H.4.1 Aspect No_Controlled_Parts
Static Semantics
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.
Aspect Description
for No_Controlled_Parts: A
specification that a type and its descendants do not have controlled
parts.
Discussion: {
AI12-0407-1}
Since this is a Boolean-valued aspect, the blanket
restrictions defined by 13.1.1 apply to
the specification of Boolean-valued aspects on descendants of types with
such aspects. But we still need rules about inheritance from progenitors
and about hiding the aspect; it would be too painful to repeat those
rules here (and have future maintenance fixes not get applied to this
aspect).
Legality Rules
{
AI12-0256-1}
{
AI12-0407-1}
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.Discussion: {
AI12-0407-1}
This check breaks privacy by looking at the full
definition of all of the types involved. This is more like a representation
aspect than an operational aspect, but representation aspects are not
allowed on partial views and we need this aspect to be visible to clients.
{
AI12-0256-1}
{
AI12-0407-1}
When enforcing the above rule within a generic
body G or within the body of a generic unit declared within the
declarative region of generic unit G, a generic formal private
type of G and a generic formal derived type of G whose
ancestor is a tagged type whose No_Controlled_Parts aspect is False are
considered to have a controlled part.Reason: This is
a typical generic assume-the-worst rule.
To be honest: {
AI12-0407-1}
If the ancestor of the generic derived type is
class-wide, the aspect in question belongs to the specific type associated
with the class-wide type.
Extensions to Ada 2012
Ada 2005 and 2012 Editions sponsored in part by Ada-Europe
