C++ named requirements: RegexTraits (since C++11)

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C++ named requirements

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)
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