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- /*=============================================================================
- Copyright (c) 2001-2003 Joel de Guzman
- 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)
- =============================================================================*/
- ///////////////////////////////////////////////////////////////////////////////
- //
- // A complex number micro parser (using subrules)
- //
- // [ JDG 5/10/2002 ]
- //
- ///////////////////////////////////////////////////////////////////////////////
- #include <boost/spirit/include/classic_core.hpp>
- #include <iostream>
- #include <complex>
- #include <string>
- ///////////////////////////////////////////////////////////////////////////////
- using namespace std;
- using namespace BOOST_SPIRIT_CLASSIC_NS;
- ///////////////////////////////////////////////////////////////////////////////
- //
- // Our complex number micro parser
- //
- ///////////////////////////////////////////////////////////////////////////////
- bool
- parse_complex(char const* str, complex<double>& c)
- {
- double rN = 0.0;
- double iN = 0.0;
- subrule<0> first;
- subrule<1> r;
- subrule<2> i;
- if (parse(str,
- // Begin grammar
- (
- first = '(' >> r >> !(',' >> i) >> ')' | r,
- r = real_p[assign(rN)],
- i = real_p[assign(iN)]
- )
- ,
- // End grammar
- space_p).full)
- {
- c = complex<double>(rN, iN);
- return true;
- }
- else
- {
- return false;
- }
- }
- ////////////////////////////////////////////////////////////////////////////
- //
- // Main program
- //
- ////////////////////////////////////////////////////////////////////////////
- int
- main()
- {
- cout << "/////////////////////////////////////////////////////////\n\n";
- cout << "\t\tA complex number micro parser for Spirit...\n\n";
- cout << "/////////////////////////////////////////////////////////\n\n";
- cout << "Give me a complex number of the form r or (r) or (r,i) \n";
- cout << "Type [q or Q] to quit\n\n";
- string str;
- while (getline(cin, str))
- {
- if (str.empty() || str[0] == 'q' || str[0] == 'Q')
- break;
- complex<double> c;
- if (parse_complex(str.c_str(), c))
- {
- cout << "-------------------------\n";
- cout << "Parsing succeeded\n";
- cout << str << " Parses OK: " << c << endl;
- cout << "-------------------------\n";
- }
- else
- {
- cout << "-------------------------\n";
- cout << "Parsing failed\n";
- cout << "-------------------------\n";
- }
- }
- cout << "Bye... :-) \n\n";
- return 0;
- }
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