93 lines
2.8 KiB
C++
93 lines
2.8 KiB
C++
/*=============================================================================
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Copyright (c) 2002-2003 Joel de Guzman
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http://spirit.sourceforge.net/
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Use, modification and distribution is subject to the Boost Software
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License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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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 list of numbers. Demonstrating phoenix
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// This is discussed in the "Phoenix" chapter in the Spirit User's Guide.
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//
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// [ JDG 6/28/2002 ]
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//
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///////////////////////////////////////////////////////////////////////////////
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#include <boost/spirit/include/classic_core.hpp>
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#include <boost/spirit/include/phoenix1_primitives.hpp>
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#include <boost/spirit/include/phoenix1_operators.hpp>
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#include <iostream>
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#include <string>
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///////////////////////////////////////////////////////////////////////////////
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using namespace std;
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using namespace BOOST_SPIRIT_CLASSIC_NS;
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using namespace phoenix;
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///////////////////////////////////////////////////////////////////////////////
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//
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// Our adder
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//
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///////////////////////////////////////////////////////////////////////////////
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template <typename IteratorT>
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bool adder(IteratorT first, IteratorT last, double& n)
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{
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return parse(first, last,
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// Begin grammar
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(
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real_p[var(n) = arg1] >> *(',' >> real_p[var(n) += arg1])
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)
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,
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// End grammar
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space_p).full;
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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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////////////////////////////////////////////////////////////////////////////
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int
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main()
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{
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cout << "/////////////////////////////////////////////////////////\n\n";
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cout << "\t\tA parser for summing a list of numbers...\n\n";
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cout << "/////////////////////////////////////////////////////////\n\n";
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cout << "Give me a comma separated list of numbers.\n";
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cout << "The numbers are added using Phoenix.\n";
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cout << "Type [q or Q] to quit\n\n";
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string str;
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while (getline(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 (adder(str.begin(), str.end(), n))
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{
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cout << "-------------------------\n";
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cout << "Parsing succeeded\n";
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cout << str << " Parses OK: " << endl;
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cout << "sum = " << n;
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cout << "\n-------------------------\n";
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}
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else
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{
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cout << "-------------------------\n";
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cout << "Parsing failed\n";
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cout << "-------------------------\n";
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}
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}
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cout << "Bye... :-) \n\n";
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return 0;
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}
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