1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798 |
- /*=============================================================================
- Copyright (c) 2002-2015 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 parser.
- //
- // [ JDG May 10, 2002 ] spirit1
- // [ JDG May 9, 2007 ] spirit2
- // [ JDG May 12, 2015 ] spirit X3
- //
- ///////////////////////////////////////////////////////////////////////////////
- #include <boost/config/warning_disable.hpp>
- #include <boost/spirit/home/x3.hpp>
- #include <iostream>
- #include <string>
- #include <complex>
- ///////////////////////////////////////////////////////////////////////////////
- // Our complex number parser/compiler
- ///////////////////////////////////////////////////////////////////////////////
- namespace client
- {
- template <typename Iterator>
- bool parse_complex(Iterator first, Iterator last, std::complex<double>& c)
- {
- using boost::spirit::x3::double_;
- using boost::spirit::x3::_attr;
- using boost::spirit::x3::phrase_parse;
- using boost::spirit::x3::ascii::space;
- double rN = 0.0;
- double iN = 0.0;
- auto fr = [&](auto& ctx){ rN = _attr(ctx); };
- auto fi = [&](auto& ctx){ iN = _attr(ctx); };
- bool r = phrase_parse(first, last,
- // Begin grammar
- (
- '(' >> double_[fr]
- >> -(',' >> double_[fi]) >> ')'
- | double_[fr]
- ),
- // End grammar
- space);
- if (!r || first != last) // fail if we did not get a full match
- return false;
- c = std::complex<double>(rN, iN);
- return r;
- }
- }
- ////////////////////////////////////////////////////////////////////////////
- // Main program
- ////////////////////////////////////////////////////////////////////////////
- int
- main()
- {
- std::cout << "/////////////////////////////////////////////////////////\n\n";
- std::cout << "\t\tA complex number micro parser 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<double> c;
- if (client::parse_complex(str.begin(), str.end(), c))
- {
- std::cout << "-------------------------\n";
- std::cout << "Parsing succeeded\n";
- std::cout << "got: " << c << std::endl;
- std::cout << "\n-------------------------\n";
- }
- else
- {
- std::cout << "-------------------------\n";
- std::cout << "Parsing failed\n";
- std::cout << "-------------------------\n";
- }
- }
- std::cout << "Bye... :-) \n\n";
- return 0;
- }
|