Question

Suppose I would like to match for the following pipe-delimited strings:

std::string re("a|*|c");
std::string x("a|b|c");
std::string y("a|c|d");

does_match( re, x );  // want to return TRUE
does_match( re, y );  // want to return FALSE

what is the best way to implement does_match() using boost::regex?

I think I may be running into issues with escaping pipes and stars. Note that I don’t care about the actual matches: I just want an easy-to-use interface to does_match() to tell me if I have a match.

In particular, I hope to get this working without having to use a ton of escapes for pipes and stars. I don’t care about other more general uses of regex – if I can use pipe-delimiters and * for wildcards, that’s sufficient.

Maybe I should do a transform inside does_match to make boost::regex happy? Or perhaps my entire approach is bad (like I should be using some kind of strsplit() instead?).

Answer 1

Ok, I think I’m barking up the wrong tree by attempting to solve this with boost::regex() – boost::split() is probably more appropriate.

#include <string>
#include <vector>

#include <boost/algorithm/string.hpp>

bool does_match( const std::string& fmt, const std::string& str )
{
    std::vector<std::string> strs, fmts;
    boost::split( strs, str, boost::is_any_of( "|" ));
    boost::split( fmts, fmt, boost::is_any_of( "|" ));
    if ( strs.size()!=fmts.size() )
        return false;
    size_t n = strs.size(); 
    for( size_t i=0; i<n; ++i )
        if ( fmts[i].compare("*")  && fmts[i].compare( strs[i] ))
            return false;
    return true;
}