107 lines
3.1 KiB
C++
107 lines
3.1 KiB
C++
/*=============================================================================
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Copyright (c) 2002-2010 Joel de Guzman
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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///////////////////////////////////////////////////////////////////////////////
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//
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// A parser for summing a comma-separated list of numbers using phoenix.
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//
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// [ JDG June 28, 2002 ] spirit1
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// [ JDG March 24, 2007 ] spirit2
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//
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///////////////////////////////////////////////////////////////////////////////
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#include <boost/config/warning_disable.hpp>
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//[tutorial_adder_includes
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#include <boost/spirit/include/qi.hpp>
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#include <boost/spirit/include/phoenix_core.hpp>
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#include <boost/spirit/include/phoenix_operator.hpp>
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#include <iostream>
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#include <string>
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//]
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namespace client
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{
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//[tutorial_adder_using
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namespace qi = boost::spirit::qi;
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namespace ascii = boost::spirit::ascii;
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namespace phoenix = boost::phoenix;
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using qi::double_;
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using qi::_1;
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using ascii::space;
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using phoenix::ref;
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//]
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///////////////////////////////////////////////////////////////////////////
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// Our adder
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///////////////////////////////////////////////////////////////////////////
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//[tutorial_adder
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template <typename Iterator>
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bool adder(Iterator first, Iterator last, double& n)
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{
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bool r = qi::phrase_parse(first, last,
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// Begin grammar
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(
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double_[ref(n) = _1] >> *(',' >> double_[ref(n) += _1])
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)
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,
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// End grammar
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space);
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if (first != last) // fail if we did not get a full match
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return false;
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return r;
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}
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//]
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}
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////////////////////////////////////////////////////////////////////////////
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// Main program
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////////////////////////////////////////////////////////////////////////////
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int
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main()
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{
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std::cout << "/////////////////////////////////////////////////////////\n\n";
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std::cout << "\t\tA parser for summing a list of numbers...\n\n";
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std::cout << "/////////////////////////////////////////////////////////\n\n";
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std::cout << "Give me a comma separated list of numbers.\n";
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std::cout << "The numbers are added using Phoenix.\n";
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std::cout << "Type [q or Q] to quit\n\n";
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std::string str;
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while (getline(std::cin, str))
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{
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if (str.empty() || str[0] == 'q' || str[0] == 'Q')
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break;
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double n;
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if (client::adder(str.begin(), str.end(), n))
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{
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std::cout << "-------------------------\n";
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std::cout << "Parsing succeeded\n";
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std::cout << str << " Parses OK: " << std::endl;
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std::cout << "sum = " << n;
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std::cout << "\n-------------------------\n";
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}
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else
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{
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std::cout << "-------------------------\n";
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std::cout << "Parsing failed\n";
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std::cout << "-------------------------\n";
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}
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}
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std::cout << "Bye... :-) \n\n";
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return 0;
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}
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