| /*============================================================================= |
| Copyright (c) 2002-2003 Joel de Guzman |
| Copyright (c) 2002 Juan Carlos Arevalo-Baeza |
| 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) |
| =============================================================================*/ |
| #include <boost/spirit/include/classic_core.hpp> |
| #include <boost/spirit/include/classic_functor_parser.hpp> |
| #include <boost/spirit/include/classic_assign_actor.hpp> |
| #include <iostream> |
| #include <vector> |
| #include <string> |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // |
| // Demonstrates the functor_parser. This is discussed in the |
| // "Functor Parser" chapter in the Spirit User's Guide. |
| // |
| /////////////////////////////////////////////////////////////////////////////// |
| using namespace std; |
| using namespace BOOST_SPIRIT_CLASSIC_NS; |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // |
| // Our parser functor |
| // |
| /////////////////////////////////////////////////////////////////////////////// |
| struct number_parser |
| { |
| typedef int result_t; |
| template <typename ScannerT> |
| int |
| operator()(ScannerT const& scan, result_t& result) const |
| { |
| if (scan.at_end()) |
| return -1; |
| |
| char ch = *scan; |
| if (ch < '0' || ch > '9') |
| return -1; |
| |
| result = 0; |
| int len = 0; |
| |
| do |
| { |
| result = result*10 + int(ch - '0'); |
| ++len; |
| ++scan; |
| } while (!scan.at_end() && (ch = *scan, ch >= '0' && ch <= '9')); |
| |
| return len; |
| } |
| }; |
| |
| functor_parser<number_parser> number_parser_p; |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // |
| // Our number parser functions |
| // |
| /////////////////////////////////////////////////////////////////////////////// |
| bool |
| parse_number(char const* str, int& n) |
| { |
| return parse(str, lexeme_d[number_parser_p[assign_a(n)]], space_p).full; |
| } |
| |
| bool |
| parse_numbers(char const* str, std::vector<int>& n) |
| { |
| return |
| parse( |
| str, |
| lexeme_d[number_parser_p[push_back_a(n)]] |
| >> *(',' >> lexeme_d[number_parser_p[push_back_a(n)]]), |
| space_p |
| ).full; |
| } |
| |
| //////////////////////////////////////////////////////////////////////////// |
| // |
| // Main program |
| // |
| //////////////////////////////////////////////////////////////////////////// |
| int |
| main() |
| { |
| cout << "/////////////////////////////////////////////////////////\n\n"; |
| cout << "\t\tA number parser implemented as a functor for Spirit...\n\n"; |
| cout << "/////////////////////////////////////////////////////////\n\n"; |
| |
| cout << "Give me an integer number command\n"; |
| cout << "Commands:\n"; |
| cout << " A <num> --> parses a single number\n"; |
| cout << " B <num>, <num>, ... --> parses a series of numbers "; |
| cout << "separated by commas\n"; |
| cout << " Q --> quit\n\n"; |
| |
| string str; |
| while (getline(cin, str)) |
| { |
| if (str.empty() || str[0] == 'q' || str[0] == 'Q') |
| break; |
| |
| else if (str[0] == 'a' || str[0] == 'A') |
| { |
| int n; |
| if (parse_number(str.c_str()+1, n)) |
| { |
| cout << "-------------------------\n"; |
| cout << "Parsing succeeded\n"; |
| cout << str << " Parses OK: " << n << endl; |
| cout << "-------------------------\n"; |
| } |
| else |
| { |
| cout << "-------------------------\n"; |
| cout << "Parsing failed\n"; |
| cout << "-------------------------\n"; |
| } |
| } |
| |
| else if (str[0] == 'b' || str[0] == 'B') |
| { |
| std::vector<int> n; |
| if (parse_numbers(str.c_str()+1, n)) |
| { |
| cout << "-------------------------\n"; |
| cout << "Parsing succeeded\n"; |
| int size = n.size(); |
| cout << str << " Parses OK: " << size << " number(s): " << n[0]; |
| for (int i = 1; i < size; ++i) { |
| cout << ", " << n[i]; |
| } |
| cout << endl; |
| cout << "-------------------------\n"; |
| } |
| else |
| { |
| cout << "-------------------------\n"; |
| cout << "Parsing failed\n"; |
| cout << "-------------------------\n"; |
| } |
| } |
| |
| else |
| { |
| cout << "-------------------------\n"; |
| cout << "Unrecognized command!!"; |
| cout << "-------------------------\n"; |
| } |
| } |
| |
| cout << "Bye... :-) \n\n"; |
| return 0; |
| } |