- Declarations sometimes come in two parts. A declaration that requires a
second part is said to require completion. The second part is called the
completion of the declaration (and of the entity declared), and is either
another declaration, a body, or a pragma.
Name Resolution Rules
- A construct that can be a completion is interpreted as the completion of
a prior declaration only if:
- The declaration and the completion occur immediately within the
same declarative region;
- The defining name or defining_program_unit_name in the completion
is the same as in the declaration, or in the case of a pragma,
the pragma applies to the declaration;
- If the declaration is overloadable, then the completion either
has a type-conformant profile, or is a pragma.
- An implicit declaration shall not have a completion. For any explicit
declaration that is specified to require completion, there shall be a
corresponding explicit completion.
- At most one completion is allowed for a given declaration. Additional
requirements on completions appear where each kind of completion is defined.
- A type is completely defined at a place that is after its full type definition
(if it has one) and after all of its subcomponent types are completely defined.
A type shall be completely defined before it is frozen (see
13.14 and 7.3).
(88) Completions are in principle allowed for any kind of explicit
declaration. However, for some kinds of declaration, the only allowed
completion is a pragma Import, and implementations are not required to
support pragma Import for every kind of entity.
(89) There are rules that prevent premature uses of declarations that have
a corresponding completion. The Elaboration_Checks of 3.11
prevent such uses at run time for subprograms, protected operations, tasks,
and generic units. The rules of 13.14, ``Freezing
Rules'' prevent, at compile time, premature uses of other entities such
as private types and deferred constants.
-- Email comments, additions, corrections, gripes, kudos, etc. to:
Magnus Kempe -- Magnus.Kempe@di.epfl.ch
Page last generated: 95-03-12