> Map @b<with> Post =@>
Capacity (Empty'Result) @>= Capacity @b<and then> @b<not> Tampering_With_Elements_Prohibited (Empty'Result) @b<and then> @b<not> Tampering_With_Cursors_Prohibited (Empty'Result) @b<and then> Length (Empty'Result) = 0;>
!corrigendum A.18.5(37.1/3)
!AI-0112-1
!AI-0266-1
@drepl @xcode< @b<function> Iterate (Container : @b<in> Map)
@b<return> Map_Iterator_Interfaces.Forward_Iterator'Class;>
@dby @xcode< @b<function> Iterate (Container : @b<in> Map)
@b<return> Map_Iterator_Interfaces.Parallel_Iterator'Class @b<with> Post =@> Tampering_With_Cursors_Prohibited (Container);>
!corrigendum A.18.5(61.1/3)
!AI-0112-1
!AI-0266-1
@drepl @xcode<@b<function> Iterate (Container : @b<in> Map)
@b<return> Map_Iterator_Interfaces.Forward_Iterator'Class;>
@dby @xcode<@b<function> Iterate (Container : @b<in> Map)
@b<return> Map_Iterator_Interfaces.Parallel_Iterator'Class @b<with> Post =@> Tampering_With_Cursors_Prohibited (Container);>
!corrigendum A.18.6(4/3)
!AI-0111-1
!AI-0112-1
!AI-0212-1
!AI-0339-1
!AI-0399-1
@drepl @xcode< @b<type> Map @b<is tagged private>
@b<with> Constant_Indexing =@> Constant_Reference,
Variable_Indexing =@> Reference, Default_Iterator =@> Iterate, Iterator_Element =@> Element_Type;
@b<pragma> Preelaborable_Initialization(Map);>
@dby @xcode< @b<type> Map @b<is tagged private>
@b<with> Constant_Indexing =@> Constant_Reference,
Variable_Indexing =@> Reference, Default_Iterator =@> Iterate, Iterator_Element =@> Element_Type, Iterator_View =@> Stable.Map, Aggregate =@> (Empty =@> Empty,
Add_Named =@> Insert),
Stable_Properties =@> (Length,
Tampering_With_Cursors_Prohibited, Tampering_With_Elements_Prohibited),
Default_Initial_Condition =@>
Length (Map) = 0 @b<and then> (@b<not> Tampering_With_Cursors_Prohibited (Map)) @b<and then> (@b<not> Tampering_With_Elements_Prohibited (Map)),
Preelaborable_Initialization;>
!corrigendum A.18.6(7/2)
!AI-0112-1
!AI-0339-1
@dinsa @xcode< @b<function> "=" (Left, Right : Map) @b<return> Boolean;> @dinss @xcode< @b<function> Tampering_With_Cursors_Prohibited
(Container : Map) @b<return> Boolean @b<with> Nonblocking, Global =@> @b<null>, Use_Formal =@> @b<null>;>
@xcode< @b<function> Tampering_With_Elements_Prohibited
(Container : Map) @b<return> Boolean @b<with> Nonblocking, Global =@> @b<null>, Use_Formal =@> @b<null>;>
@xcode< @b<function> Empty @b<return> Map
@b<is> (Empty_Map) @b<with> Post =@>
@b<not> Tampering_With_Elements_Prohibited (Empty'Result) @b<and then> @b<not> Tampering_With_Cursors_Prohibited (Empty'Result) @b<and then> Length (Empty'Result) = 0;>
!corrigendum A.18.6(51.1/3)
!AI-0112-1
!AI-0266-1
@drepl @xcode< @b<function> Iterate (Container : @b<in> Map)
@b<return> Map_Iterator_Interfaces.Reversible_Iterator'Class;>
@dby @xcode< @b<function> Iterate (Container : @b<in> Map)
@b<return> Map_Iterator_Interfaces.Parallel_Reversible_Iterator'Class @b<with> Post =@> Tampering_With_Cursors_Prohibited (Container);>
!corrigendum A.18.6(94.1/3)
!AI-0112-1
!AI-0266-1
@drepl @xcode<@b<function> Iterate (Container : @b<in> Map)
@b<return> Map_Iterator_Interfaces.Reversible_Iterator'Class;>
@dby @xcode<@b<function> Iterate (Container : @b<in> Map)
@b<return> Map_Iterator_Interfaces.Parallel_Reversible_Iterator'Class @b<with> Post =@> Tampering_With_Cursors_Prohibited (Container);>
!corrigendum A.18.7(34/2)
!AI-0112-1
!AI-0196-1
@drepl @xindent<If Position equals No_Element, then Constraint_Error is propagated; if Position does not designate an element in Container, then Program_Error is propagated. If an element equivalent to New_Item is already present in Container at a position other than Position, Program_Error is propagated. Otherwise, Replace_Element assigns New_Item to the element designated by Position. Any exception raised by the assignment is propagated.> @dby @xindent<Replace_Element assigns New_Item to the element designated by Position. Any exception raised by the assignment is propagated. For the purposes of determining whether the parameters overlap in a call to Replace_Element, the Container parameter is not considered to overlap with any object (including itself).>
!corrigendum A.18.8(3/3)
!AI-0111-1
!AI-0112-1
!AI-0212-1
!AI-0339-1
!AI-0399-1
@drepl @xcode< @b<type> Set @b<is tagged private>
@b<with> Constant_Indexing =@> Constant_Reference,
Default_Iterator =@> Iterate, Iterator_Element =@> Element_Type;
@b<pragma> Preelaborable_Initialization(Set);>
@dby @xcode< @b<type> Set @b<is tagged private>
@b<with> Constant_Indexing =@> Constant_Reference,
Default_Iterator =@> Iterate, Iterator_Element =@> Element_Type, Iterator_View =@> Stable.Set, Aggregate =@> (Empty =@> Empty,
Add_Unnamed =@> Include),
Stable_Properties =@> (Length,
Tampering_With_Cursors_Prohibited),
Default_Initial_Condition =@>
Length (Set) = 0 @b<and then> (@b<not> Tampering_With_Cursors_Prohibited (Set)),
Preelaborable_Initialization;>
!corrigendum A.18.8(8/2)
!AI-0112-1
!AI-0339-1
@dinsa @xcode< @b<function> Equivalent_Sets (Left, Right : Set) @b<return> Boolean;> @dinss @xcode< @b<function> Tampering_With_Cursors_Prohibited
(Container : Set) @b<return> Boolean @b<with> Nonblocking, Global =@> @b<null>, Use_Formal =@> @b<null>;>
@xcode< @b<function> Empty (Capacity : Count_Type := @ft<@i<implementation-defined>>)
@b<return> Set @b<with> Post =@>
Capacity (Empty'Result) @>= Capacity @b<and then> @b<not> Tampering_With_Cursors_Prohibited (Empty'Result) @b<and then> Length (Empty'Result) = 0;>
!corrigendum A.18.8(49.1/3)
!AI-0112-1
!AI-0266-1
@drepl @xcode< @b<function> Iterate (Container : @b<in> Set)
@b<return> Set_Iterator_Interfaces.Forward_Iterator'Class;>
@dby @xcode< @b<function> Iterate (Container : @b<in> Set)
@b<return> Set_Iterator_Interfaces.Parallel_Iterator'Class @b<with> Post =@> Tampering_With_Cursors_Prohibited (Container);>
!corrigendum A.18.8(85.1/3)
!AI-0112-1
!AI-0266-1
@drepl @xcode<@b<function> Iterate (Container : @b<in> Set)
@b<return> Set_Iterator_Interfaces.Forward_Iterator'Class;>
@dby @xcode<@b<function> Iterate (Container : @b<in> Set)
@b<return> Set_Iterator_Interfaces.Parallel_Iterator'Class @b<with> Post =@> Tampering_With_Cursors_Prohibited (Container);>
!corrigendum A.18.9(4/3)
!AI-0111-1
!AI-0112-1
!AI-0212-1
!AI-0339-1
!AI-0399-1
@drepl @xcode< @b<type> Set @b<is tagged private>
@b<with> Constant_Indexing =@> Constant_Reference,
Default_Iterator =@> Iterate, Iterator_Element =@> Element_Type;
@b<pragma> Preelaborable_Initialization(Set);>
@dby @xcode< @b<type> Set @b<is tagged private>
@b<with> Constant_Indexing =@> Constant_Reference,
Default_Iterator =@> Iterate, Iterator_Element =@> Element_Type, Iterator_View =@> Stable.Set, Aggregate =@> (Empty =@> Empty,
Add_Unnamed =@> Include),
Stable_Properties =@> (Length,
Tampering_With_Cursors_Prohibited),
Default_Initial_Condition =@>
Length (Set) = 0 @b<and then> (@b<not> Tampering_With_Cursors_Prohibited (Set)),
Preelaborable_Initialization;>
!corrigendum A.18.9(9/2)
!AI-0112-1
!AI-0339-1
@dinsa @xcode< @b<function> Equivalent_Sets (Left, Right : Set) @b<return> Boolean;> @dinss @xcode< @b<function> Tampering_With_Cursors_Prohibited
(Container : Set) @b<return> Boolean @b<with> Nonblocking, Global =@> @b<null>, Use_Formal =@> @b<null>;>
@xcode< @b<function> Empty @b<return> Set
@b<is> (Empty_Set) @b<with> Post =@>
@b<not> Tampering_With_Cursors_Prohibited (Empty'Result) @b<and then> Length (Empty'Result) = 0;>
!corrigendum A.18.9(61.1/3)
!AI-0112-1
!AI-0266-1
@drepl @xcode< @b<function> Iterate (Container : @b<in> Set)
@b<return> Set_Iterator_Interfaces.Reversible_Iterator'Class;>
@dby @xcode< @b<function> Iterate (Container : @b<in> Set)
@b<return> Set_Iterator_Interfaces.Parallel_Reversible_Iterator'Class @b<with> Post =@> Tampering_With_Cursors_Prohibited (Container);>
!corrigendum A.18.9(113.1/3)
!AI-0112-1
!AI-0266-1
@drepl @xcode<@b<function> Iterate (Container : @b<in> Set)
@b<return> Set_Iterator_Interfaces.Reversible_Iterator'Class;>
@dby @xcode<@b<function> Iterate (Container : @b<in> Set)
@b<return> Set_Iterator_Interfaces.Parallel_Reversible_Iterator'Class @b<with> Post =@> Tampering_With_Cursors_Prohibited (Container);>
!corrigendum A.18.10(8/3)
!AI-0111-1
!AI-0112-1
!AI-0399-1
@drepl @xcode< @b<type> Tree @b<is tagged private>
@b<with> Constant_Indexing =@> Constant_Reference,
Variable_Indexing =@> Reference, Default_Iterator =@> Iterate, Iterator_Element =@> Element_Type;
@b<pragma> Preelaborable_Initialization(Tree);>
@dby @xcode< @b<type> Tree @b<is tagged private>
@b<with> Constant_Indexing =@> Constant_Reference,
Variable_Indexing =@> Reference, Default_Iterator =@> Iterate, Iterator_Element =@> Element_Type, Iterator_View =@> Stable.Tree, Stable_Properties =@> (Node_Count,
Tampering_With_Cursors_Prohibited, Tampering_With_Elements_Prohibited),
Default_Initial_Condition =@>
Node_Count (Tree) = 1 @b<and then> (@b<not> Tampering_With_Cursors_Prohibited (Tree)) @b<and then> (@b<not> Tampering_With_Elements_Prohibited (Tree)),
Preelaborable_Initialization;>
!corrigendum A.18.10(15/3)
!AI-0112-1
!AI-0339-1
@dinsa @xcode< @b<function> "=" (Left, Right : Tree) @b<return> Boolean;> @dinss @xcode< @b<function> Tampering_With_Cursors_Prohibited
(Container : Tree) @b<return> Boolean @b<with> Nonblocking, Global =@> @b<null>, Use_Formal =@> @b<null>;>
@xcode< @b<function> Tampering_With_Elements_Prohibited
(Container : Tree) @b<return> Boolean @b<with> Nonblocking, Global =@> @b<null>, Use_Formal =@> @b<null>;>
@xcode< @b<function> Empty @b<return> Tree
@b<is> (Empty_Tree) @b<with> Post =@>
@b<not> Tampering_With_Elements_Prohibited (Empty'Result) @b<and then> @b<not> Tampering_With_Cursors_Prohibited (Empty'Result) @b<and then> Node_Count (Empty'Result) = 1;>
!corrigendum A.18.10(44/3)
!AI-0112-1
!AI-0266-1
@drepl @xcode< @b<function> Iterate (Container : @b<in> Tree)
@b<return> Tree_Iterator_Interfaces.Forward_Iterator'Class;>
@dby @xcode< @b<function> Iterate (Container : @b<in> Tree)
@b<return> Tree_Iterator_Interfaces.Parallel_Iterator'Class @b<with> Post =@> Tampering_With_Cursors_Prohibited (Container);>
!corrigendum A.18.10(45/3)
!AI-0112-1
!AI-0266-1
@drepl @xcode< @b<function> Iterate_Subtree (Position : @b<in> Cursor)
@b<return> Tree_Iterator_Interfaces.Forward_Iterator'Class;>
@dby @xcode< @b<function> Iterate_Subtree (Position : @b<in> Cursor)
@b<return> Tree_Iterator_Interfaces.Parallel_Iterator'Class @b<with> Pre =@> Position /= No_Element @b<or else raise> Constraint_Error,
Global =@> @b<in all>;>
@xcode< @b<function> Iterate_Subtree (Container : @b<in> Tree; Position : @b<in> Cursor)
@b<return> Tree_Iterator_Interfaces.Parallel_Iterator'Class @b<with> Pre =@> (Position /= No_Element
@b<or else raise> Constraint_Error) @b<and then>
(Meaningful_For (Container, Position)
@b<or else raise> Program_Error),
Post =@> Tampering_With_Cursors_Prohibited (Container);>
!corrigendum A.18.10(70/3)
!AI-0112-1
!AI-0266-1
@drepl @xcode< @b<function> Iterate_Children (Container : @b<in> Tree; Parent : @b<in> Cursor)
@b<return> Tree_Iterator_Interfaces.Reversible_Iterator'Class;>
@dby @xcode< @b<function> Iterate_Children (Container : @b<in> Tree; Parent : @b<in> Cursor)
@b<return> Tree_Iterator_Interfaces.Parallel_Reversible_Iterator'Class @b<with> Pre =@> (Parent /= No_Element
@b<or else raise> Constraint_Error) @b<and then>
(Meaningful_For (Container, Parent)
@b<or else raise> Program_Error),
Post =@> Tampering_With_Cursors_Prohibited (Container);>
!corrigendum A.18.10(116/3)
!AI-0112-1
!AI-0266-1
@drepl @xindent<If Position equals No_Element, then Constraint_Error is propagated; if Position does not designate an element in Container (including if it designates the root node), then Program_Error is propagated. Otherwise, Replace_Element assigns the value New_Item to the element designated by Position.> @dby @xindent<Replace_Element assigns the value New_Item to the element designated by Position. For the purposes of determining whether the parameters overlap in a call to Replace_Element, the Container parameter is not considered to overlap with any object (including itself).>
!corrigendum A.18.10(156/3)
!AI-0112-1
!AI-0266-1
@drepl @xcode<@b<function> Iterate (Container : @b<in> Tree)
@b<return> Tree_Iterator_Interfaces.Forward_Iterator'Class;>
@dby @xcode<@b<function> Iterate (Container : @b<in> Tree)
@b<return> Tree_Iterator_Interfaces.Parallel_Iterator'Class @b<with> Post =@> Tampering_With_Cursors_Prohibited (Container);>
!corrigendum A.18.10(158/3)
!AI-0112-1
!AI-0266-1
@drepl @xcode<@b<function> Iterate_Subtree (Position : @b<in> Cursor)
@b<return> Tree_Iterator_Interfaces.Forward_Iterator'Class;>
@dby @xcode<@b<function> Iterate_Subtree (Position : @b<in> Cursor)
@b<return> Tree_Iterator_Interfaces.Parallel_Iterator'Class @b<with> Pre =@> Position /= No_Element @b<or else raise> Constraint_Error,
Global =@> @b<in all>;>
!corrigendum A.18.10(159/3)
!AI-0112-1
!AI-0266-1
@drepl @xindent<If Position equals No_Element, then Constraint_Error is propagated. Otherwise, Iterate_Subtree returns an iterator object (see 5.5.1) that will generate a value for a loop parameter (see 5.5.2) designating each element in the subtree rooted by the node designated by Position, starting from the node designated by Position and proceeding in a depth-first order. If Position equals No_Element, then Constraint_Error is propagated. Tampering with the cursors of the container that contains the node designated by Position is prohibited while the iterator object exists (in particular, in the @fa<sequence_of_statements> of the @fa<loop_statement> whose @fa<iterator_specification> denotes this object). The iterator object needs finalization.> @dby @xindent<Iterate_Subtree returns an iterator object (see 5.5.1) that will generate a value for a loop parameter (see 5.5.2) designating each element in the subtree rooted by the node designated by Position, starting from the node designated by Position and proceeding in a depth-first order when used as a forward iterator, and processing all nodes in the subtree concurrently when used as a parallel iterator. Tampering with the cursors of the container that contains the node designated by Position is prohibited while the iterator object exists (in particular, in the @fa<sequence_of_statements> of the @fa<loop_statement> whose @fa<iterator_specification> denotes this object). The iterator object needs finalization.>
@xcode<@b<function> Iterate_Subtree (Container : @b<in> Tree; Position : @b<in> Cursor)
@b<return> Tree_Iterator_Interfaces.Parallel_Iterator'Class @b<with> Pre =@> (Position /= No_Element
@b<or else raise> Constraint_Error) @b<and then>
(Meaningful_For (Container, Position)
@b<or else raise> Program_Error),
Post =@> Tampering_With_Cursors_Prohibited (Container);>
@xindent<Iterate_Subtree returns an iterator object (see 5.5.1) that will generate a value for a loop parameter (see 5.5.2) designating each element in the subtree rooted by the node designated by Position in Container, starting from the node designated by Position and proceeding in a depth-first order when used as a forward iterator, and processing all nodes in the subtree concurrently when used as a parallel iterator. Tampering with the cursors of the container that contains the node designated by Position is prohibited while the iterator object exists (in particular, in the @fa<sequence_of_statements> of the @fa<loop_statement> whose @fa<iterator_specification> denotes this object). The iterator object needs finalization.>
!corrigendum A.18.10(218/3)
!AI-0112-1
!AI-0266-1
@drepl @xcode<@b<function> Iterate_Children (Container : @b<in> Tree; Parent : @b<in> Cursor)
@b<return> Tree_Iterator_Interfaces.Reversible_Iterator'Class;>
@dby @xcode<@b<function> Iterate_Children (Container : @b<in> Tree; Parent : @b<in> Cursor)
@b<return> Tree_Iterator_Interfaces.Parallel_Reversible_Iterator'Class @b<with> Pre =@> (Parent /= No_Element
@b<or else raise> Constraint_Error) @b<and then>
(Meaningful_For (Container, Parent)
@b<or else raise> Program_Error),
Post =@> Tampering_With_Cursors_Prohibited (Container);>
!corrigendum A.18.10(219/3)
!AI-0112-1
!AI-0266-1
@drepl @xindent<Iterate_Children returns a reversible iterator object (see 5.5.1) that will generate a value for a loop parameter (see 5.5.2) designating each child node of Parent. If Parent equals No_Element, then Constraint_Error is propagated. If Parent does not designate a node in Container, then Program_Error is propagated. Otherwise, when used as a forward iterator, the nodes are designated starting with the first child node and moving the cursor as per the function Next_Sibling; when used as a reverse iterator, the nodes are designated starting with the last child node and moving the cursor as per the function Previous_Sibling. Tampering with the cursors of Container is prohibited while the iterator object exists (in particular, in the @fa<sequence_of_statements> of the @fa<loop_statement> whose @fa<iterator_specification> denotes this object). The iterator object needs finalization.> @dby @xindent<Iterate_Children returns an iterator object (see 5.5.1) that will generate a value for a loop parameter (see 5.5.2) designating each child node of Parent. When used as a forward iterator, the nodes are designated starting with the first child node and moving the cursor as per the function Next_Sibling; when used as a reverse iterator, the nodes are designated starting with the last child node and moving the cursor as per the function Previous_Sibling; when used as a parallel iterator, processing all child nodes concurrently. Tampering with the cursors of Container is prohibited while the iterator object exists (in particular, in the @fa<sequence_of_statements> of the @fa<loop_statement> whose @fa<iterator_specification> denotes this object). The iterator object needs finalization.>
!corrigendum A.18.18(6/3)
!AI-0112-1
!AI-0399-1
@drepl @xcode< @b<type> Holder @b<is tagged private>;
@b<pragma> Preelaborable_Initialization (Holder);>
@dby @xcode< @b<type> Holder @b<is tagged private>
@b<with> Stable_Properties =@> (Is_Empty,
Tampering_With_The_Element_Prohibited),
Default_Initial_Condition =@> Is_Empty (Holder), Preelaborable_Initialization;>
!corrigendum A.18.18(8/3)
!AI-0112-1
!AI-0339-1
@dinsa @xcode< @b<function> "=" (Left, Right : Holder) @b<return> Boolean;> @dinss @xcode< @b<function> Tampering_With_The_Element_Prohibited
(Container : Holder) @b<return> Boolean
@b<with> Nonblocking, Global =@> @b<null>, Use_Formal =@> @b<null>;>
@xcode< @b<function> Empty @b<return> Holder
@b<is> (Empty_Holder) @b<with> Post =@>
@b<not> Tampering_With_The_Element_Prohibited (Empty'Result) @b<and then> Is_Empty (Empty'Result);>
!corrigendum A.18.18(22/3)
!AI-0112-1
!AI-0350-1
@drepl @xcode< @b<procedure> Move (Target : @b<in out> Holder; Source : @b<in out> Holder);> @dby @xcode< @b<procedure> Move (Target : @b<in out> Holder; Source : @b<in out> Holder)
@b<with> Pre =@> (@b<not> Tampering_With_The_Element_Prohibited (Target)
@b<or else raise> Program_Error) @b<and then>
(@b<not> Tampering_With_The_Element_Prohibited (Source)
@b<or else raise> Program_Error),
Post =@> (@b<if not> Target'Has_Same_Storage (Source) @b<then>
Is_Empty (Source) @b<and then> (@b<not> Is_Empty (Target)));>
@xcode< @b<procedure> Swap (Left, Right : @b<in out> Holder)
@b<with> Pre =@> (@b<not> Tampering_With_The_Element_Prohibited (Left)
@b<or else raise> Program_Error) @b<and then>
(@b<not> Tampering_With_The_Element_Prohibited (Right)
@b<or else raise> Program_Error),
Post =@> Is_Empty (Left) = Is_Empty (Right)'Old @b<and then>
Is_Empty (Right) = Is_Empty (Left)'Old;>
!corrigendum A.18.18(67/3)
!AI-0112-1
!AI-0350-1
@drepl @xindent<If Target denotes the same object as Source, then the operation has no effect. Otherwise, the element contained by Source (if any) is removed from Source and inserted into Target, replacing any preexisting content. Source is empty after a successful call to Move.> @dby @xindent<If Target denotes the same object as Source, then the operation has no effect. Otherwise, the element contained by Source (if any) is removed from Source and inserted into Target, replacing any preexisting content.>
@xcode<@b<procedure> Swap (Left, Right : @b<in out> Holder)
@b<with> Pre =@> (@b<not> Tampering_With_The_Element_Prohibited (Left)
@b<or else raise> Program_Error) @b<and then>
(@b<not> Tampering_With_The_Element_Prohibited (Right)
@b<or else raise> Program_Error),
Post =@> Is_Empty (Left) = Is_Empty (Right)'Old @b<and then>
Is_Empty (Right) = Is_Empty (Left)'Old;>
@xindent<If Left denotes the same object as Right, then the operation has no effect. Otherwise, operation exchanges the elements (if any) contained by Left and Right.>
!corrigendum A.18.19(5/3)
!AI-0112-1
!AI-0409-1
@drepl @xcode< @b<type> Vector (Capacity : Count_Type) @b<is tagged private>;> @dby @xcode< @b<type> Vector (Capacity : Count_Type) @b<is tagged private>...>
@xbullet<The @fa<aspect_definition> for Preelaborable_Initialization for type Vector is changed to:>
@xcode< Preelaborable_Initialization =@>
Element_Type'Preelaborable_Initialization>
!corrigendum A.18.19(6/3)
!AI-0112-1
!AI-0339-1
@dinsa @xbullet<The type Vector needs finalization if and only if type Element_Type needs finalization.> @dinss @xbullet<Capacity is omitted from the Stable_Properties of type Vector.>
@xbullet<In function Empty, the postcondition is altered to:>
@xcode< Post =@>
Empty'Result.Capacity = Capacity @b<and then> @b<not> Tampering_With_Elements_Prohibited (Empty'Result) @b<and then> @b<not> Tampering_With_Cursors_Prohibited (Empty'Result) @b<and then> Length (Empty'Result) = 0;>
!corrigendum A.18.20(5/3)
!AI-0112-1
!AI-0409-1
@drepl @xcode< @b<type> List (Capacity : Count_Type) @b<is tagged private>;> @dby @xcode< @b<type> List (Capacity : Count_Type) @b<is tagged private>...>
@xbullet<The @fa<aspect_definition> for Preelaborable_Initialization for type List is changed to:>
@xcode< Preelaborable_Initialization =@>
Element_Type'Preelaborable_Initialization>
!corrigendum A.18.21(5/5)
!AI-0112-1
!AI-0409-1
@drepl @xcode< @b<type> Map (Capacity : Count_Type;
Modulus : Hash_Type) @b<is tagged private>;>
@dby @xcode< @b<type> Map (Capacity : Count_Type;
Modulus : Hash_Type) @b<is tagged private>...>
@xbullet<The @fa<aspect_definition> for Preelaborable_Initialization for type Map is changed to:>
@xcode< Preelaborable_Initialization =@>
Element_Type'Preelaborable_Initialization
@b<and>
Key_Type'Preelaborable_Initialization>
!corrigendum A.18.22(5/5)
!AI-0112-1
!AI-0409-1
@drepl @xcode< @b<type> Map (Capacity : Count_Type) @b<is tagged private>;> @dby @xcode< @b<type> Map (Capacity : Count_Type) @b<is tagged private>...>
@xbullet<The @fa<aspect_definition> for Preelaborable_Initialization for type Map is changed to:>
@xcode< Preelaborable_Initialization =@>
Element_Type'Preelaborable_Initialization
@b<and>
Key_Type'Preelaborable_Initialization>
!corrigendum A.18.23(5/5)
!AI-0112-1
!AI-0409-1
@drepl @xcode< @b<type> Set (Capacity : Count_Type;
Modulus : Hash_Type) @b<is tagged private>;>
@dby @xcode< @b<type> Set (Capacity : Count_Type;
Modulus : Hash_Type) @b<is tagged private>...>
@xbullet<The @fa<aspect_definition> for Preelaborable_Initialization for type Set is changed to:>
@xcode< Preelaborable_Initialization =@>
Element_Type'Preelaborable_Initialization>
!corrigendum A.18.24(5/5)
!AI-0112-1
!AI-0409-1
@drepl @xcode< @b<type> Set (Capacity : Count_Type) @b<is tagged private>;> @dby @xcode< @b<type> Set (Capacity : Count_Type) @b<is tagged private>...>
@xbullet<The @fa<aspect_definition> for Preelaborable_Initialization for type Set is changed to:>
@xcode< Preelaborable_Initialization =@>
Element_Type'Preelaborable_Initialization>
!corrigendum A.18.25(5/3)
!AI-0112-1
!AI-0409-1
@drepl @xcode< @b<type> Tree (Capacity : Count_Type) @b<is tagged private>;> @dby @xcode< @b<type> Tree (Capacity : Count_Type) @b<is tagged private>...>
@xbullet<The @fa<aspect_definition> for Preelaborable_Initialization for type Tree is changed to:>
@xcode< Preelaborable_Initialization =@>
Element_Type'Preelaborable_Initialization>
!corrigendum A.18.32(0)
!AI-0254-1
!AI-0350-1
!AI-0409-1
@dinsc
The language-defined generic package Containers.Bounded_Indefinite_Holders provides a private type Holder and a set of operations for that type. It provides the same operations as the package Containers.Indefinite_Holders (see A.18.18), with the difference that the maximum storage is bounded.
@s8<@i<Static Semantics>>
The declaration of the generic library package Containers.Bounded_Indefinite_Holders has the same contents and semantics as Containers.Indefinite_Holders except:
@xbullet<The following is added to the context clause:>
@xcode< @b<with> System.Storage_Elements; @b<use> System.Storage_Elements;> @xbullet<An additional generic parameter follows Element_Type:>
@xcode< Max_Element_Size_in_Storage_Elements : Storage_Count;>
@xbullet<The @fa<aspect_definition> for Preelaborable_Initialization for type Holder is changed to:>
@xcode< Preelaborable_Initialization =@>
Element_Type'Preelaborable_Initialization>
@xbullet<Add to the precondition of To_Holder and Replace_Element:>
@xcode< @b<and then> (New_Item'Size <=
Max_Element_Size_in_Storage_Elements * System.Storage_Unit @b<or else raise> Program_Error)>
@s8<@i<Bounded (Run-Time) Errors>>
It is a bounded error to assign from a bounded holder object while tampering with elements of that object is prohibited. Either Program_Error is raised by the assignment, execution proceeds with the target object prohibiting tampering with elements, or execution proceeds normally.
@s8<@i<Implementation Requirements>>
For each instance of Containers.Indefinite_Holders and each instance of Containers.Bounded_Indefinite_Holders, if the two instances meet the following conditions, then the output generated by the Holder'Output or Holder'Write subprograms of either instance shall be readable by the Holder'Input or Holder'Read of the other instance, respectively:
@xbullet<the Element_Type parameters of the two instances are statically matching subtypes of the same type; and>
@xbullet<the output generated by Element_Type'Output or Element_Type'Write is readable by Element_Type'Input or Element_Type'Read, respectively (where Element_Type denotes the type of the two actual Element_Type parameters).>
@s8<@i<Implementation Advice>>
Bounded holder objects should be implemented without dynamic allocation and any finalization should be trivial unless Element_Type needs finalization.
The Implementation Advice about the Move and Swap operations is deleted for bounded holders; these operations can copy elements as needed.
!corrigendum B.3(65.1/4)
!AI-0411-1
!AI-0427-1
@drepl @xbullet<An Ada enumeration type corresponds to a C enumeration type with corresponding enumeration literals having the same internal codes, provided the internal codes fall within the range of the C int type.> @dby @xbullet<An Ada enumeration type corresponds to a C enumeration type with corresponding enumeration literals having the same internal codes, provided the internal codes fall within the range of the C int type.>
!corrigendum B.3.1(3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<package> Interfaces.C.Strings @b<is>
@b<pragma> Preelaborate(Strings);>
@dby @xcode<@b<package> Interfaces.C.Strings
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum B.3.2(4)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<generic>
@b<type> Index @b<is> (<@>); @b<type> Element @b<is private>; @b<type> Element_Array @b<is array> (Index @b<range> <@>) @b<of aliased> Element; Default_Terminator : Element;
@b<package> Interfaces.C.Pointers @b<is>
@b<pragma> Preelaborate(Pointers);>
@dby @xcode<@b<generic>
@b<type> Index @b<is> (<@>); @b<type> Element @b<is private>; @b<type> Element_Array @b<is array> (Index @b<range> <@>) @b<of aliased> Element; Default_Terminator : Element;
@b<package> Interfaces.C.Pointers
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum B.4(7)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<package> Interfaces.COBOL @b<is>
@b<pragma> Preelaborate(COBOL);>
@dby @xcode<@b<package> Interfaces.COBOL
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum B.5(21)
!AI-0058-1
!AI-0263-1
@drepl An implementation may add additional declarations to the Fortran interface packages. For example, the Fortran interface package for an implementation of Fortran 77 (ANSI X3.9-1978) that defines types like Integer*@i<n>, Real*@i<n>, Logical*@i<n>, and Complex*@i<n> may contain the declarations of types named Integer_Star_@i<n>, Real_Star_@i<n>, Logical_Star_@i<n>, and Complex_Star_@i<n>. (This convention should not apply to Character*@i<n>, for which the Ada analog is the constrained array subtype Fortran_Character (1..n).) Similarly, the Fortran interface package for an implementation of Fortran 90 that provides multiple kinds of intrinsic types, e.g. Integer (Kind=@i<n>), Real (Kind=@i<n>), Logical (Kind=@i<n>), Complex (Kind=@i<n>), and Character (Kind=@i<n>), may contain the declarations of types with the recommended names Integer_Kind_@i<n>, Real_Kind_@i<n>, Logical_Kind_@i<n>, Complex_Kind_@i<n>, and Character_Kind_@i<n>. @dby An implementation may add additional declarations to the Fortran interface packages. For example, declarations are permitted for the character types corresponding to Fortran character kinds 'ascii' and 'iso_10646', which in turn correspond to ISO/IEC 646:1991 and to UCS-4 as specified in ISO/IEC 10646:2017.
!corrigendum C.3.2(2/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> System; @b<with> System.Multiprocessors; @b<package> Ada.Interrupts @b<is>
@b<type> Interrupt_Id @b<is> @ft<@i<implementation-defined>>; @b<type> Parameterless_Handler @b<is>
@b<access protected procedure>;>
@dby @xcode<@b<with> System; @b<with> System.Multiprocessors; @b<package> Ada.Interrupts
@b<with> Nonblocking, Global =@> @b<in out synchronized> @b<is> @b<type> Interrupt_Id @b<is> @ft<@i<implementation-defined>>; @b<type> Parameterless_Handler @b<is>
@b<access protected procedure> @b<with> Nonblocking =@> False;>
!corrigendum C.6(12/3)
!AI-0282-1
!AI-0363-1
@drepl If an atomic object is passed as a parameter, then the formal parameter shall either have an atomic type or allow pass by copy. If an atomic object is used as an actual for a generic formal object of mode @b<in out>, then the type of the generic formal object shall be atomic. If the @fa<prefix> of an @fa<attribute_reference> for an Access attribute denotes an atomic object (including a component), then the designated type of the resulting access type shall be atomic. If an atomic type is used as an actual for a generic formal derived type, then the ancestor of the formal type shall be atomic. Corresponding rules apply to volatile objects and types. @dby If an atomic object is passed as a parameter, then the formal parameter shall either have an atomic type or allow pass by copy. If an atomic object is used as an actual for a generic formal object of mode @b<in out>, then the type of the generic formal object shall be atomic. If the @fa<prefix> of an @fa<attribute_reference> for an Access attribute denotes an atomic object (including a component), then the designated type of the resulting access type shall be atomic. Corresponding rules apply to volatile objects and to full access objects.
!corrigendum C.6(12.1/3)
!AI-0282-1
!AI-0363-1
@drepl If a volatile type is used as an actual for a generic formal array type, then the element type of the formal type shall be volatile. @dby If the Atomic, Atomic_Components, Volatile, Volatile_Components, Independent, Independent_Components, or Full_Access_Only aspect is True for a generic formal type, then that aspect shall be True for the actual type. If an atomic type is used as an actual for a generic formal derived type, then the ancestor of the formal type shall be atomic. A corresponding rule applies to volatile types and similarly to full access types.
If a type with volatile components is used as an actual for a generic formal array type, then the components of the formal type shall be volatile. Furthermore, if the actual type has atomic components and the formal array type has aliased components, then the components of the formal array type shall also be atomic. A corresponding rule applies when the actual type has volatile full access components.
!corrigendum C.6(19)
!AI-0128-1
!AI-0347-1
!AI-0363-1
@dinsa If an actual parameter is atomic or volatile, and the corresponding formal parameter is not, then the parameter is passed by copy. @dinst All reads of or writes to any nonatomic subcomponent of a full access object are performed by reading and/or writing all of the nearest enclosing full access object.
!corrigendum C.6.4
!AI-0321-1
!AI-0364-1
@dinsc
The language-defined generic package System.Atomic_Operations.Integer_Arithmetic provides operations to perform arithmetic atomically on objects of integer types.
@s8<@i<Static Semantics>>
The generic library package System.Atomic_Operations.Integer_Arithmetic has the following declaration:
@xcode<@b<generic>
@b<type> Atomic_Type @b<is range> <@> @b<with> Atomic;
@b<package> System.Atomic_Operations.Integer_Arithmetic
@b<with> Pure, Nonblocking @b<is>>
@xcode< @b<procedure> Atomic_Add (Item : @b<aliased in out> Atomic_Type;
Value : Atomic_Type)
@b<with> Convention =@> Intrinsic;>
@xcode< @b<procedure> Atomic_Subtract (Item : @b<aliased in out> Atomic_Type;
Value : Atomic_Type)
@b<with> Convention =@> Intrinsic;>
@xcode< @b<function> Atomic_Fetch_And_Add
(Item : @b<aliased in out> Atomic_Type;
Value : Atomic_Type) @b<return> Atomic_Type @b<with> Convention =@> Intrinsic;>
@xcode< @b<function> Atomic_Fetch_And_Subtract
(Item : @b<aliased in out> Atomic_Type;
Value : Atomic_Type) @b<return> Atomic_Type @b<with> Convention =@> Intrinsic;>
@xcode< @b<function> Is_Lock_Free (Item : @b<aliased> Atomic_Type) @b<return> Boolean
@b<with> Convention =@> Intrinsic;>
@xcode<@b<end> System.Atomic_Operations.Integer_Arithmetic;>
The operations of this package are defined as follows:
@xcode<@b<procedure> Atomic_Add (Item : @b<aliased in out> Atomic_Type;
Value : Atomic_Type)
@b<with> Convention =@> Intrinsic;>
@xindent<Atomically performs: @fc<Item := Item + Value;>>
@xcode<@b<procedure> Atomic_Subtract (Item : @b<aliased in out> Atomic_Type;
Value : Atomic_Type)
@b<with> Convention =@> Intrinsic;>
@xindent<Atomically performs: @fc<Item := Item - Value;>>
@xcode<@b<function> Atomic_Fetch_And_Add
(Item : @b<aliased in out> Atomic_Type;
Value : Atomic_Type) @b<return> Atomic_Type @b<with> Convention =@> Intrinsic;>
@xindent<Atomically performs: @fc<Tmp := Item; Item := Item + Value; @b<return> Tmp;>>
@xcode<@b<function> Atomic_Fetch_And_Subtract
(Item : @b<aliased in out> Atomic_Type;
Value : Atomic_Type) @b<return> Atomic_Type @b<with> Convention =@> Intrinsic;>
@xindent<Atomically performs: @fc<Tmp := Item; Item := Item - Value; @b<return> Tmp;>>
!corrigendum C.7.1(2/2)
!AI-0241-1
!AI-0302-1
!AI-0399-1
@drepl @xcode<@b<package> Ada.Task_Identification @b<is>
@b<pragma> Preelaborate(Task_Identification); @b<type> Task_Id @b<is private>; @b<pragma> Preelaborable_Initialization (Task_Id); Null_Task_Id : @b<constant> Task_Id; @b<function> "=" (Left, Right : Task_Id) @b<return> Boolean;>
@dby @xcode<@b<package> Ada.Task_Identification
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is> @b<type> Task_Id @b<is private>
@b<with> Preelaborable_Initialization;
Null_Task_Id : @b<constant> Task_Id; @b<function> "=" (Left, Right : Task_Id) @b<return> Boolean;>
!corrigendum C.7.2(2)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> Ada.Task_Identification; @b<use> Ada.Task_Identification; @b<generic>
@b<type> Attribute @b<is private>; Initial_Value : @b<in> Attribute;
@b<package> Ada.Task_Attributes @b<is>> @dby @xcode<@b<with> Ada.Task_Identification; @b<use> Ada.Task_Identification; @b<generic>
@b<type> Attribute @b<is private>; Initial_Value : @b<in> Attribute;
@b<package> Ada.Task_Attributes
@b<with> Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum C.7.3(2/2)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> Ada.Task_Identification; @b<with> Ada.Exceptions; @b<package> Ada.Task_Termination @b<is>
@b<pragma> Preelaborate(Task_Termination);>
@dby @xcode<@b<with> Ada.Task_Identification; @b<with> Ada.Exceptions; @b<package> Ada.Task_Termination
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum D.2.1(1.2/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<package> Ada.Dispatching @b<is>
@b<pragma> Preelaborate(Dispatching);>
@dby @xcode<@b<package> Ada.Dispatching
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum D.2.1(1.5/2)
!AI-0279-1
!AI-0294-1
@dinsa Dispatching serves as the parent of other language-defined library units concerned with task dispatching. @dinss For a noninstance subprogram (including a generic formal subprogram), a generic subprogram, or an entry, the following language-defined aspect may be specified with an @fa<aspect_specification> (see 13.1.1):
@xhang<@xterm<Yield> The type of aspect Yield is Boolean.>
@xindent<If directly specified, the @fa<aspect_definition> shall be a static expression. If not specified (including by inheritance), the aspect is False.>
@xindent<If a Yield aspect is specified True for a primitive subprogram @i<S> of a type @i<T>, then the aspect is inherited by the corresponding primitive subprogram of each descendant of @i<T>.>
@s8<@i<Legality Rules>>
If the Yield aspect is specified for a dispatching subprogram that inherits the aspect, the specified value shall be confirming.
If the Nonblocking aspect (see 9.5) of the associated callable entity is statically True, the Yield aspect shall not be specified as True. For a callable entity that is declared within a generic body, this rule is checked assuming that any nonstatic Nonblocking attributes in the expression of the Nonblocking aspect of the entity are statically True.
In addition to the places where Legality Rules normally apply (see 12.3), these rules also apply in the private part of an instance of a generic unit.
!corrigendum D.2.1(7/3)
!AI-0241-1
!AI-0279-1
!AI-0299-1
@drepl A call of Yield is a task dispatching point. Yield is a potentially blocking operation (see 9.5.1). @dby A call of Yield and a @fa<delay_statement> are task dispatching points for all language-defined policies.
If the Yield aspect has the value True, then a call to procedure Yield is included within the body of the associated callable entity, and invoked immediately prior to returning from the body if and only if no other task dispatching points were encountered during the execution of the body.
!corrigendum D.2.4(2.2/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<package> Ada.Dispatching.Non_Preemptive @b<is>
@b<pragma> Preelaborate(Non_Preemptive); @b<procedure> Yield_To_Higher; @b<procedure> Yield_To_Same_Or_Higher @b<renames> Yield;
@b<end> Ada.Dispatching.Non_Preemptive;> @dby @xcode<@b<package> Ada.Dispatching.Non_Preemptive
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is> @b<procedure> Yield_To_Higher; @b<procedure> Yield_To_Same_Or_Higher @b<renames> Yield;
@b<end> Ada.Dispatching.Non_Preemptive;>
!corrigendum D.2.5(4/2)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> System; @b<with> Ada.Real_Time; @b<package> Ada.Dispatching.Round_Robin @b<is>
Default_Quantum : @b<constant> Ada.Real_Time.Time_Span :=
@ft<@i<implementation-defined>>;
@b<procedure> Set_Quantum (Pri : @b<in> System.Priority;
Quantum : @b<in> Ada.Real_Time.Time_Span);
@b<procedure> Set_Quantum (Low, High : @b<in> System.Priority;
Quantum : @b<in> Ada.Real_Time.Time_Span);
@b<function> Actual_Quantum (Pri : System.Priority)
@b<return> Ada.Real_Time.Time_Span;
@b<function> Is_Round_Robin (Pri : System.Priority) @b<return> Boolean;
@b<end> Ada.Dispatching.Round_Robin;> @dby @xcode<@b<with> System; @b<with> Ada.Real_Time; @b<package> Ada.Dispatching.Round_Robin
@b<with> Nonblocking, Global =@> @b<in out synchronized> @b<is> Default_Quantum : @b<constant> Ada.Real_Time.Time_Span :=
@ft<@i<implementation-defined>>;
@b<procedure> Set_Quantum (Pri : @b<in> System.Priority;
Quantum : @b<in> Ada.Real_Time.Time_Span);
@b<procedure> Set_Quantum (Low, High : @b<in> System.Priority;
Quantum : @b<in> Ada.Real_Time.Time_Span);
@b<function> Actual_Quantum (Pri : System.Priority)
@b<return> Ada.Real_Time.Time_Span;
@b<function> Is_Round_Robin (Pri : System.Priority) @b<return> Boolean;
@b<end> Ada.Dispatching.Round_Robin;>
!corrigendum D.2.6(9/2)
!AI-0230-1
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> Ada.Real_Time; @b<with> Ada.Task_Identification; @b<package> Ada.Dispatching.EDF @b<is>
@b<subtype> Deadline @b<is> Ada.Real_Time.Time; Default_Deadline : @b<constant> Deadline :=
Ada.Real_Time.Time_Last;
@b<procedure> Set_Deadline (D : @b<in> Deadline;
T : @b<in> Ada.Task_Identification.Task_Id := Ada.Task_Identification.Current_Task);
@b<procedure> Delay_Until_And_Set_Deadline (
Delay_Until_Time : @b<in> Ada.Real_Time.Time; Deadline_Offset : @b<in> Ada.Real_Time.Time_Span);
@b<function> Get_Deadline (T : Ada.Task_Identification.Task_Id :=
Ada.Task_Identification.Current_Task) @b<return> Deadline;
@b<end> Ada.Dispatching.EDF;> @dby @xcode<@b<with> Ada.Real_Time; @b<with> Ada.Task_Identification; @b<package> Ada.Dispatching.EDF
@b<with> Nonblocking, Global =@> @b<in out synchronized> @b<is> @b<subtype> Deadline @b<is> Ada.Real_Time.Time; @b<subtype> Relative_Deadline @b<is> Ada.Real_Time.Time_Span; Default_Deadline : @b<constant> Deadline :=
Ada.Real_Time.Time_Last;
Default_Relative_Deadline : @b<constant> Relative_Deadline :=
Ada.Real_Time.Time_Span_Last;
@b<procedure> Set_Deadline
(D : @b<in> Deadline;
T : @b<in> Ada.Task_Identification.Task_Id := Ada.Task_Identification.Current_Task);
@b<function> Get_Deadline
(T : Ada.Task_Identification.Task_Id := Ada.Task_Identification.Current_Task) @b<return> Deadline;
@b<procedure> Set_Relative_Deadline
(D : @b<in> Relative_Deadline; T : @b<in> Ada.Task_Identification.Task_Id := Ada.Task_Identification.Current_Task);
@b<function> Get_Relative_Deadline
(T : Ada.Task_Identification.Task_Id := Ada.Task_Identification.Current_Task) @b<return> Relative_Deadline;
@b<procedure> Delay_Until_And_Set_Deadline
(Delay_Until_Time : @b<in> Ada.Real_Time.Time; Deadline_Offset : @b<in> Ada.Real_Time.Time_Span) @b<with> Nonblocking =@> False;
@b<function> Get_Last_Release_Time
(T : Ada.Task_Identification.Task_Id := Ada.Task_Identification.Current_Task) @b<return> Ada.Real_Time.Time;
@b<end> Ada.Dispatching.EDF;>
!corrigendum D.3(13)
!AI-0230-1
!AI-0404-1
@dinsa @xbullet<When a task calls a protected operation, a check is made that its active priority is not higher than the ceiling of the corresponding protected object; Program_Error is raised if this check fails.> @dinss If the task dispatching policy specified for the ceiling priority of a protected object is EDF_Within_Priorities, the following additional rules apply:
@xbullet<Every protected object has a @i<relative deadline>, which is determined by a Relative_Deadline aspect as defined in D.2.6, or by assignment to the Relative_Deadline attribute as described in D.5.2. The relative deadline of a protected object represents a lower bound on the relative deadline a task may have when it calls a protected operation of that protected object.>
@xbullet<If aspect Relative_Deadline is not specified for a protected type then the initial relative deadline of the corresponding protected object is Ada.Real_Time.Time_Span_Zero.>
@xbullet<While a task executes a protected action on a protected object @i<P>, it inherits the relative deadline of @i<P>. In this case, let @i<DF> be 'now' ('now' is obtained via a call on Ada.Real_Time.Clock at the start of the action) plus the deadline floor of @i<P>. If the active deadline of the task is later than @i<DF>, its active deadline is reduced to @i<DF>; the active deadline is unchanged otherwise.>
@xbullet<When a task calls a protected operation, a check is made that its active deadline minus its last release time is not less than the relative deadline of the corresponding protected object; Program_Error is raised if this check fails.>
!corrigendum D.4(7/2)
!AI-0163-1
!AI-0183-1
@drepl Two queuing policies, FIFO_Queuing and Priority_Queuing, are language defined. If no Queuing_Policy pragma applies to any of the program units comprising the partition, the queuing policy for that partition is FIFO_Queuing. The rules for this policy are specified in 9.5.3 and 9.7.1. @dby Three queuing policies, FIFO_Queuing, Ordered_FIFO_Queuing, and Priority_Queuing, are language defined. If no Queuing_Policy pragma applies to any of the program units comprising the partition, the queuing policy for that partition is FIFO_Queuing. The rules for the FIFO_Queuing policy are specified in 9.5.3 and 9.7.1.
The Ordered_FIFO_Queuing policy is defined as follows:
@xbullet<Calls are selected on a given entry queue in order of arrival.>
@xbullet<When more than one condition of an @fa<entry_barrier> of a protected object becomes True, and more than one of the respective queues is nonempty, the call that arrived first is selected.>
@xbullet<If the expiration time of two or more open @fa<delay_alternative>s is the same and no other @fa<accept_alternative>s are open, the @fa<sequence_of_statements> of the @fa<delay_alternative> that is first in textual order in the @fa<selective_accept> is executed.>
@xbullet<When more than one alternative of a @fa<selective_accept> is open and has queued calls, the alternative whose queue has the call that arrived first is selected.>
!corrigendum D.4(16)
!AI-0164-1
!AI-0388-1
@dinsa The implementation should use names that end with "_Queuing" for implementation-defined queuing policies. @dinss @s8<@i<Static Semantics>>
For a task type (including the anonymous type of a @fa<single_task_declaration>), protected type (including the anonymous type of a @fa<single_protected_declaration>), or an @fa<entry_declaration>, the following language-defined representation aspect may be specified:
@xhang<@xterm<Max_Entry_Queue_Length> The type of aspect Max_Entry_Queue_Length is Integer.>
@xindent<If directly specified, the aspect_definition shall be a static expression no less than -1. If not specified, the aspect has value -1 (representing no additional restriction on queue length).>
@s8<@i<Legality Rules>>
If the Max_Entry_Queue_Length aspect for a type has a nonnegative value, the Max_Entry_Queue_Length aspect for every individual entry of that type shall not be greater than the value of the aspect for the type. The Max_Entry_Queue_Length aspect of a type is nonoverridable (see 13.1.1).
@s8<@i<Post-Compilation Rules>>
If a restriction Max_Entry_Queue_Length applies to a partition, any value specified for the Max_Entry_Queue_Length aspect specified for the declaration of a type or entry in the partition shall not be greater than the value of the restriction.
@s8<@i<Dynamic Semantics>>
If a nonconfirming value is specified for Max_Entry_Queue_Length for a type, and an entry call or requeue would cause the queue for any entry of the type to become longer than the specified value, then Program_Error is raised at the point of the call or requeue.
If a nonconfirming value is specified for Max_Entry_Queue_Length for an entry, and an entry call or requeue would cause the queue for an entry to become longer than the specified value, then Program_Error is raised at the point of the call or requeue.
!corrigendum D.5.1(3/2)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> System; @b<with> Ada.Task_Identification; @ft<@i<-- See C.7.1>> @b<package> Ada.Dynamic_Priorities @b<is>
@b<pragma> Preelaborate(Dynamic_Priorities);>
@dby @xcode<@b<with> System; @b<with> Ada.Task_Identification; @ft<@i<-- See C.7.1>> @b<package> Ada.Dynamic_Priorities
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum D.7(2)
!AI-0290-1
!AI-0369-1
@dinsb The following @i<restriction_>@fa<identifier>s are language-defined: @dinss A scalar @fa<expression> within a protected unit is said to be @i<pure-barrier-eligible> if it is one of the following: @xbullet<a static expression;> @xbullet<a @fa<name> that statically names (see 4.9) a scalar subcomponent of the immediately enclosing protected unit;> @xbullet<a Count @fa<attribute_reference> whose @fa<prefix> statically denotes an entry declaration of the immediately enclosing unit;> @xbullet<a call to a predefined relational operator or boolean logical operator (@b<and>, @b<or>, @b<xor>, @b<not>), where each operand is pure-barrier-eligible;> @xbullet<a membership test whose @i<tested_>@fa<simple_expression> is pure-barrier-eligible, and whose @fa<membership_choice_list> meets the requirements for a static membership test (see 4.9);> @xbullet<a short-circuit control form both of whose operands are pure-barrier-eligible;> @xbullet<a @fa<conditional_expression> all of whose @fa<condition>s, @i<selecting_>@fa<expression>s, and @i<dependent_>@fa<expression>s are pure-barrier-eligible; or> @xbullet<a pure-barrier-eligible @fa<expression> enclosed in parentheses.>
!corrigendum D.8(3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<package> Ada.Real_Time @b<is>> @dby @xcode<@b<package> Ada.Real_Time
@b<with> Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum D.10(3/2)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<package> Ada.Synchronous_Task_Control @b<is>
@b<pragma> Preelaborate(Synchronous_Task_Control);>
@dby @xcode<@b<package> Ada.Synchronous_Task_Control
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum D.10(5.2/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> Ada.Real_Time; @b<package> Ada.Synchronous_Task_Control.EDF @b<is>
@b<procedure> Suspend_Until_True_And_Set_Deadline
(S : @b<in out> Suspension_Object;
TS : @b<in> Ada.Real_Time.Time_Span);
@b<end> Ada.Synchronous_Task_Control.EDF;> @dby @xcode<@b<with> Ada.Real_Time; @b<package> Ada.Synchronous_Task_Control.EDF
@b<with> Nonblocking, Global =@> @b<in out synchronized> @b<is> @b<procedure> Suspend_Until_True_And_Set_Deadline
(S : @b<in out> Suspension_Object;
TS : @b<in> Ada.Real_Time.Time_Span)
@b<with> Nonblocking =@> False;
@b<end> Ada.Synchronous_Task_Control.EDF;>
!corrigendum D.10.1(3/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<package> Ada.Synchronous_Barriers @b<is>
@b<pragma> Preelaborate(Synchronous_Barriers);>
@dby @xcode<@b<package> Ada.Synchronous_Barriers
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum D.11(3/2)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> Ada.Task_Identification; @b<package> Ada.Asynchronous_Task_Control @b<is>
@b<pragma> Preelaborate(Asynchronous_Task_Control); @b<procedure> Hold(T : @b<in> Ada.Task_Identification.Task_Id); @b<procedure> Continue(T : @b<in> Ada.Task_Identification.Task_Id); @b<function> Is_Held(T : Ada.Task_Identification.Task_Id)
@b<return> Boolean;
@b<end> Ada.Asynchronous_Task_Control;> @dby @xcode<@b<with> Ada.Task_Identification; @b<package> Ada.Asynchronous_Task_Control
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is> @b<procedure> Hold(T : @b<in> Ada.Task_Identification.Task_Id); @b<procedure> Continue(T : @b<in> Ada.Task_Identification.Task_Id); @b<function> Is_Held(T : Ada.Task_Identification.Task_Id)
@b<return> Boolean;
@b<end> Ada.Asynchronous_Task_Control;>
!corrigendum D.14(3/2)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> Ada.Task_Identification; @b<with> Ada.Real_Time; @b<use> Ada.Real_Time; @b<package> Ada.Execution_Time @b<is>> @dby @xcode<@b<with> Ada.Task_Identification; @b<with> Ada.Real_Time; @b<use> Ada.Real_Time; @b<package> Ada.Execution_Time
@b<with> Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum D.14.1(3/2)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> System; @b<package> Ada.Execution_Time.Timers @b<is>> @dby @xcode<@b<with> System; @b<package> Ada.Execution_Time.Timers
@b<with> Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum D.14.2(3/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> System; @b<with> System.Multiprocessors; @b<package> Ada.Execution_Time.Group_Budgets @b<is>> @dby @xcode<@b<with> System; @b<with> System.Multiprocessors; @b<package> Ada.Execution_Time.Group_Budgets
@b<with> Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum D.14.3(3/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> Ada.Interrupts; @b<package> Ada.Execution_Time.Interrupts @b<is>
@b<function> Clock (Interrupt : Ada.Interrupts.Interrupt_Id)
@b<return> CPU_Time;
@b<function> Supported (Interrupt : Ada.Interrupts.Interrupt_Id)
@b<return> Boolean;
@b<end> Ada.Execution_Time.Interrupts;> @dby @xcode<@b<with> Ada.Interrupts; @b<package> Ada.Execution_Time.Interrupts
@b<with> Nonblocking, Global =@> @b<in out synchronized> @b<is> @b<function> Clock (Interrupt : Ada.Interrupts.Interrupt_Id)
@b<return> CPU_Time;
@b<function> Supported (Interrupt : Ada.Interrupts.Interrupt_Id)
@b<return> Boolean;
@b<end> Ada.Execution_Time.Interrupts;>
!corrigendum D.15(3/2)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<package> Ada.Real_Time.Timing_Events @b<is>> @dby @xcode<@b<package> Ada.Real_Time.Timing_Events
@b<with> Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum D.16(3/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<package> System.Multiprocessors @b<is>
@b<pragma> Preelaborate(Multiprocessors);>
@dby @xcode<@b<package> System.Multiprocessors
@b<with> Preelaborate, Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum D.16(14/3)
!AI-0281-1
!AI-0321-1
@drepl The CPU value determines the processor on which the task will activate and execute; the task is said to be assigned to that processor. If the CPU value is Not_A_Specific_CPU, then the task is not assigned to a processor. A task without a CPU aspect specified will activate and execute on the same processor as its activating task if the activating task is assigned a processor. If the CPU value is not in the range of System.Multiprocessors.CPU_Range or is greater than Number_Of_CPUs the task is defined to have failed, and it becomes a completed task (see 9.2). @dby For a task, the CPU value determines the processor on which the task will activate and execute; the task is said to be assigned to that processor. If the CPU value is Not_A_Specific_CPU, then the task is not assigned to a processor. A task without a CPU aspect specified will activate and execute on the same processor as its activating task if the activating task is assigned a processor. If the CPU value is not in the range of System.Multiprocessors.CPU_Range or is greater than Number_Of_CPUs the task is defined to have failed, and it becomes a completed task (see 9.2).
For a protected type, the CPU value determines the processor on which calling tasks will execute; the protected object is said to be assigned to that processor. If the CPU value is Not_A_Specific_CPU, then the protected object is not assigned to a processor. A call to a protected object that is assigned to a processor from a task that is not assigned a processor or is assigned a different processor raises Program_Error.
@s8<@i<Implementation Advice>>
Starting a protected action on a protected object statically assigned to a processor should be implemented without busy-waiting.
!corrigendum D.16.1(3/3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> Ada.Real_Time; @b<with> Ada.Task_Identification; @b<package> System.Multiprocessors.Dispatching_Domains @b<is>> @dby @xcode<@b<with> Ada.Real_Time; @b<with> Ada.Task_Identification; @b<package> System.Multiprocessors.Dispatching_Domains
@b<with> Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum E.5(3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<with> Ada.Streams; -- @ft<@i<see 13.13.1>> @b<package> System.RPC @b<is>> @dby @xcode<@b<with> Ada.Streams; -- @ft<@i<see 13.13.1>> @b<package> System.RPC
@b<with> Nonblocking =@> False, Global =@> @b<in out synchronized> @b<is>>
!corrigendum F.3.3(3)
!AI-0241-1
!AI-0302-1
@drepl @xcode<@b<package> Ada.Text_IO.Editing @b<is>> @dby @xcode<@b<package> Ada.Text_IO.Editing
@b<with> Nonblocking, Global =@> @b<in out synchronized> @b<is>>
!corrigendum H.4(23)
!AI-0020-1
!AI-0079-3
!AI-0340-1
!AI-0380-1
@dinsa @xhang<@xterm<No_Reentrancy>During the execution of a subprogram by a task, no other task invokes the same subprogram.> @dinss
@xhang<@xterm<No_Unspecified_Globals>No library-level entity shall have a Global aspect of Unspecified, either explicitly or by default. No library-level entity shall have a Global'Class aspect of Unspecified, explicitly or by default, if it is used as part of a dispatching call.>
@xhang<@xterm<No_Hidden_Indirect_Globals>When within a context where an applicable global aspect is neither Unspecified nor @b<in out all>, any execution within such a context does neither of the following:>
@xinbull<Update (or return a writable reference to) a variable that is reachable via a sequence of zero or more dereferences of access-to-object values from a parameter of a visibly access-to-constant type, from a part of a non-access-type formal parameter of mode @b<in> (after any @b<overriding> @endash see H.7), or from a global that has mode @b<in> or is not within the applicable global variable set, unless the initial dereference is of a part of a formal parameter or global that is visibly of an access-to-variable type;>
@xinbull<Read (or return a readable reference to) a variable that is reachable via a sequence of zero or more dereferences of access-to-object values from a global that is not within the applicable global variable set, unless the initial dereference is of a part of a formal parameter or global that is visibly of an access-to-object type.>
@xindent<For the purposes of the above rules:>
@xinbull<a part of an object is @i<visibly of an access type> if the type of the object is declared immediately within the visible part of a package specification, and at the point of declaration of the type the part is visible and of an access type;>
@xinbull<a function @i<returns a writable reference to V> if it returns a result with a part that is visibly of an access-to-variable type designating @i<V>; similarly, a function @i<returns a readable reference to V> if it returns a result with a part that is visibly of an access-to-constant type designating @i<V>;>
@xinbull<if an applicable global variable set includes a package name, and the collection of some pool-specific access type (see 7.6.1) is implicitly declared in a part of the declarative region of the package included within the global variable set, then all objects allocated from that collection are considered included within the global variable set.>
@xindent<The consequences of violating the No_Hidden_Indirect_Globals restriction is implementation-defined. Any aspects or other means for identifying such violations prior to or during execution are implementation-defined.>
@s8<@i<Dynamic Semantics>>
The following @i<restriction_parameter_>@fa<identifier> is language defined:
@xhang<@xterm<Max_Image_Length> Specifies the maximum length for the result of an Image, Wide_Image, or Wide_Wide_Image attribute. Violation of this restriction results in the raising of Program_Error at the point of the invocation of an image attribute.>
!corrigendum H.4(23.8/2)
!AI-0020-1
!AI-0340-1
@dinsa @xbullet<Max_Tasks =@> 0.> @dinst If a Max_Image_Length restriction applies to any compilation unit in the partition, then for any subtype S, S'Image, S'Wide_Image, and S'Wide_Wide_Image shall be implemented within that partition without any dynamic allocation.
!corrigendum H.4.1(0)
!AI-0256-1
!AI-0403-1
!AI-0407-1
@dinsc
@s8<@i<Static Semantics>>
For a type, the following type-related, operational aspect may be specified:
@xhang<@xterm<No_Controlled_Parts> The type of this aspect is Boolean. If True, the type and any descendants shall not have any controlled parts. If specified, the value of the expression shall be static. If not specified, the value of this aspect is False.>
The No_Controlled_Parts aspect is nonoverridable (see 13.1.1).
@s8<@i<Legality Rules>>
If No_Controlled_Parts is True for a type, no component of the type shall have a controlled part nor shall the type itself be controlled. For the purposes of this rule, a type has a controlled part if its full type has a controlled part; this is applied recursively. In addition to the places where Legality Rules normally apply (see 12.3), this rule also applies in the private part of an instance of a generic unit.
When enforcing the above rule within a generic body @i<G> or within the body of a generic unit declared within the declarative region of generic unit @i<G>, a generic formal private type of @i<G> and a generic formal derived type of @i<G> whose ancestor is a tagged type whose No_Controlled_Parts aspect is False are considered to have a controlled part.
!corrigendum H.5(5/2)
!AI-0247-1
!AI-0267-1
@drepl An implementation is required to detect a potentially blocking operation within a protected operation, and to raise Program_Error (see 9.5.1). @dby An implementation is required to detect a potentially blocking operation that occurs during the execution of a protected operation or a parallel construct defined within a compilation unit to which the pragma applies, and to raise Program_Error (see 9.5).
!corrigendum H.7(0)
!AI-0079-3
!AI-0380-1
!AI-0431-1
@dinsc In addition to the entities specified in 6.1.2, the Global aspect may be specified for a subtype (including a formal subtype), formal package, formal subprogram, and formal object of an anonymous access-to-subprogram type.
@s8<@i<Syntax>>
The following additional syntax is provided to override the mode of a formal parameter to reflect indirect effects on variables reachable from the formal parameter by one or more access-value dereferences:
@xindent<@fa<extended_global_mode>@fa<@ ::=@ >@hr @ @ @ @ @b<overriding> @fa<basic_global_mode>>
@s8<@i<Name Resolution Rules>>
The @i<object_>@fa<name> that is associated with an @b<overriding> mode shall resolve to statically denote a formal object, or a formal parameter of the associated entity.
@s8<@i<Static Semantics>>
The presence of the reserved word @b<overriding> in a global mode indicates that the specification is overriding the mode of a formal parameter with another mode to reflect the overall effect of an invocation of the callable entity on the state associated with the corresponding actual parameter.
As described in 6.1.2, the following rules are defined in terms of operations that are performed by or on behalf of an entity.
The Global aspect for a subtype identifies the global variables that might be referenced during default initialization, adjustment as part of assignment, finalization of an object of the subtype, or conversion to the subtype, including the evaluation of any assertion expressions that apply. If not specified for the first subtype of a derived type, the aspect defaults to that of the ancestor subtype; if not specified for a nonderived composite first subtype the aspect defaults to that of the enclosing library unit; if not specified for a nonderived elementary first subtype (or scalar base subtype), the aspect defaults to @b<null> in the absence of a predicate (or when the predicate is statically True), and to that of the enclosing library unit otherwise. If not specified for a nonfirst subtype @i<S>, the Global aspect defaults to that of the subtype identified in the @fa<subtype_indication> defining @i<S>.
The Global'Class aspect may be specified for the first subtype of a tagged type @i<T>, indicating an upper bound on the Global aspect of any descendant of @i<T>. If not specified, it defaults to Unspecified.
@s8<@i<Legality Rules>>
For a tagged subtype @i<T>, each mode of its Global aspect shall identify a subset of the variables identified either by the corresponding mode, or by the @b<in out> mode, of the Global'Class aspect of the first subtype of any ancestor of @i<T>.
!corrigendum H.7.1(0)
!AI-0380-1
!AI-0404-1
@dinsc The Use_Formal and Dispatching aspects are provided to more precisely describe the use of generic formal parameters and dispatching calls within the execution of an operation, enabling more precise checking of conformance with the Nonblocking and global aspects that apply at the point of invocation of the operation.
For any declaration within a generic unit for which a global or Nonblocking aspect may be specified, other than a @fa<generic_formal_parameter_declaration>, the following aspect may be specified to indicate which generic formal parameters are @i<used> by the associated entity:
@xhang<@xterm<Use_Formal>The aspect is specified with a @fa<formal_parameter_set>, with the following form:>
@xindent<@fa<formal_parameter_set>@fa<@ ::=@ >@hr @ @ @ @ @fa<formal_group_designator>@hr @ @ |@ @fa<formal_parameter_name>@hr @ @ |@ (@fa<formal_parameter_name>{, @fa<formal_parameter_name>})>
@xindent<@fa<formal_group_designator>@fa<@ ::=@ >@b<null> | @b<all>>
@xindent<@fa<formal_parameter_name>@fa<@ ::=@ >@hr @ @ @ @ @i<formal_>@fa<subtype_mark>@hr @ @ |@ @i<formal_subprogram_>@fa<name>@hr @ @ |@ @i<formal_access_to_subprogram_object_>@fa<name>>
For any declaration for which a global or Nonblocking aspect may be specified, other than for a library package, a generic library package, or a generic formal, the following aspect may be specified:
@xhang<@xterm<Dispatching>The aspect is specified with a @fa<dispatching_operation_set>, with the following form:>
@xindent<@fa<dispatching_operation_set>@fa<@ ::=@ >@hr @ @ @ @ @fa<dispatching_operation_specifier>@hr @ @ |@ (@fa<dispatching_operation_specifier>{, @fa<dispatching_operation_specifier>})>
@xindent<@fa<dispatching_operation_specifier>@fa<@ ::=@ >@hr @ @ @ @ @i<dispatching_operation_>@fa<name> (@i<object_>@fa<name>)>
@s8<@i<Name Resolution Rules>>
A @fa<formal_parameter_name> in a Use_Formal aspect shall resolve to statically denote a formal subtype, a formal subprogram, or a formal object of an anonymous access-to-subprogram type of an enclosing generic unit or visible formal package.
The @i<object_>@fa<name> of a @fa<dispatching_operation_specifier> shall resolve to statically name an object (including possibly a formal parameter) of a tagged class-wide type @i<T>'Class, or of an access type designating a tagged class-wide type @i<T>'Class; the @i<dispatching_operation_>@fa<name> of the @fa<dispatching_operation_specifier> shall resolve to statically denote a dispatching operation associated with @i<T>.
@s8<@i<Static Semantics>>
The @i<formal parameter set> is identified by a set of @fa<formal_parameter_name>s. Alternatively, the reserved word @b<null> may be used to indicate none of the generic formal parameters, or @b<all> to indicate all of the generic formal parameters, of any enclosing generic unit (or visible formal package) might be used within the execution of the operation. If there is no formal parameter set specified for an entity declared within a generic unit, it defaults to @b<all>.
The @i<dispatching operation set> is identified by a set of @fa<dispatching_operation_specifier>s. It indicates that the Nonblocking and global effects of dispatching calls that match one of the specifiers need not be accounted for by the Nonblocking or global aspect, but are instead to be accounted for by the invoker of the operation. A dispatching call matches a @fa<dispatching_operation_specifier> if the @fa<name> or @fa<prefix> of the call statically denotes the same operation(s) as that of the @fa<dispatching_operation_specifier>, and at least one of the objects controlling the call is denoted by, or designated by, a @fa<name> that statically names the same object as that denoted by the @i<object_>@fa<name> of the @fa<dispatching_operation_specifier>.
In the absence of any @fa<dispatching_operation_specifier>s, or if none of them match a dispatching call @i<C> within an operation @i<P>, Nonblocking and global aspects checks are performed at the point of the call @i<C> within @i<P> using the Nonblocking and Global'Class aspects that apply to the dispatching operation named in call @i<C>. If there is a match, any global access or potential blocking within the subprogram body invoked by the call @i<C> is ignored at the point of call within @i<P>. Instead, when the operation @i<P> itself is invoked, Nonblocking and global aspect checks are performed presuming each named dispatching operation is called at least once (with the named object controlling the call), but similarly ignoring those dispatching calls that would match a @fa<dispatching_operation_specifier> applicable at the point of invocation of @i<P>.
@s8<@i<Legality Rules>>
Within an operation to which a Use_Formal aspect applies, if the formal parameter set is anything but @b<all>, then the only generic formal subtypes that may be used, the only formal subprograms that may be called, and the only formal objects of an anonymous access-to-subprogram type that may be dereferenced as part of a call or passed as the actual for an access parameter, are those included in the formal parameter set.
When an operation (or instance thereof) to which a Use_Formal aspect applies is invoked, Nonblocking and global aspect checks are performed presuming each generic formal parameter (or corresponding actual parameter) of the formal parameter set is used at least once.
@s8<@i<Examples>>
@i<An example of use of the Dispatching aspect:>
@xcode<@b<procedure> My_Write( -- @ft<@i<see 13.13.2>>
Stream : @b<not null access> Ada.Streams.Root_Stream_Type'Class; Item : My_Integer'Base) @b<with> Dispatching =@> Write(Stream);
@b<for> My_Integer'Write @b<use> My_Write;>
@i<For examples of use of the Use_Formal aspect, see the Element functions of Hashed_Sets in A.18.8.>
!corrigendum J.15.14(0)
!AI-0409-1
!AI-0417-1
@dinsc
This subclause defines pragmas that specify aspects that help control the elaboration order of @fa<library_item>s.
@s8<@i<Syntax>>
The following @fa<pragma>s are defined with the given forms:
@xindent<@ @ @b<pragma> Preelaborate[(@i<library_unit_>@fa<name>)];>
@xindent<@ @ @b<pragma> Preelaborable_Initialization(@fa<direct_name>);>
@xindent<@ @ @b<pragma> Pure[(@i<library_unit_>@fa<name>)];>
@xindent<@ @ @b<pragma> Elaborate_Body[(@i<library_unit_>@fa<name>)];>
@xindent<@fa<Pragma>s Preelaborate, Pure, and Elaborate_Body are library unit pragmas.>
@s8<@i<Static Semantics>>
A @fa<pragma> Preelaborate specifies that a library unit is preelaborated, namely that the Preelaborate aspect (see 10.2.1) of the library unit is True.
A @fa<pragma> Pure specifies that a library unit is declared pure, namely that the Pure aspect (see 10.2.1) of the library unit is True.
A @fa<pragma> Elaborate_Body specifies that a library unit requires a completion, namely that the Elaborate_Body aspect (see 10.2.1) of the library unit is True.
@s8<@i<Legality Rules>>
A @fa<pragma> Preelaborable_Initialization specifies that the Preelaborable_Initialization aspect (see 10.2.1) for a composite type is True. This pragma shall appear in the visible part of a package or generic package.
If the pragma appears in the first declaration list of a @fa<package_specification>, then the @fa<direct_name> shall denote the first subtype of a composite type, and the type shall be declared immediately within the same package as the pragma. The composite type shall be one for which the Preelaborable_Initialization aspect can be directly specified as True. In addition to the places where Legality Rules normally apply (see 12.3), these rules also apply in the private part of an instance of a generic unit.
If the pragma appears in a @fa<generic_formal_part>, then the @fa<direct_name> shall denote a type declared in the same @fa<generic_formal_part> as the pragma, and be one for which the Preelaborable_Initialization aspect can be directly specified as True.
@xindent<@s9<NOTES@hr 4 Pragmas Elaborate and Elaborate_All, which do not have associated aspects, are found in 10.2.1.>>

Questions? Ask the ACAA Technical Agent