4.1 Names
1
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.
Syntax
2
name ::=
direct_name |
explicit_dereference
|
indexed_component |
slice
|
selected_component |
attribute_reference
|
type_conversion |
function_call
|
character_literal
3
direct_name ::= identifier |
operator_symbol
4
prefix ::= name |
implicit_dereference
5
explicit_dereference ::= name.
all
6
implicit_dereference ::= name
7
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
8
The
name
in a
dereference (either an
implicit_dereference
or an
explicit_dereference) is expected to
be of any access type.
Static Semantics
9
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.
10
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.
Dynamic Semantics
11/2
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
character_literal.
12
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.
13
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
name.
Examples
14
Examples of direct
names:
15
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)
16
Examples of dereferences:
17
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
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