- Names can denote declared entities, whether declared explicitly or
implicitly (see 3.1). Names can also denote objects or subprograms
designated by access values; the results of type_conversions or function_calls; subcomponents and slices of objects and values; protected subprograms,
single entries, entry families, and entries in families of entries. Finally,
names can denote attributes of any of the foregoing.
direct_name | explicit_dereference
| indexed_component | slice
| selected_component | attribute_reference
| type_conversion | function_call
direct_name ::= identifier | operator_symbol
prefix ::= name | implicit_dereference
explicit_dereference ::= name.all
implicit_dereference ::= name
- Certain forms of name (indexed_components, selected_components, slices,
and attributes) include a prefix that is either itself a name that denotes
some related entity, or an implicit_dereference of an access value that
designates some related entity.
Name Resolution Rules
- The name in a dereference (either an implicit_dereference or an explicit_dereference) is expected to be of any access type.
- If the type of the name in a dereference is some access-to-object type T,
then the dereference denotes a view of an object, the nominal subtype of the
view being the designated subtype of T.
- If the type of the name in a dereference is some access-to-subprogram
type S, then the dereference denotes a view of a subprogram, the profile of
the view being the designated profile of S.
- The evaluation of a name determines the entity denoted by the name.
This evaluation has no other effect for a name that is a direct_name or a
- The evaluation of a name that has a prefix includes the evaluation of
the prefix. The evaluation of a prefix consists of the evaluation of the
name or the implicit_dereference. The prefix denotes the entity denoted by
the name or the implicit_dereference.
- The evaluation of a dereference consists of the evaluation of the name
and the determination of the object or subprogram that is designated by the
value of the name. A check is made that the value of the name is not the
null access value. Constraint_Error is raised if this check fails. The
dereference denotes the object or subprogram designated by the value of the
- Examples of direct names:
Pi -- the direct name of a number (see 3.3.2)
Limit -- the direct name of a constant (see 3.3.1)
Count -- the direct name of a scalar variable (see 3.3.1)
Board -- the direct name of an array variable (see 3.6.1)
Matrix -- the direct name of a type (see 3.6)
Random -- the direct name of a function (see 6.1)
Error -- the direct name of an exception (see 11.1)
- Examples of dereferences:
Next_Car.all -- explicit dereference denoting the object designated by
-- the access variable Next_Car (see 3.10.1)
Next_Car.Owner -- selected component with implicit dereference;
-- same as Next_Car.all.Owner
- Indexed Components
- Selected Components
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Page last generated: 95-03-12