A.4.10 String Comparison
Static Semantics
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function Ada.Strings.Equal_Case_Insensitive (Left, Right : String)
return Boolean
with Pure;
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Returns True if the strings consist of the same sequence of characters
after applying
locale-independent simple
case folding, as defined by
Section 3.13 of Unicode
Version 15.0 documents referenced in Clause
2 of ISO/IEC 10646:2020. Otherwise, returns False. This function
uses the same method as is used to determine whether two identifiers
are the same.
Discussion: {
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For String, this is equivalent to converting to lower case and comparing.
Not so for other string types. For Wide_Strings and Wide_Wide_Strings,
note that this result is a more accurate comparison than converting the
strings to lower case and comparing the results; it is possible that
the lower case conversions are the same but this routine will report
the strings as different
and vice versa.
Additionally, Unicode says that the result of this function will never
change for strings
in Normalization Form KC
made up solely of defined code points; there is no such guarantee for
case conversion to lower case.
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The “documents referenced” means Unicode,
Chapter 4 (specifically, section 4.2 — Case). See the Implementation
Notes in
2.3 for a source for machine-readable
definitions of these properties.
with Ada.Strings.Equal_Case_Insensitive;
function Ada.Strings.Fixed.Equal_Case_Insensitive
(Left, Right : String)
return Boolean
renames Ada.Strings.Equal_Case_Insensitive;
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generic
with package Bounded
is
new Ada.Strings.Bounded.Generic_Bounded_Length (<>);
function Ada.Strings.Bounded.Equal_Case_Insensitive
(Left, Right : Bounded.Bounded_String)
return Boolean
with Preelaborate, Nonblocking, Global =>
in out synchronized;
Equivalent to Strings.Equal_Case_Insensitive
(Bounded.To_String (Left), Bounded.To_String (Right));
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function Ada.Strings.Unbounded.Equal_Case_Insensitive
(Left, Right : Unbounded_String)
return Boolean
with Preelaborate, Nonblocking, Global =>
in out synchronized;
Equivalent to Strings.Equal_Case_Insensitive
(To_String (Left), To_String (Right));
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function Ada.Strings.Less_Case_Insensitive (Left, Right : String)
return Boolean
with Pure;
Performs a lexicographic
comparison of strings Left and Right, converted to lower case.
with Ada.Strings.Less_Case_Insensitive;
function Ada.Strings.Fixed.Less_Case_Insensitive
(Left, Right : String)
return Boolean
renames Ada.Strings.Less_Case_Insensitive;
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generic
with package Bounded
is
new Ada.Strings.Bounded.Generic_Bounded_Length (<>);
function Ada.Strings.Bounded.Less_Case_Insensitive
(Left, Right : Bounded.Bounded_String)
return Boolean
with Preelaborate, Nonblocking, Global =>
in out synchronized;
Equivalent to Strings.Less_Case_Insensitive
(Bounded.To_String (Left), Bounded.To_String (Right));
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function Ada.Strings.Unbounded.Less_Case_Insensitive
(Left, Right : Unbounded_String)
return Boolean
with Preelaborate, Nonblocking, Global =>
in out synchronized;
Equivalent to Strings.Less_Case_Insensitive
(To_String (Left), To_String (Right));
Extensions to Ada 2005
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The Strings.Equal_Case_Insensitive, Strings.Fixed.Equal_Case_Insensitive,
Strings.Bounded.Equal_Case_Insensitive, Strings.Unbounded.Equal_Case_Insensitive,
Strings.Less_Case_Insensitive, Strings.Fixed.Less_Case_Insensitive, Strings.Bounded.Less_Case_Insensitive,
Strings.Unbounded.Less_Case_Insensitive functions are new.
Wording Changes from Ada 2022
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Corrigendum: Updated the wording to directly
reference Unicode rather than the previously indirect references. This
should not change any behavior.
Ada 2005 and 2012 Editions sponsored in part by Ada-Europe
