CVS difference for ai12s/ai12-0190-1.txt

--- ai12s/ai12-0190-1.txt	2016/12/28 04:20:39	1.5
+++ ai12s/ai12-0190-1.txt	2018/03/02 03:17:49	1.6
@@ -1,4 +1,4 @@
-!standard 5.5.2(2/3)                                  16-10-12  AI12-0190-1/03
+!standard 5.5.2(2/3)                                  18-02-28  AI12-0190-1/04
 !class Amendment 16-06-02
 !status work item 16-06-02
 !status received 16-05-06
@@ -8,7 +8,10 @@
 !summary
 
 Provide an ability to construct a local anonymous function at the point
-of a call on a subprogram that has an access-to-function parameter.
+of a call on a subprogram that has an access-to-function parameter,
+or in an instantiation with a formal subprogram parameter, or other
+contexts where the expected type is an access-to-function type,
+or there is an expected profile for a function.
 
 !problem
 
@@ -53,7 +56,63 @@
 
 !wording
 
-** TBD.
+Replace 4.4(7/3) with:
+
+  primary ::= 
+     numeric_literal | null | string_literal | aggregate
+   | name | allocator | (expression)
+   | (conditional_expression) | (quantified_expression)
+   | function_expression
+   
+Add section after 4.5.8:
+
+  4.5.9 Function Expressions
+
+  Function expressions provide a way to define a function at a point
+  where an access-to-function type is the expected type, or in a generic
+  instantiation as an actual parameter corresponding to a formal subprogram
+  parameter.
+  
+              Syntax
+              
+    function_expression ::=
+      (FUNCTION [function_formal_parameter_list] RETURN expression)
+
+    function_formal_parameter_list ::=
+      formal_part | (identifier {, identifier})
+
+             Name Resolution
+             
+  In a context where there is an expected type rather than an expected
+  profile for a function_expression, the expected type shall be a single
+  access-to-function type, and the profile of this type is considered
+  the expected profile for the function_expression.  The result type of
+  the expected profile of the function_expression is the expected type
+  for the expression of the function_expression. If there is no
+  function_formal_parameter_list, the expected profile shall have no
+  parameters.  If the function_formal_parameter_list is a formal_part,
+  then it shall be subtype conformant to the expected profile if there
+  is an expected type, or merely mode conformant otherwise.  If the
+  function_formal_parameter_list is a sequence of identifiers, the
+  number of identifiers in the sequence shall be the same as the number
+  of formal parameters in the expected profile.
+  
+           Static Semantics
+
+  A function_expression used in a context where there is an expected
+  type is equivalent to a local expression_function_declaration (see
+  6.8), with the function_expression replaced by an Access
+  attribute_reference of this locally defined function; otherwise, the
+  function_expression is equivalent to such a local declaration with the
+  function_expression replaced by a name denoting this locally defined
+  function.  The profile of this locally defined function has a result
+  type determined by the expected profile, and a formal part determined
+  by the formal_part, if provided in the expression_function, or by the
+  formal part of the expected profile otherwise, but with the name of
+  each formal parameter of the expected profile replaced by the
+  corresponding identifier in the sequence of identifiers.  The expression
+  of this locally defined expression function is that of the
+  function_expression. 
 
 !discussion
 
@@ -1742,5 +1801,13 @@
 and if anybody wants a name for the lambda:
 
 function ParisMatch(X : String) return Boolean is Filter("Paris");
+
+****************************************************************
+
+From: Tucker Taft
+Sent: Tuesday, February 27, 2018  6:32 PM
+
+I have added wording to this AI on "function expressions". [This is version
+/04 of the AI - ED.]
 
 ****************************************************************