A.4.7 Wide_String Handling
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Facilities for handling strings of Wide_Character elements are found
in the packages Strings.Wide_Maps, Strings.Wide_Fixed, Strings.Wide_Bounded,
Strings.Wide_Unbounded, and Strings.Wide_Maps.Wide_Constants, and in
the library functions Strings.Wide_Hash, Strings.Wide_Fixed.Wide_Hash,
Strings.Wide_Bounded.Wide_Hash, Strings.Wide_Unbounded.Wide_Hash, Strings.Wide_Hash_Case_Insensitive,
Strings.Wide_Fixed.Wide_Hash_Case_Insensitive, Strings.Wide_Bounded.Wide_Hash_Case_Insensitive,
Strings.Wide_Unbounded.Wide_Hash_Case_Insensitive, Strings.Wide_Equal_Case_Insensitive,
Strings.Wide_Fixed.Wide_Equal_Case_Insensitive, Strings.Wide_Bounded.Wide_Equal_Case_Insensitive,
and Strings.Wide_Unbounded.Wide_Equal_Case_Insensitive. They provide
the same string-handling operations as the corresponding packages and
functions for strings of Character elements.
Static Semantics
The package Strings.Wide_Maps has the following declaration.
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package Ada.Strings.Wide_Maps
with Preelaborate, Nonblocking, Global =>
in out synchronized is{
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--
Representation for a set of Wide_Character values:
type Wide_Character_Set
is private
with Preelaborable_Initialization;
Null_Set :
constant Wide_Character_Set;
type Wide_Character_Range
is
record
Low : Wide_Character;
High : Wide_Character;
end record;
--
Represents Wide_Character range Low..High
type Wide_Character_Ranges
is array (Positive
range <>)
of Wide_Character_Range;
function To_Set (Ranges :
in Wide_Character_Ranges)
return Wide_Character_Set;
function To_Set (Span :
in Wide_Character_Range)
return Wide_Character_Set;
function To_Ranges (Set :
in Wide_Character_Set)
return Wide_Character_Ranges;
function "=" (Left, Right : in Wide_Character_Set) return Boolean;
function "not" (Right : in Wide_Character_Set)
return Wide_Character_Set;
function "and" (Left, Right : in Wide_Character_Set)
return Wide_Character_Set;
function "or" (Left, Right : in Wide_Character_Set)
return Wide_Character_Set;
function "xor" (Left, Right : in Wide_Character_Set)
return Wide_Character_Set;
function "-" (Left, Right : in Wide_Character_Set)
return Wide_Character_Set;
function Is_In (Element :
in Wide_Character;
Set :
in Wide_Character_Set)
return Boolean;
function Is_Subset (Elements :
in Wide_Character_Set;
Set :
in Wide_Character_Set)
return Boolean;
function "<=" (Left : in Wide_Character_Set;
Right : in Wide_Character_Set)
return Boolean renames Is_Subset;
--
Alternative representation for a set of Wide_Character values:
subtype Wide_Character_Sequence
is Wide_String;
function To_Set (Sequence :
in Wide_Character_Sequence)
return Wide_Character_Set;
function To_Set (Singleton :
in Wide_Character)
return Wide_Character_Set;
function To_Sequence (Set :
in Wide_Character_Set)
return Wide_Character_Sequence;
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--
Representation for a Wide_Character to Wide_Character mapping:
type Wide_Character_Mapping
is private
with Preelaborable_Initialization;
function Value (Map :
in Wide_Character_Mapping;
Element :
in Wide_Character)
return Wide_Character;
Identity :
constant Wide_Character_Mapping;
function To_Mapping (From, To :
in Wide_Character_Sequence)
return Wide_Character_Mapping;
function To_Domain (Map :
in Wide_Character_Mapping)
return Wide_Character_Sequence;
function To_Range (Map :
in Wide_Character_Mapping)
return Wide_Character_Sequence;
type Wide_Character_Mapping_Function
is
access function (From :
in Wide_Character)
return Wide_Character;
private
... -- not specified by the language
end Ada.Strings.Wide_Maps;
The context clause for each of the packages Strings.Wide_Fixed,
Strings.Wide_Bounded, and Strings.Wide_Unbounded identifies Strings.Wide_Maps
instead of Strings.Maps.
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Types Wide_Character_Set and Wide_Character_Mapping need finalization.
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For each of the packages Strings.Fixed, Strings.Bounded, Strings.Unbounded,
and Strings.Maps.Constants, and for library functions Strings.Hash, Strings.Fixed.Hash,
Strings.Bounded.Hash, Strings.Unbounded.Hash, Strings.Hash_Case_Insensitive,
Strings.Fixed.Hash_Case_Insensitive, Strings.Bounded.Hash_Case_Insensitive,
Strings.Unbounded.Hash_Case_Insensitive, Strings.Equal_Case_Insensitive,
Strings.Fixed.Equal_Case_Insensitive, Strings.Bounded.Equal_Case_Insensitive,
and Strings.Unbounded.Equal_Case_Insensitive, the corresponding wide
string package or function has the same contents except that
Wide_Space replaces Space
Wide_Character replaces Character
Wide_String replaces String
Wide_Character_Set replaces Character_Set
Wide_Character_Mapping replaces Character_Mapping
Wide_Character_Mapping_Function replaces Character_Mapping_Function
Wide_Maps replaces Maps
Bounded_Wide_String replaces Bounded_String
Null_Bounded_Wide_String replaces Null_Bounded_String
To_Bounded_Wide_String replaces To_Bounded_String
To_Wide_String replaces To_String
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Set_Bounded_Wide_String replaces Set_Bounded_String
Unbounded_Wide_String replaces Unbounded_String
Null_Unbounded_Wide_String replaces Null_Unbounded_String
Wide_String_Access replaces String_Access
To_Unbounded_Wide_String replaces To_Unbounded_String
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Set_Unbounded_Wide_String replaces Set_Unbounded_String
The following additional
declaration is present in Strings.Wide_Maps.Wide_Constants:
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Character_Set :
constant Wide_Maps.Wide_Character_Set;
--
Contains each Wide_Character value WC such that
--
Characters.Conversions.Is_Character(WC) is True {
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Each Wide_Character_Set constant in the package Strings.Wide_Maps.Wide_Constants
contains no values outside the Character portion of Wide_Character. Similarly,
each Wide_Character_Mapping constant in this package is the identity
mapping when applied to any element outside the Character portion of
Wide_Character.
NOTE If a null Wide_Character_Mapping_Function
is passed to any of the Wide_String handling subprograms, Constraint_Error
is propagated.
Incompatibilities With Ada 95
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Various new operations are added to Strings.Wide_Fixed,
Strings.Wide_Bounded, and Strings.Wide_Unbounded. If one of these packages
is referenced in a
use_clause,
and an entity
E with the same
defining_identifier
as a new entity is defined in a package that is also referenced in a
use_clause,
the entity
E may no longer be use-visible, resulting in errors.
This should be rare and is easily fixed if it does occur.
Extensions to Ada 95
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Amendment Correction: Added
pragma
Preelaborable_Initialization to types Wide_Character_Set and Wide_Character_Mapping,
so that they can be used to declare default-initialized objects in preelaborated
units.
Wording Changes from Ada 95
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Added wide versions of Strings.Hash and Strings.Unbounded.Hash.
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Added wording so that Strings.Wide_Maps.Wide_Constants does not change
to Pure.
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The second Note is now normative text, since there is no way to derive
it from the other rules. It's a little weird given the use of Unicode
character classifications in Ada 2005; but changing it would be inconsistent
with Ada 95 and a one-to-one mapping isn't necessarily correct anyway.
Extensions to Ada 2005
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The case insenstive library functions (Strings.Wide_Equal_Case_Insensitive,
Strings.Wide_Fixed.Wide_Equal_Case_Insensitive, Strings.Wide_Bounded.Wide_Equal_Case_Insensitive,
Strings.Wide_Unbounded.Wide_Equal_Case_Insensitive, Strings.Wide_Hash_Case_Insensitive,
Strings.Wide_Fixed.Wide_Hash_Case_Insensitive, Strings.Wide_Bounded.Wide_Hash_Case_Insensitive,
and Strings.Wide_Unbounded.Wide_Hash_Case_Insensitive) are new.
Wording Changes from Ada 2005
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Correction: Identified Wide_Character_Set and Wide_Character_Mapping
as needing finalization. It is likely that they are implemented with
a controlled type, so this change is unlikely to make any difference
in practice.
Ada 2005 and 2012 Editions sponsored in part by Ada-Europe
