spirit/example/fundamental/regular_expression.cpp

///////////////////////////////////////////////////////////////////////////////
//
//  Demonstrate regular expression parser objects
//
//  This sample requires an installed version of the boost regex library
//  (http://www.boost.org) The sample was tested with boost V1.28.0
//
///////////////////////////////////////////////////////////////////////////////
#include <string>
#include <iostream>

#include <boost/spirit/core.hpp>

///////////////////////////////////////////////////////////////////////////////
//
//  The following header must be included, if regular expression support is
//  required for Spirit.
//
//  The BOOST_SPIRIT_NO_REGEX_LIB PP constant should be defined, if you're using the
//  Boost.Regex library from one translation unit only. Otherwise you have to
//  link with the Boost.Regex library as defined in the related documentation
//  (see. http://www.boost.org).
//
///////////////////////////////////////////////////////////////////////////////
#define BOOST_SPIRIT_NO_REGEX_LIB
#include <boost/spirit/utility/regex.hpp>

///////////////////////////////////////////////////////////////////////////////
//  used namespaces
using namespace std;
using namespace boost::spirit;

///////////////////////////////////////////////////////////////////////////////
// main entry point
int main (int argc, char *argv[])
{
    const char *ptest = "123 E 456";
    const char *prx = "[1-9]+[[:space:]]*E[[:space:]]*";

    cout << "Parse " << ptest << " against regular expression: " << prx
        << endl;

    // 1. direct use of rxlit<>
    rxstrlit<> regexpr(prx);
    parse_info<> result;
    string str;

    result = parse (ptest, regexpr[assign(str)]);
    if (result.hit)
    {
        cout << "Parsed regular expression successfully!" << endl;
        cout << "Matched (" << (int)result.length << ") characters: ";
        cout << "\"" << str << "\"" << endl;
    }
    else
    {
        cout << "Failed to parse regular expression!" << endl;
    }
    cout << endl;

    // 2. use of regex_p predefined parser object
    result = parse (ptest, regex_p(prx)[assign(str)]);
    if (result.hit)
    {
        cout << "Parsed regular expression successfully!" << endl;
        cout << "Matched (" << (int)result.length << ") characters: ";
        cout << "\"" << str << "\"" << endl;
    }
    else
    {
        cout << "Failed to parse regular expression!" << endl;
    }
    cout << endl;

    return 0;
}