From Jason Turner

[re.traits]

C++11 → C++14 5.5 KB 96 lines
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Archived: C++11 | C++14
Markdown: C++11 | C++14
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  1. tmp/tmp3q_l_nxh/{from.md → to.md} +73 -19
tmp/tmp3q_l_nxh/{from.md → to.md} RENAMED
@@ -109,38 +109,71 @@ classification named by the character sequence designated by the
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  iterator range \[`first`, `last`). If the parameter `icase` is true then
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  the returned mask identifies the character classification without regard
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  to the case of the characters being matched, otherwise it does honor the
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  case of the characters being matched.[^1] The value returned shall be
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  independent of the case of the characters in the character sequence. If
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- the name is not recognized then returns a value that compares equal to
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- 0.
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- *Remarks:* For `regex_traits<char>`, at least the names `"d"`, `"w"`,
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- `"s"`, `"alnum"`, `"alpha"`, `"blank"`, `"cntrl"`, `"digit"`, `"graph"`,
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- `"lower"`, `"print"`, `"punct"`, `"space"`, `"upper"` and `"xdigit"`
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- shall be recognized. For `regex_traits<wchar_t>`, at least the names
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- `L"d"`, `L"w"`, `L"s"`, `L"alnum"`, `L"alpha"`, `L"blank"`, `L"cntrl"`,
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- `L"digit"`, `L"graph"`, `L"lower"`, `L"print"`, `L"punct"`, `L"space"`,
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- `L"upper"` and `L"xdigit"` shall be recognized.
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  ``` cpp
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  bool isctype(charT c, char_class_type f) const;
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  ```
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  *Effects:* Determines if the character `c` is a member of the character
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  classification represented by `f`.
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- *Returns:* Converts `f` into a value `m` of type `std::ctype_base::mask`
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- in an unspecified manner, and returns `true` if
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- `use_facet<ctype<charT> >(getloc()).is(m, c)` is `true`. Otherwise
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- returns `true` if `f` bitwise or’ed with the result of calling
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- `lookup_classname` with an iterator pair that designates the character
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- sequence `"w"` is not equal to 0 and `c == ’_’`, or if `f` bitwise or’ed
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- with the result of calling `lookup_classname` with an iterator pair that
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- designates the character sequence `"blank"` is not equal to 0 and `c` is
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- one of an *implementation-defined* subset of the characters for which
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- `isspace(c, getloc())` returns `true`, otherwise returns `false`.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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  ``` cpp
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  int value(charT ch, int radix) const;
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  ```
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@@ -170,5 +203,26 @@ locale_type getloc()const;
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  *Returns:* if no locale has been imbued then a copy of the global locale
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  in effect at the time of construction of `*this`, otherwise a copy of
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  the last argument passed to `imbue`.
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  iterator range \[`first`, `last`). If the parameter `icase` is true then
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  the returned mask identifies the character classification without regard
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  to the case of the characters being matched, otherwise it does honor the
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  case of the characters being matched.[^1] The value returned shall be
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  independent of the case of the characters in the character sequence. If
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+ the name is not recognized then returns `char_class_type()`.
 
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+ *Remarks:* For `regex_traits<char>`, at least the narrow character names
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+ in Table  [[tab:re.traits.classnames]] shall be recognized. For
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+ `regex_traits<wchar_t>`, at least the wide character names in
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+ Table  [[tab:re.traits.classnames]] shall be recognized.
 
 
 
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  ``` cpp
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  bool isctype(charT c, char_class_type f) const;
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  ```
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  *Effects:* Determines if the character `c` is a member of the character
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  classification represented by `f`.
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+ *Returns:* Given the following function prototype:
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+
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+ ``` cpp
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+ // for exposition only
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+ template<class C>
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+ ctype_base::mask convert(typename regex_traits<C>::char_class_type f);
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+ ```
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+
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+ that returns a value in which each `ctype_base::mask` value
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+ corresponding to a value in `f` named in
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+ Table  [[tab:re.traits.classnames]] is set, then the result is
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+ determined as if by:
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+
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+ ``` cpp
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+ ctype_base::mask m = convert<charT>(f);
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+ const ctype<charT>& ct = use_facet<ctype<charT>>(getloc());
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+ if (ct.is(m, c)) {
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+ return true;
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+ } else if (c == ct.widen('_')) {
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+ charT w[1] = { ct.widen('w') };
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+ char_class_type x = lookup_classname(w, w+1);
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+
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+ return (f&x) == x;
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+ } else {
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+ return false;
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+ }
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+ ```
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+
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+ ``` cpp
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+ regex_traits<char> t;
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+ string d("d");
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+ string u("upper");
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+ regex_traits<char>::char_class_type f;
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+ f = t.lookup_classname(d.begin(), d.end());
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+ f |= t.lookup_classname(u.begin(), u.end());
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+ ctype_base::mask m = convert<char>(f); // m == ctype_base::digit|ctype_base::upper
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+ ```
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+
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+ ``` cpp
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+ regex_traits<char> t;
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+ string w("w");
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+ regex_traits<char>::char_class_type f;
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+ f = t.lookup_classname(w.begin(), w.end());
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+ t.isctype('A', f); // returns true
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+ t.isctype('_', f); // returns true
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+ t.isctype(' ', f); // returns false
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+ ```
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  ``` cpp
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  int value(charT ch, int radix) const;
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  ```
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  *Returns:* if no locale has been imbued then a copy of the global locale
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  in effect at the time of construction of `*this`, otherwise a copy of
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  the last argument passed to `imbue`.
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+ **Table: Character class names and corresponding `ctype` masks** <a id="tab:re.traits.classnames">[tab:re.traits.classnames]</a>
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+
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+ | Narrow character name | Wide character name | Corresponding `ctype_base::mask` value |
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+ | --------------------- | ------------------- | -------------------------------------- |
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+ | `"alnum"` | `L"alnum"` | `ctype_base::alnum` |
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+ | `"alpha"` | `L"alpha"` | `ctype_base::alpha` |
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+ | `"blank"` | `L"blank"` | `ctype_base::blank` |
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+ | `"cntrl"` | `L"cntrl"` | `ctype_base::cntrl` |
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+ | `"digit"` | `L"digit"` | `ctype_base::digit` |
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+ | `"d"` | `L"d"` | `ctype_base::digit` |
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+ | `"graph"` | `L"graph"` | `ctype_base::graph` |
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+ | `"lower"` | `L"lower"` | `ctype_base::lower` |
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+ | `"print"` | `L"print"` | `ctype_base::print` |
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+ | `"punct"` | `L"punct"` | `ctype_base::punct` |
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+ | `"space"` | `L"space"` | `ctype_base::space` |
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+ | `"s"` | `L"s"` | `ctype_base::space` |
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+ | `"upper"` | `L"upper"` | `ctype_base::upper` |
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+ | `"w"` | `L"w"` | `ctype_base::alnum` |
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+ | `"xdigit"` | `L"xdigit"` | `ctype_base::xdigit` |
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+
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+