| /*============================================================================= |
| Copyright (c) 2002-2003 Joel de Guzman |
| http://spirit.sourceforge.net/ |
| |
| Use, modification and distribution is subject to 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 list of numbers. Demonstrating phoenix |
| // This is discussed in the "Phoenix" chapter in the Spirit User's Guide. |
| // |
| // [ JDG 6/28/2002 ] |
| // |
| /////////////////////////////////////////////////////////////////////////////// |
| #include <boost/spirit/include/classic_core.hpp> |
| #include <boost/spirit/include/phoenix1_primitives.hpp> |
| #include <boost/spirit/include/phoenix1_operators.hpp> |
| #include <iostream> |
| #include <string> |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| using namespace std; |
| using namespace BOOST_SPIRIT_CLASSIC_NS; |
| using namespace phoenix; |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // |
| // Our adder |
| // |
| /////////////////////////////////////////////////////////////////////////////// |
| template <typename IteratorT> |
| bool adder(IteratorT first, IteratorT last, double& n) |
| { |
| return parse(first, last, |
| |
| // Begin grammar |
| ( |
| real_p[var(n) = arg1] >> *(',' >> real_p[var(n) += arg1]) |
| ) |
| , |
| // End grammar |
| |
| space_p).full; |
| } |
| |
| //////////////////////////////////////////////////////////////////////////// |
| // |
| // Main program |
| // |
| //////////////////////////////////////////////////////////////////////////// |
| int |
| main() |
| { |
| cout << "/////////////////////////////////////////////////////////\n\n"; |
| cout << "\t\tA parser for summing a list of numbers...\n\n"; |
| cout << "/////////////////////////////////////////////////////////\n\n"; |
| |
| cout << "Give me a comma separated list of numbers.\n"; |
| cout << "The numbers are added using Phoenix.\n"; |
| cout << "Type [q or Q] to quit\n\n"; |
| |
| string str; |
| while (getline(cin, str)) |
| { |
| if (str.empty() || str[0] == 'q' || str[0] == 'Q') |
| break; |
| |
| double n; |
| if (adder(str.begin(), str.end(), n)) |
| { |
| cout << "-------------------------\n"; |
| cout << "Parsing succeeded\n"; |
| cout << str << " Parses OK: " << endl; |
| |
| cout << "sum = " << n; |
| cout << "\n-------------------------\n"; |
| } |
| else |
| { |
| cout << "-------------------------\n"; |
| cout << "Parsing failed\n"; |
| cout << "-------------------------\n"; |
| } |
| } |
| |
| cout << "Bye... :-) \n\n"; |
| return 0; |
| } |
| |
| |