Expression  | Return type  | Assertion/note pre-/post-condition   | 
X::char_type  | charT  | The character container type used in the implementation of class
    template basic_regex.  | 
X::string_type  | basic_string<charT>  | |
X::locale_type  | A copy constructible type  | A type that represents the locale used by the traits class.   | 
X::char_class_type  | A bitmask type ([bitmask.types]).  | A bitmask type representing a particular character classification.      | 
X::length(p)  | size_t  |   Complexity is
    linear in i .  | 
v.translate(c)  | X::char_type  | Returns a character such that for any character d that is to
    be considered equivalent to c then v.translate(c) == v.translate(d).      | 
v.translate_nocase(c)  | X::char_type  | For all characters C that are to be considered equivalent
    to c when comparisons are to be performed 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)
  when character case is not considered
  then v.transform_primary(G1, G2) < v.transform_primary(H1, H2).      | 
v.lookup_collatename(F1, F2)  | X::string_type  | Returns a sequence of characters that represents the collating element
    consisting of the character sequence designated by the iterator range
  [F1, F2).  Returns an empty string if the character sequence is not
  a valid collating element.      | 
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 bitmask type 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.   The value returned shall be independent of the case of
    the characters in the sequence.      | 
v.isctype(c, cl)  | bool  | Returns true if character c is a member of
    one of the character classes designated by cl,
    false otherwise.      | 
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;
  otherwise returns -1.    | 
u.imbue(loc)  | X::locale_type  | |
v.getloc()  | X::locale_type  | Returns the current locale used by v, if any.   |