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- /*=============================================================================
- 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 parser for summing a comma-separated list of numbers using phoenix.
- //
- // [ JDG June 28, 2002 ] spirit1
- // [ JDG March 24, 2007 ] spirit2
- // [ JDG May 12, 2015 ] spirit X3
- //
- ///////////////////////////////////////////////////////////////////////////////
- #include <boost/config/warning_disable.hpp>
- #include <boost/spirit/home/x3.hpp>
- #include <iostream>
- #include <string>
- namespace client
- {
- namespace x3 = boost::spirit::x3;
- namespace ascii = boost::spirit::x3::ascii;
- using x3::double_;
- using ascii::space;
- using x3::_attr;
- ///////////////////////////////////////////////////////////////////////////
- // Our adder
- ///////////////////////////////////////////////////////////////////////////
- template <typename Iterator>
- bool adder(Iterator first, Iterator last, double& n)
- {
- auto assign = [&](auto& ctx){ n = _attr(ctx); };
- auto add = [&](auto& ctx){ n += _attr(ctx); };
- bool r = x3::phrase_parse(first, last,
- // Begin grammar
- (
- double_[assign] >> *(',' >> double_[add])
- )
- ,
- // End grammar
- space);
- if (first != last) // fail if we did not get a full match
- return false;
- return r;
- }
- }
- ////////////////////////////////////////////////////////////////////////////
- // Main program
- ////////////////////////////////////////////////////////////////////////////
- int
- main()
- {
- std::cout << "/////////////////////////////////////////////////////////\n\n";
- std::cout << "\t\tA parser for summing a list of numbers...\n\n";
- std::cout << "/////////////////////////////////////////////////////////\n\n";
- std::cout << "Give me a comma separated list of numbers.\n";
- std::cout << "The numbers are added using Phoenix.\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;
- double n;
- if (client::adder(str.begin(), str.end(), n))
- {
- std::cout << "-------------------------\n";
- std::cout << "Parsing succeeded\n";
- std::cout << str << " Parses OK: " << std::endl;
- std::cout << "sum = " << n;
- std::cout << "\n-------------------------\n";
- }
- else
- {
- std::cout << "-------------------------\n";
- std::cout << "Parsing failed\n";
- std::cout << "-------------------------\n";
- }
- }
- std::cout << "Bye... :-) \n\n";
- return 0;
- }
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