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f44479bcd3
It is better to manage warnings on our side to know what warnings we need to fix or suppress, and the only thing that header does is disabling deprecation warnings on MSVC and ICC which we would prefer to not show to users.
118 lines
3.8 KiB
C++
118 lines
3.8 KiB
C++
/*=============================================================================
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Copyright (c) 2001-2011 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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// Plain calculator example demonstrating the grammar. The parser is a
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// syntax checker only and does not do any semantic evaluation.
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//
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// [ JDG May 10, 2002 ] spirit1
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// [ JDG March 4, 2007 ] spirit2
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// [ JDG February 21, 2011 ] spirit2.5
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//
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///////////////////////////////////////////////////////////////////////////////
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// Spirit v2.5 allows you to suppress automatic generation
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// of predefined terminals to speed up complation. With
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// BOOST_SPIRIT_NO_PREDEFINED_TERMINALS defined, you are
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// responsible in creating instances of the terminals that
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// you need (e.g. see qi::uint_type uint_ below).
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#define BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
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#include <boost/spirit/include/qi.hpp>
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#include <iostream>
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#include <string>
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namespace client
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{
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namespace qi = boost::spirit::qi;
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namespace ascii = boost::spirit::ascii;
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///////////////////////////////////////////////////////////////////////////////
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// Our calculator grammar
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///////////////////////////////////////////////////////////////////////////////
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template <typename Iterator>
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struct calculator : qi::grammar<Iterator, ascii::space_type>
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{
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calculator() : calculator::base_type(expression)
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{
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qi::uint_type uint_;
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expression =
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term
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>> *( ('+' >> term)
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| ('-' >> term)
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)
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;
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term =
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factor
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>> *( ('*' >> factor)
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| ('/' >> factor)
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)
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;
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factor =
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uint_
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| '(' >> expression >> ')'
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| ('-' >> factor)
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| ('+' >> factor)
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;
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}
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qi::rule<Iterator, ascii::space_type> expression, term, factor;
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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 << "Expression parser...\n\n";
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std::cout << "/////////////////////////////////////////////////////////\n\n";
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std::cout << "Type an expression...or [q or Q] to quit\n\n";
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typedef std::string::const_iterator iterator_type;
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typedef client::calculator<iterator_type> calculator;
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boost::spirit::ascii::space_type space; // Our skipper
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calculator calc; // Our grammar
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std::string str;
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while (std::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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std::string::const_iterator iter = str.begin();
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std::string::const_iterator end = str.end();
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bool r = phrase_parse(iter, end, calc, space);
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if (r && iter == end)
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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 << "-------------------------\n";
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}
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else
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{
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std::string rest(iter, end);
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std::cout << "-------------------------\n";
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std::cout << "Parsing failed\n";
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std::cout << "stopped at: \" " << rest << "\"\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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