正则表达式误解或只是破坏执行？ [英] Regular Expressions misunderstanding or just broken implementation?

问题描述

我尝试了一个非常简单的使用 regex_search ，不明白为什么我没有得到匹配：

唉，gcc-C ++ 0x-实现4.5似乎不工作，我得到一个链接错误这里

但这里是我的gcc-4.7.0尝试，很简单：

  #include< iostream> 
 #include< string> 
 #include< regex> 
 using namespace std; 
 int main（）{
 regex rxWorld（world）; 
 const string text =hello world！; 
 const auto t0 = text.cbegin（）; 
 smatch match; 
 const bool ok = regex_search（text，match，rxWorld）; 
 / * ... * / 
} 
  

ok == true 和在匹配我把例子简化为一个非常简单的正则表达式。

但是通过在 / * ... * / 上打印代码，

  cout< text：'<< text 
<< 'ok：<< ok 
<< size：< match.size（）; 
 cout<< pos：< match.position（）
<< len：< match.length（）; 
 for（const auto& sub：match）{
 cout<< [<<（sub.first-t0）<...<<（sub.second-t0）
< ：<< sub.matched 
<< '<<< sub.str（）
<< ']; 
} 
 cout<< endl; 
  

输出为：

  $ ./regex-search-01.x 
 text：'hello world！'ok：0 size：0 pos：-1 len：0 
  regex_search（t0，text.cend（），match，rxWorld）
 code>和 const char * text ，无变化。 
`
 
 
 
 我是否理解 regex_search 错了？我完全感到困惑。 
解决方案
正如你可以从 C ++  -  0xlbstdc ++的状态正则表达式支持不完整。 
特别是match_results没有完成。 
 
 
 
欢迎志愿者;  - ）
 
 
 
  [As of gcc- 4.9]  2 将获得完全支持。
 
I tried a very simple use of regex_search and can not understand why I do not get a match:

Alas, the gcc-C++0x-implementations 4.5 does not seem to be working, I get a link error here.

But here is my gcc-4.7.0 try, quite straightforward:
#include <iostream>
#include <string>
#include <regex>
using namespace std;
int main () {
    regex rxWorld("world");
    const string text = "hello world!";
    const auto t0 = text.cbegin();
    smatch match;
    const bool ok = regex_search(text, match, rxWorld);
    /* ... */
}
I think I should get ok==true and something in match as well. I reduced the example to a very simple regex for this. I tried slightly more complicated first.

But by printing code at /* ... */ says otherwise:
  cout << "  text:'" << text
       << "' ok:" << ok
       << " size:" << match.size();
  cout << " pos:" << match.position()
       << " len:"<< match.length();
  for(const auto& sub : match) {
      cout << " ["<<(sub.first-t0)<<".."<<(sub.second-t0)
           << ":"<<sub.matched
           << "'"<<sub.str()
           << "']";
  }
  cout << endl;
The output is:
$ ./regex-search-01.x
text:'hello world!' ok:0 size:0 pos:-1 len:0
Update: I also tried regex_search(t0, text.cend(), match, rxWorld) and const char* text, no change.
`

Is my understanding of regex_search wrong? I am completely baffled. Or is it just the gcc?
解决方案
As you can see from the C++-0x status of libstdc++ the regex support is incomplete.
In particular match_results are not finished.  Iterators are not even started.

Volunteers are welcome ;-)

[EDIT] [As of gcc-4.9]2  will be fully supported.

                        
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