Struct template cpp_regex_traits

boost::xpressive::cpp_regex_traits — Encapsaulates a std::locale for use by the basic_regex<> class template.

Synopsis

// In header: <boost/xpressive/traits/cpp_regex_traits.hpp>

template<typename Char> 
struct cpp_regex_traits {
  // types
  typedef Char                           char_type;      
  typedef std::basic_string< char_type > string_type;    
  typedef std::locale                    locale_type;    
  typedef unspecified                    char_class_type;
  typedef regex_traits_version_2_tag     version_tag;    
  typedef unspecified                    base_type;      

  // construct/copy/destruct
  cpp_regex_traits(locale_type const & = locale_type());

  // public member functions
  bool operator==(cpp_regex_traits< char_type > const &) const;
  bool operator!=(cpp_regex_traits< char_type > const &) const;
  char_type widen(char) const;
  char_type translate_nocase(char_type) const;
  char_type tolower(char_type) const;
  char_type toupper(char_type) const;
  string_type fold_case(char_type) const;
  bool in_range_nocase(char_type, char_type, char_type) const;
  template<typename FwdIter> 
    string_type transform_primary(FwdIter, FwdIter) const;
  template<typename FwdIter> 
    string_type lookup_collatename(FwdIter, FwdIter) const;
  template<typename FwdIter> 
    char_class_type lookup_classname(FwdIter, FwdIter, bool) const;
  bool isctype(char_type, char_class_type) const;
  int value(char_type, int) const;
  locale_type imbue(locale_type);
  locale_type getloc() const;
  unsigned char hash(unsigned char);
  unsigned char hash(char);
  unsigned char hash(signed char);
  unsigned char hash(wchar_t);

  // public static functions
  static unsigned char hash(char_type);
  static char_type translate(char_type);
  static bool in_range(char_type, char_type, char_type);
};

Description

`cpp_regex_traits` public construct/copy/destruct

```
cpp_regex_traits(locale_type const & loc = locale_type());
```
Initialize a cpp_regex_traits object to use the specified std::locale, or the global std::locale if none is specified.

`cpp_regex_traits` public member functions

```
bool operator==(cpp_regex_traits< char_type > const & that) const;
```
Checks two cpp_regex_traits objects for equality

Returns:

this->getloc() == that.getloc().
```
bool operator!=(cpp_regex_traits< char_type > const & that) const;
```
Checks two cpp_regex_traits objects for inequality

Returns:

this->getloc() != that.getloc().
```
char_type widen(char ch) const;
```
Convert a char to a Char

Parameters:

ch

The source character.

Returns:

std::use_facet<std::ctype<char_type> >(this->getloc()).widen(ch).
```
char_type translate_nocase(char_type ch) const;
```
Converts a character to lower-case using the internally-stored std::locale.

Parameters:

ch

The source character.

Returns:

std::tolower(ch, this->getloc()).
```
char_type tolower(char_type ch) const;
```
Converts a character to lower-case using the internally-stored std::locale.

Parameters:

ch

The source character.

Returns:

std::tolower(ch, this->getloc()).
```
char_type toupper(char_type ch) const;
```
Converts a character to upper-case using the internally-stored std::locale.

Parameters:

ch

The source character.

Returns:

std::toupper(ch, this->getloc()).
```
string_type fold_case(char_type ch) const;
```
Returns a string_type containing all the characters that compare equal disregrarding case to the one passed in. This function can only be called if has_fold_case<cpp_regex_traits<Char> >value is true.

Parameters:

ch

The source character.

Returns:

string_type containing all chars which are equal to ch when disregarding case

bool in_range_nocase(char_type first, char_type last, char_type ch) const;

Checks to see if a character is within a character range, irregardless of case.

	Note
	The default implementation doesn't do proper Unicode case folding, but this is the best we can do with the standard ctype facet.

Parameters:

`ch`	The source character.
`first`	The bottom of the range, inclusive.
`last`	The top of the range, inclusive.

Returns:

in_range(first, last, ch) || in_range(first, last, tolower(ch, this->getloc())) || in_range(first, last, toupper(ch, this->getloc()))

```
template<typename FwdIter> 
  string_type transform_primary(FwdIter, FwdIter) const;
```
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).

Note

Not currently used
```
template<typename FwdIter> 
  string_type lookup_collatename(FwdIter, FwdIter) const;
```
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.

Note

Not currently used

template<typename FwdIter> 
  char_class_type 
  lookup_classname(FwdIter begin, FwdIter end, bool icase) const;

For the character class name represented by the specified character sequence, return the corresponding bitmask representation.

Parameters:

`begin`	A forward iterator to the start of the character sequence representing the name of the character class.
`end`	The end of the character sequence.
`icase`	Specifies whether the returned bitmask should represent the case-insensitive version of the character class.

Returns:

A bitmask representing the character class.

bool isctype(char_type ch, char_class_type mask) const;

Tests a character against a character class bitmask.

Parameters:

`ch`	The character to test.
`mask`	The character class bitmask against which to test.

Requires:

mask is a bitmask returned by lookup_classname, or is several such masks bit-or'ed together.

Returns:

true if the character is a member of any of the specified character classes, false otherwise.

int value(char_type ch, int radix) const;

Convert a digit character into the integer it represents.

Parameters:

`ch`	The digit character.
`radix`	The radix to use for the conversion.

Requires:

radix is one of 8, 10, or 16.

Returns:

-1 if ch is not a digit character, the integer value of the character otherwise. The conversion is performed by imbueing a std::stringstream with this->getloc(); setting the radix to one of oct, hex or dec; inserting ch into the stream; and extracting an int.

```
locale_type imbue(locale_type loc);
```
Imbues *this with loc

Parameters:

loc

A std::locale.

Returns:

the previous std::locale used by *this.
```
locale_type getloc() const;
```
Returns the current std::locale used by *this.
```
unsigned char hash(unsigned char ch);
```
```
unsigned char hash(char ch);
```
```
unsigned char hash(signed char ch);
```
```
unsigned char hash(wchar_t ch);
```

`cpp_regex_traits` public static functions

```
static unsigned char hash(char_type ch);
```
Returns a hash value for a Char in the range [0, UCHAR_MAX]

Parameters:

ch

The source character.

Returns:

a value between 0 and UCHAR_MAX, inclusive.
```
static char_type translate(char_type ch);
```
No-op

Parameters:

ch

The source character.

Returns:

ch
```
static bool in_range(char_type first, char_type last, char_type ch);
```
Checks to see if a character is within a character range.

Parameters:

ch

The source character.

first

The bottom of the range, inclusive.

last

The top of the range, inclusive.

Returns:

first <= ch && ch <= last.

	Note
	Not currently used

	Note
	Not currently used

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