| /*============================================================================= |
| Copyright (c) 2001-2003 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 complex number micro parser (using subrules) |
| // |
| // [ JDG 5/10/2002 ] |
| // |
| /////////////////////////////////////////////////////////////////////////////// |
| #include <boost/spirit/include/classic_core.hpp> |
| #include <iostream> |
| #include <complex> |
| #include <string> |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| using namespace std; |
| using namespace BOOST_SPIRIT_CLASSIC_NS; |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // |
| // Our complex number micro parser |
| // |
| /////////////////////////////////////////////////////////////////////////////// |
| bool |
| parse_complex(char const* str, complex<double>& c) |
| { |
| double rN = 0.0; |
| double iN = 0.0; |
| |
| subrule<0> first; |
| subrule<1> r; |
| subrule<2> i; |
| |
| if (parse(str, |
| |
| // Begin grammar |
| ( |
| first = '(' >> r >> !(',' >> i) >> ')' | r, |
| r = real_p[assign(rN)], |
| i = real_p[assign(iN)] |
| ) |
| , |
| // End grammar |
| |
| space_p).full) |
| { |
| c = complex<double>(rN, iN); |
| return true; |
| } |
| else |
| { |
| return false; |
| } |
| } |
| |
| //////////////////////////////////////////////////////////////////////////// |
| // |
| // Main program |
| // |
| //////////////////////////////////////////////////////////////////////////// |
| int |
| main() |
| { |
| cout << "/////////////////////////////////////////////////////////\n\n"; |
| cout << "\t\tA complex number micro parser for Spirit...\n\n"; |
| cout << "/////////////////////////////////////////////////////////\n\n"; |
| |
| cout << "Give me a complex number of the form r or (r) or (r,i) \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; |
| |
| complex<double> c; |
| if (parse_complex(str.c_str(), c)) |
| { |
| cout << "-------------------------\n"; |
| cout << "Parsing succeeded\n"; |
| cout << str << " Parses OK: " << c << endl; |
| cout << "-------------------------\n"; |
| } |
| else |
| { |
| cout << "-------------------------\n"; |
| cout << "Parsing failed\n"; |
| cout << "-------------------------\n"; |
| } |
| } |
| |
| cout << "Bye... :-) \n\n"; |
| return 0; |
| } |
| |
| |