libs/spirit/example/qi/sum.cpp
/*=============================================================================
Copyright (c) 2002-2010 Joel de Guzman
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
=============================================================================*/
///////////////////////////////////////////////////////////////////////////////
//
// A parser for summing a comma-separated list of numbers using phoenix.
//
// [ JDG June 28, 2002 ] spirit1
// [ JDG March 24, 2007 ] spirit2
//
///////////////////////////////////////////////////////////////////////////////
#include <boost/config/warning_disable.hpp>
//[tutorial_adder_includes
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix_core.hpp>
#include <boost/spirit/include/phoenix_operator.hpp>
#include <iostream>
#include <string>
//]
namespace client
{
//[tutorial_adder_using
namespace qi = boost::spirit::qi;
namespace ascii = boost::spirit::ascii;
namespace phoenix = boost::phoenix;
using qi::double_;
using qi::_1;
using ascii::space;
using phoenix::ref;
//]
///////////////////////////////////////////////////////////////////////////
// Our adder
///////////////////////////////////////////////////////////////////////////
//[tutorial_adder
template <typename Iterator>
bool adder(Iterator first, Iterator last, double& n)
{
bool r = qi::phrase_parse(first, last,
// Begin grammar
(
double_[ref(n) = _1] >> *(',' >> double_[ref(n) += _1])
)
,
// End grammar
space);
if (first != last) // fail if we did not get a full match
return false;
return r;
}
//]
}
////////////////////////////////////////////////////////////////////////////
// Main program
////////////////////////////////////////////////////////////////////////////
int
main()
{
std::cout << "/////////////////////////////////////////////////////////\n\n";
std::cout << "\t\tA parser for summing a list of numbers...\n\n";
std::cout << "/////////////////////////////////////////////////////////\n\n";
std::cout << "Give me a comma separated list of numbers.\n";
std::cout << "The numbers are added using Phoenix.\n";
std::cout << "Type [q or Q] to quit\n\n";
std::string str;
while (getline(std::cin, str))
{
if (str.empty() || str[0] == 'q' || str[0] == 'Q')
break;
double n;
if (client::adder(str.begin(), str.end(), n))
{
std::cout << "-------------------------\n";
std::cout << "Parsing succeeded\n";
std::cout << str << " Parses OK: " << std::endl;
std::cout << "sum = " << n;
std::cout << "\n-------------------------\n";
}
else
{
std::cout << "-------------------------\n";
std::cout << "Parsing failed\n";
std::cout << "-------------------------\n";
}
}
std::cout << "Bye... :-) \n\n";
return 0;
}