C++ named requirements: RegexTraits

 

C++

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Named requirements

Language support library

Concepts library (C++20)

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Technical Specifications

 

C++ named requirements

Basic
DefaultConstructible CopyAssignable CopyConstructible	MoveAssignable (C++11) MoveConstructible (C++11) Destructible
Layout
TrivialType (C++11) TriviallyCopyable (C++11)	StandardLayoutType (C++11) PODType
Library-Wide
EqualityComparable LessThanComparable Swappable (C++11) ValueSwappable (C++11) NullablePointer (C++11) Hash (C++11)	Allocator FunctionObject Callable Predicate BinaryPredicate Compare
Container
Container SequenceContainer ContiguousContainer (C++17) ReversibleContainer	AssociativeContainer AllocatorAwareContainer UnorderedAssociativeContainer (C++11)
Container Elements
DefaultInsertable (C++11) CopyInsertable (C++11) MoveInsertable (C++11)	EmplaceConstructible (C++11) Erasable (C++11)
Iterator
LegacyIterator LegacyOutputIterator LegacyInputIterator LegacyForwardIterator	LegacyBidirectionalIterator LegacyRandomAccessIterator LegacyContiguousIterator (C++17) ConstexprIterator (C++20)
Stream I/O
FormattedInputFunction UnformattedInputFunction	FormattedOutputFunction UnformattedOutputFunction
Random Numbers
SeedSequence (C++11) RandomNumberEngine (C++11)	RandomNumberDistribution (C++11) UniformRandomBitGenerator (C++11) RandomNumberEngineAdaptor (C++11)
Concurrency
BasicLockable (C++11) Lockable (C++11) TimedLockable (C++11)	Mutex (C++11) TimedMutex (C++11) SharedMutex (C++17) SharedTimedMutex (C++14)
Other
CharTraits RegexTraits (C++11) BitmaskType NumericType LiteralType (C++11)	UnaryTypeTrait (C++11) BinaryTypeTrait (C++11) TransformationTrait (C++11) Clock (C++11) TrivialClock (C++11)

 

RegexTraits is a traits class that abstracts operations needed for a given character type when as template type parameters for std::basic_regex.

Requirements

Given

• CharT, a character type
• X, a RegexTraits type for type CharT
• u, an object of type X
• v, an object of type const X
• p, a value of type const CharT*
• I1, I2, input iterators
• F1, F2, forward iterators
• c, a value of type const CharT
• s, an object of type X::string_type
• cs, an object of type const X::string_type
• b, a value of type bool
• I, a value of type int
• cl, an object of type X::char_class_type
• loc, an object of type X::locale_type

expression	return type	semantics
X::char_type	CharT	Used to refer to the character type.
X::string_type	std::basic_string<CharT>
X::locale_type		A CopyConstructible type that represents the locale used by the traits class.
X::char_class_type		A BitmaskType type that represents a particular character classification.
X::length(p)	std::size_t	Returns: the smallest i such that p[i] == 0. Complexity is linear in i.
v.translate(c)	X::char_type	Returns: a character such that for any character d considered to be equivalent to c, then v.translate(c) == v.translate(d).
v.translate_nocase(c)	X::char_type	Returns: a character such that for any character C considered to be equivalent to c without regard to case, then v.translate_nocase(c) == v.translate_nocase(C).
v.transform(F1, F2)	X::string_type	Returns: a sort key for the character sequence designated by the iterator range [F1, F2) such that if the character sequence [G1, G2) sorts before the character sequence [H1, H2), then v.transform(G1, G2) < v.transform(H1, H2).
v.transform_primary(F1, F2)	X::string_type	Returns: a sort key for the character sequence designated by the iterator range [F1, F2) such that if the character sequence [G1, G2) sorts before the character sequence [H1, H2) without regard to case, then v.transform_primary(G1, G2) < v.transform_primary(H1, H2).
v.lookup_collatename(F1, F2)	X::string_type	Returns: An empty string if the character sequence is not a valid collating element A sequence of characters that represents the collating element consisting of the character sequence designated by the iterator range [F1, F2) otherwise
v.lookup_classname(F1, F2, b)	X::char_class_type	Converts the character sequence designated by the iterator range [F1, F2) into a value of a BitmaskType that can subsequently be passed to isctype Values returned from lookup_classname can be bitwise or'ed together; the resulting value represents membership in either of the corresponding character classes If b is true, the returned bitmask is suitable for matching characters without regard to their case. Returns ​0​ if the character sequence is not the name of a character class recognized by X. The value returned shall be independent of the case of the characters in the sequence.
v.isctype(c, cl)	bool	Returns: whether c is a member of one of the character classes designated by cl or not.
v.value(c, I)	int	Returns: The value represented by the digit c in base I if the character c is a valid digit in base I -1 otherwise
u.imbue(loc)	X::locale_type	Imbues u with the locale loc Returns: The previous locale used by u if any
v.getloc()	X::locale_type	Returns: The previous locale used by v if any.

Standard library

RegexTraits is satisfied by the following standard library classes:

template<> class regex_traits<char>; template<> class regex_traits<wchar_t>;		(since C++11) (since C++11)