| /*============================================================================= |
| 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 Calculator example demonstrating the grammar and semantic actions |
| // using plain functions. The parser prints code suitable for a stack |
| // based virtual machine. |
| // |
| // [ JDG May 10, 2002 ] spirit1 |
| // [ JDG March 4, 2007 ] spirit2 |
| // |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| #include <boost/config/warning_disable.hpp> |
| #include <boost/spirit/include/qi.hpp> |
| |
| #include <iostream> |
| #include <string> |
| |
| namespace client |
| { |
| namespace qi = boost::spirit::qi; |
| namespace ascii = boost::spirit::ascii; |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Semantic actions |
| /////////////////////////////////////////////////////////////////////////////// |
| namespace |
| { |
| void do_int(int n) { std::cout << "push " << n << std::endl; } |
| void do_add() { std::cout << "add\n"; } |
| void do_subt() { std::cout << "subtract\n"; } |
| void do_mult() { std::cout << "mult\n"; } |
| void do_div() { std::cout << "divide\n"; } |
| void do_neg() { std::cout << "negate\n"; } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Our calculator grammar |
| /////////////////////////////////////////////////////////////////////////////// |
| template <typename Iterator> |
| struct calculator : qi::grammar<Iterator, ascii::space_type> |
| { |
| calculator() : calculator::base_type(expression) |
| { |
| using qi::uint_; |
| |
| expression = |
| term |
| >> *( ('+' >> term [&do_add]) |
| | ('-' >> term [&do_subt]) |
| ) |
| ; |
| |
| term = |
| factor |
| >> *( ('*' >> factor [&do_mult]) |
| | ('/' >> factor [&do_div]) |
| ) |
| ; |
| |
| factor = |
| uint_ [&do_int] |
| | '(' >> expression >> ')' |
| | ('-' >> factor [&do_neg]) |
| | ('+' >> factor) |
| ; |
| } |
| |
| qi::rule<Iterator, ascii::space_type> expression, term, factor; |
| }; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Main program |
| /////////////////////////////////////////////////////////////////////////////// |
| int |
| main() |
| { |
| std::cout << "/////////////////////////////////////////////////////////\n\n"; |
| std::cout << "Expression parser...\n\n"; |
| std::cout << "/////////////////////////////////////////////////////////\n\n"; |
| std::cout << "Type an expression...or [q or Q] to quit\n\n"; |
| |
| using boost::spirit::ascii::space; |
| typedef std::string::const_iterator iterator_type; |
| typedef client::calculator<iterator_type> calculator; |
| |
| calculator calc; // Our grammar |
| |
| std::string str; |
| while (std::getline(std::cin, str)) |
| { |
| if (str.empty() || str[0] == 'q' || str[0] == 'Q') |
| break; |
| |
| std::string::const_iterator iter = str.begin(); |
| std::string::const_iterator end = str.end(); |
| bool r = phrase_parse(iter, end, calc, space); |
| |
| if (r && iter == end) |
| { |
| std::cout << "-------------------------\n"; |
| std::cout << "Parsing succeeded\n"; |
| std::cout << "-------------------------\n"; |
| } |
| else |
| { |
| std::string rest(iter, end); |
| std::cout << "-------------------------\n"; |
| std::cout << "Parsing failed\n"; |
| std::cout << "stopped at: \": " << rest << "\"\n"; |
| std::cout << "-------------------------\n"; |
| } |
| } |
| |
| std::cout << "Bye... :-) \n\n"; |
| return 0; |
| } |
| |
| |