Struct template null_regex_traits

boost::xpressive::null_regex_traits — stub regex_traits for non-char data

Synopsis

template<typename Elem> 
struct null_regex_traits {
  // types
  typedef Elem                       char_type;      
  typedef std::vector< char_type >   string_type;    
  typedef unspecified                locale_type;    
  typedef int                        char_class_type;
  typedef regex_traits_version_1_tag version_tag;    

  // construct/copy/destruct
  null_regex_traits(locale_type = locale_type());

  // public member functions
  bool operator==(null_regex_traits< char_type > const &) const;
  bool operator!=(null_regex_traits< char_type > const &) const;
  char_type widen(char) const;

  // public static functions
  static unsigned char hash(char_type) ;
  static char_type translate(char_type) ;
  static char_type translate_nocase(char_type) ;
  static bool in_range(char_type, char_type, char_type) ;
  static bool in_range_nocase(char_type, char_type, char_type) ;
  template<typename FwdIter> static string_type transform(FwdIter, FwdIter) ;
  template<typename FwdIter> 
    static string_type transform_primary(FwdIter, FwdIter) ;
  template<typename FwdIter> 
    static string_type lookup_collatename(FwdIter, FwdIter) ;
  template<typename FwdIter> 
    static char_class_type lookup_classname(FwdIter, FwdIter, bool) ;
  static bool isctype(char_type, char_class_type) ;
  static int value(char_type, int) ;
  static locale_type imbue(locale_type) ;
  static locale_type getloc() ;
};

Description

`null_regex_traits` public construct/copy/destruct

null_regex_traits(locale_type = locale_type());

Initialize a null_regex_traits object.

`null_regex_traits` public member functions

bool operator==(null_regex_traits< char_type > const & that) const;

Checks two null_regex_traits objects for equality

Returns:

true.

bool operator!=(null_regex_traits< char_type > const & that) const;

Checks two null_regex_traits objects for inequality

Returns:

false.

```
char_type widen(char ch) const;
```
Convert a char to a Elem

Parameters:

ch

The source character.

Returns:

Elem(ch).

`null_regex_traits` public static functions

```
static unsigned char hash(char_type ch) ;
```
Returns a hash value for a Elem 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 char_type translate_nocase(char_type ch) ;

No-op

Parameters:

`ch`	The source character.

Returns:

```
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.

static bool in_range_nocase(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.

Notes:

Since the null_regex_traits does not do case-folding, this function is equivalent to in_range().

```
template<typename FwdIter> 
  static string_type transform(FwdIter begin, FwdIter end) ;
```
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).

Notes:

Not used in xpressive 1.0
```
template<typename FwdIter> 
  static string_type transform_primary(FwdIter begin, FwdIter end) ;
```
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).

Notes:

Not used in xpressive 1.0
```
template<typename FwdIter> 
  static string_type lookup_collatename(FwdIter begin, FwdIter end) ;
```
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.

Notes:

Not used in xpressive 1.0
```
template<typename FwdIter> 
  static char_class_type 
  lookup_classname(FwdIter begin, FwdIter end, bool icase) ;
```
The null_regex_traits does not have character classifications, so lookup_classname() is unused.

Parameters:

begin

not used

end

not used

icase

not used

Returns:

static_cast<char_class_type>(0)
```
static bool isctype(char_type ch, char_class_type mask) ;
```
The null_regex_traits does not have character classifications, so isctype() is unused.

Parameters:

ch

not used

mask

not used

Returns:

false
```
static int value(char_type ch, int radix) ;
```
The null_regex_traits recognizes no elements as digits, so value() is unused.

Parameters:

ch

not used

radix

not used

Returns:

-1

static locale_type imbue(locale_type loc) ;

Not used

Parameters:

loc

not used

Returns:

loc

```
static locale_type getloc() ;
```
Returns locale_type().

Returns:

locale_type()

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