123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188 |
- /*=============================================================================
- 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 Roman Numerals Parser (demonstrating the symbol table). This is
- // discussed in the "Symbols" chapter in the Spirit User's Guide.
- //
- // [ JDG August 22, 2002 ] spirit1
- // [ JDG March 13, 2007 ] spirit2
- //
- ///////////////////////////////////////////////////////////////////////////////
- #include <boost/config/warning_disable.hpp>
- #include <boost/spirit/include/qi.hpp>
- #include <boost/spirit/include/phoenix_operator.hpp>
- #include <iostream>
- #include <string>
- namespace client
- {
- namespace qi = boost::spirit::qi;
- namespace ascii = boost::spirit::ascii;
- ///////////////////////////////////////////////////////////////////////////////
- // Parse roman hundreds (100..900) numerals using the symbol table.
- // Notice that the data associated with each slot is the parser's attribute
- // (which is passed to attached semantic actions).
- ///////////////////////////////////////////////////////////////////////////////
- //[tutorial_roman_hundreds
- struct hundreds_ : qi::symbols<char, unsigned>
- {
- hundreds_()
- {
- add
- ("C" , 100)
- ("CC" , 200)
- ("CCC" , 300)
- ("CD" , 400)
- ("D" , 500)
- ("DC" , 600)
- ("DCC" , 700)
- ("DCCC" , 800)
- ("CM" , 900)
- ;
- }
- } hundreds;
- //]
- ///////////////////////////////////////////////////////////////////////////////
- // Parse roman tens (10..90) numerals using the symbol table.
- ///////////////////////////////////////////////////////////////////////////////
- //[tutorial_roman_tens
- struct tens_ : qi::symbols<char, unsigned>
- {
- tens_()
- {
- add
- ("X" , 10)
- ("XX" , 20)
- ("XXX" , 30)
- ("XL" , 40)
- ("L" , 50)
- ("LX" , 60)
- ("LXX" , 70)
- ("LXXX" , 80)
- ("XC" , 90)
- ;
- }
- } tens;
- //]
- ///////////////////////////////////////////////////////////////////////////////
- // Parse roman ones (1..9) numerals using the symbol table.
- ///////////////////////////////////////////////////////////////////////////////
- //[tutorial_roman_ones
- struct ones_ : qi::symbols<char, unsigned>
- {
- ones_()
- {
- add
- ("I" , 1)
- ("II" , 2)
- ("III" , 3)
- ("IV" , 4)
- ("V" , 5)
- ("VI" , 6)
- ("VII" , 7)
- ("VIII" , 8)
- ("IX" , 9)
- ;
- }
- } ones;
- //]
- ///////////////////////////////////////////////////////////////////////////////
- // roman (numerals) grammar
- //
- // Note the use of the || operator. The expression
- // a || b reads match a or b and in sequence. Try
- // defining the roman numerals grammar in YACC or
- // PCCTS. Spirit rules! :-)
- ///////////////////////////////////////////////////////////////////////////////
- //[tutorial_roman_grammar
- template <typename Iterator>
- struct roman : qi::grammar<Iterator, unsigned()>
- {
- roman() : roman::base_type(start)
- {
- using qi::eps;
- using qi::lit;
- using qi::_val;
- using qi::_1;
- using ascii::char_;
- start = eps [_val = 0] >>
- (
- +lit('M') [_val += 1000]
- || hundreds [_val += _1]
- || tens [_val += _1]
- || ones [_val += _1]
- )
- ;
- }
- qi::rule<Iterator, unsigned()> start;
- };
- //]
- }
- ///////////////////////////////////////////////////////////////////////////////
- // Main program
- ///////////////////////////////////////////////////////////////////////////////
- int
- main()
- {
- std::cout << "/////////////////////////////////////////////////////////\n\n";
- std::cout << "\t\tRoman Numerals Parser\n\n";
- std::cout << "/////////////////////////////////////////////////////////\n\n";
- std::cout << "Type a Roman Numeral ...or [q or Q] to quit\n\n";
- typedef std::string::const_iterator iterator_type;
- typedef client::roman<iterator_type> roman;
- roman roman_parser; // Our grammar
- std::string str;
- unsigned result;
- 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();
- //[tutorial_roman_grammar_parse
- bool r = parse(iter, end, roman_parser, result);
- if (r && iter == end)
- {
- std::cout << "-------------------------\n";
- std::cout << "Parsing succeeded\n";
- std::cout << "result = " << result << std::endl;
- 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;
- }
|