std::regex_traits - Man Page

typedef _RegexMask char_class_type
typedef _Ch_type char_type
typedef std::locale locale_type
typedef std::basic_string< char_type > string_type

regex_traits ()
Constructs a default traits object.
locale_type getloc () const
Gets a copy of the current locale in use by the regex_traits object.
locale_type imbue (locale_type __loc)
Imbues the regex_traits object with a copy of a new locale.
bool isctype (_Ch_type __c, char_class_type __f) const
Determines if c is a member of an identified class.
template<typename _Fwd_iter > char_class_type lookup_classname (_Fwd_iter __first, _Fwd_iter __last, bool __icase=false) const
Maps one or more characters to a named character classification.
template<typename _Fwd_iter > string_type lookup_collatename (_Fwd_iter __first, _Fwd_iter __last) const
Gets a collation element by name.
template<typename _Fwd_iter > string_type transform (_Fwd_iter __first, _Fwd_iter __last) const
Gets a sort key for a character sequence.
template<typename _Fwd_iter > string_type transform_primary (_Fwd_iter __first, _Fwd_iter __last) const
Gets a sort key for a character sequence, independent of case.
char_type translate (char_type __c) const
Performs the identity translation.
char_type translate_nocase (char_type __c) const
Translates a character into a case-insensitive equivalent.
int value (_Ch_type __ch, int __radix) const
Converts a digit to an int.

static std::size_t length (const char_type *__p)
Gives the length of a C-style string starting at __p.

locale_type _M_locale

class std::regex_traits< typename >"Describes aspects of a regular expression.

A regular expression traits class that satisfies the requirements of section [28.7].

The class regex is parameterized around a set of related types and functions used to complete the definition of its semantics. This class satisfies the requirements of such a traits class.

Since

C++11

Constructs a default traits object.

Gets a copy of the current locale in use by the regex_traits object.

Referenced by std::regex_traits< _CharType >::isctype().

Imbues the regex_traits object with a copy of a new locale.

Parameters

Returns

a copy of the previous locale in use by the regex_traits object.

Note

Calling imbue with a different locale than the one currently in use invalidates all cached data held by *this.

Determines if c is a member of an identified class.

Parameters

Returns

true if the character __c is a member of the classification represented by __f, false otherwise.

Exceptions

std::bad_cast if the current locale does not have a ctype facet.

References std::use_facet().

Gives the length of a C-style string starting at __p.

Parameters

Returns

the number of characters between *__p and the first default-initialized value of type char_type. In other words, uses the C-string algorithm for determining the length of a sequence of characters.

References std::basic_string< _CharT, _Traits, _Alloc >::length().

Maps one or more characters to a named character classification.

Parameters

Returns

an unspecified value that represents the character classification named by the character sequence designated by the iterator range [__first, __last). If icase is true, the returned mask identifies the classification regardless of the case of the characters to be matched (for example, [[:lower:]] is the same as [[:alpha:]]), otherwise a case-dependent classification is returned. The value returned shall be independent of the case of the characters in the character sequence. If the name is not recognized then returns a value that compares equal to 0.

At least the following names (or their wide-character equivalent) are supported.

• d
• w
• s
• alnum
• alpha
• blank
• cntrl
• digit
• graph
• lower
• print
• punct
• space
• upper
• xdigit

References std::use_facet().

Gets a collation element by name.

Parameters

Returns

a sequence of one or more characters that represents the collating element consisting of the character sequence designated by the iterator range [__first, __last). Returns an empty string if the character sequence is not a valid collating element.

References std::use_facet().

Gets a sort key for a character sequence.

Parameters

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).

What this really does is provide a more efficient way to compare a string to multiple other strings in locales with fancy collation rules and equivalence classes.

Returns

a locale-specific sort key equivalent to the input range.

Exceptions

std::bad_cast if the current locale does not have a collate facet.

References std::basic_string< _CharT, _Traits, _Alloc >::data(), std::basic_string< _CharT, _Traits, _Alloc >::size(), and std::use_facet().

Referenced by std::regex_traits< typename >::transform_primary().

Gets a sort key for a character sequence, independent of case.

Parameters

Effects: if typeid(use_facet<collate<_Ch_type> >) == typeid(collate_byname<_Ch_type>) and the form of the sort key returned by collate_byname<_Ch_type>::transform(__first, __last) is known and can be converted into a primary sort key then returns that key, otherwise returns an empty string.

Todo

Implement this function correctly.

References std::regex_traits< typename >::transform(), and std::use_facet().

Performs the identity translation.

Parameters

Returns

Translates a character into a case-insensitive equivalent.

Parameters

Returns

the locale-specific lower-case equivalent of __c.

Exceptions

std::bad_cast if the imbued locale does not support the ctype facet.

References std::use_facet().

Converts a digit to an int.

Parameters

Returns

the value represented by the digit __ch in base radix if the character __ch is a valid digit in base radix; otherwise returns -1.

References std::basic_ios< _CharT, _Traits >::fail(), std::hex(), and std::oct().