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- /*=============================================================================
- Copyright (c) 2002-2003 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 parser for a real number parser that parses thousands separated numbers
- // with at most two decimal places and no exponent. This is discussed in the
- // "Numerics" chapter in the Spirit User's Guide.
- //
- // [ JDG 12/16/2003 ]
- //
- ///////////////////////////////////////////////////////////////////////////////
- #include <boost/spirit/include/classic_core.hpp>
- #include <boost/spirit/include/classic_assign_actor.hpp>
- #include <iostream>
- #include <string>
- ///////////////////////////////////////////////////////////////////////////////
- using namespace std;
- using namespace BOOST_SPIRIT_CLASSIC_NS;
- template <typename T>
- struct ts_real_parser_policies : public ureal_parser_policies<T>
- {
- // These policies can be used to parse thousand separated
- // numbers with at most 2 decimal digits after the decimal
- // point. e.g. 123,456,789.01
- typedef uint_parser<int, 10, 1, 2> uint2_t;
- typedef uint_parser<T, 10, 1, -1> uint_parser_t;
- typedef int_parser<int, 10, 1, -1> int_parser_t;
- ////////////////////////////////// 2 decimal places Max
- template <typename ScannerT>
- static typename parser_result<uint2_t, ScannerT>::type
- parse_frac_n(ScannerT& scan)
- { return uint2_t().parse(scan); }
- ////////////////////////////////// No exponent
- template <typename ScannerT>
- static typename parser_result<chlit<>, ScannerT>::type
- parse_exp(ScannerT& scan)
- { return scan.no_match(); }
- ////////////////////////////////// No exponent
- template <typename ScannerT>
- static typename parser_result<int_parser_t, ScannerT>::type
- parse_exp_n(ScannerT& scan)
- { return scan.no_match(); }
- ////////////////////////////////// Thousands separated numbers
- template <typename ScannerT>
- static typename parser_result<uint_parser_t, ScannerT>::type
- parse_n(ScannerT& scan)
- {
- typedef typename parser_result<uint_parser_t, ScannerT>::type RT;
- static uint_parser<unsigned, 10, 1, 3> uint3_p;
- static uint_parser<unsigned, 10, 3, 3> uint3_3_p;
- if (RT hit = uint3_p.parse(scan))
- {
- T n;
- typedef typename ScannerT::iterator_t iterator_t;
- iterator_t save = scan.first;
- while (match<> next = (',' >> uint3_3_p[assign_a(n)]).parse(scan))
- {
- hit.value((hit.value() * 1000) + n);
- scan.concat_match(hit, next);
- save = scan.first;
- }
- scan.first = save;
- return hit;
- // Note: On erroneous input such as "123,45", the result should
- // be a partial match "123". 'save' is used to makes sure that
- // the scanner position is placed at the last *valid* parse
- // position.
- }
- return scan.no_match();
- }
- };
- real_parser<double, ts_real_parser_policies<double> > const
- ts_real_p = real_parser<double, ts_real_parser_policies<double> >();
- ////////////////////////////////////////////////////////////////////////////
- //
- // Main program
- //
- ////////////////////////////////////////////////////////////////////////////
- int
- main()
- {
- cout << "/////////////////////////////////////////////////////////\n\n";
- cout << "\t\tA real number parser that parses thousands separated\n";
- cout << "\t\tnumbers with at most two decimal places and no exponent...\n\n";
- cout << "/////////////////////////////////////////////////////////\n\n";
- cout << "Give me a number.\n";
- cout << "Type [q or Q] to quit\n\n";
- string str;
- double n;
- while (getline(cin, str))
- {
- if (str.empty() || str[0] == 'q' || str[0] == 'Q')
- break;
- if (parse(str.c_str(), ts_real_p[assign_a(n)]).full)
- {
- cout << "-------------------------\n";
- cout << "Parsing succeeded\n";
- cout << str << " Parses OK: " << endl;
- cout << "n=" << n << endl;
- cout << "-------------------------\n";
- }
- else
- {
- cout << "-------------------------\n";
- cout << "Parsing failed\n";
- cout << "-------------------------\n";
- }
- }
- cout << "Bye... :-) \n\n";
- return 0;
- }
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