// Copyright (c) 2001-2010 Hartmut Kaiser // Copyright (c) 2001-2010 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 complex number micro generator - take 2. Look'ma no semantic actions! // // [ HK July 26, 2009 ] spirit2 // /////////////////////////////////////////////////////////////////////////////// #include #include #include #include #include #include #include #include #include namespace client { /////////////////////////////////////////////////////////////////////////// // Our complex number parser/compiler (that's just a copy of the complex // number example from Qi (see examples/qi/complex_number.cpp) /////////////////////////////////////////////////////////////////////////// template bool parse_complex(Iterator first, Iterator last, std::complex& c) { using boost::spirit::qi::double_; using boost::spirit::qi::_1; using boost::spirit::qi::phrase_parse; using boost::spirit::ascii::space; using boost::phoenix::ref; double rN = 0.0; double iN = 0.0; bool r = phrase_parse(first, last, ( '(' >> double_[ref(rN) = _1] >> -(',' >> double_[ref(iN) = _1]) >> ')' | double_[ref(rN) = _1] ), space); if (!r || first != last) // fail if we did not get a full match return false; c = std::complex(rN, iN); return r; } /////////////////////////////////////////////////////////////////////////// // Our complex number generator /////////////////////////////////////////////////////////////////////////// //[tutorial_karma_complex_number_easier template bool generate_complex(OutputIterator sink, std::complex const& c) { using boost::spirit::karma::double_; using boost::spirit::karma::omit; using boost::spirit::karma::generate; return generate(sink, // Begin grammar ( !double_(0.0) << '(' << double_ << ", " << double_ << ')' | omit[double_] << double_ << omit[double_] ), // End grammar c.imag(), c.real(), c.imag() // Data to output ); } //] } /////////////////////////////////////////////////////////////////////////////// // Main program /////////////////////////////////////////////////////////////////////////////// int main() { std::cout << "/////////////////////////////////////////////////////////\n\n"; std::cout << "\t\tA complex number micro generator for Spirit...\n\n"; std::cout << "/////////////////////////////////////////////////////////\n\n"; std::cout << "Give me a complex number of the form r or (r) or (r,i) \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; std::complex c; if (client::parse_complex(str.begin(), str.end(), c)) { std::cout << "-------------------------\n"; std::string generated; std::back_insert_iterator sink(generated); if (!client::generate_complex(sink, c)) { std::cout << "-------------------------\n"; std::cout << "Generating failed\n"; std::cout << "-------------------------\n"; } else { std::cout << "-------------------------\n"; std::cout << "Generated: " << generated << "\n"; std::cout << "-------------------------\n"; } } else { std::cout << "-------------------------\n"; std::cout << "Parsing failed\n"; std::cout << "-------------------------\n"; } } std::cout << "Bye... :-) \n\n"; return 0; }