/*============================================================================= 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 #include #include #include #include /////////////////////////////////////////////////////////////////////////////// using namespace std; using namespace BOOST_SPIRIT_CLASSIC_NS; using namespace phoenix; /////////////////////////////////////////////////////////////////////////////// // // Our adder // /////////////////////////////////////////////////////////////////////////////// template 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; }