[Boost-users] regular expression help

From: llwaeva_at_[hidden]
Date: 2006-07-27 12:47:39

Hi there,
  I am going to retrieve the following pattern %K{xxx} where xxx can be
anything except line break. I find and modify  the following code from
document, is that right for my case?

 boost::regex expK("[^%]*%K{([^\r\n])}");  
std::string::const_iterator start, end; 
start = sourcesrc.begin(); 
end = sourcesrc.end(); 
boost::match_results<std::string::const_iterator> what; 
boost::match_flag_type flags = boost::match_default; 

 while ( regex_search(start, end, what, expK, flags) ) 
{      
   // handle the match string, i.e. xxx     
   my_fun( std::string( what[1].first, what[1].second ) );     
   start = what[1].second;      
   flags |= boost::match_prev_avail;       
  flags |= boost::match_not_bob;   
 }

Here, expK found all the substring matching %K{xxx} (not including double % case). But the program didn't give
me what I want, I guess the problem is from the expression where { and } is not expressed correctly. However, I
didn't  found how to express { and } in the document. Here is my guess of the correct form, tell me if it is
correct or not

1) boost::regex expK("[^%]*%K\{([^\r\n])\}");   // here \{ represents { and \} represents } 
2) boost::regex expK("[^%]*%K[{]{1}([^\r\n])[}]{1}");   // use [{]{1} and [}]{1} to limit the { and } occur once exactly
3) boost::regex expK("[^%]*%K\\{([^\r\n])\\}");   // here \\{ represents { and \\} represents } 

which one is correct? or all is wrong? 

Please help!

Thanks in advance.