93 lines
2.9 KiB
C++
93 lines
2.9 KiB
C++
// Copyright (c) 2001-2010 Hartmut Kaiser
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//
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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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// This example demonstrates a trick allowing to adapt a template data
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// structure as a Fusion sequence in order to use is for direct attribute
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// propagation. For more information see
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// http://boost-spirit.com/home/2010/02/08/how-to-adapt-templates-as-a-fusion-sequence
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#include <boost/spirit/include/qi.hpp>
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namespace qi = boost::spirit::qi;
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namespace fusion = boost::fusion;
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namespace client
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{
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template <typename A, typename B>
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struct data
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{
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A a;
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B b;
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};
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template <typename Iterator, typename A, typename B>
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struct data_grammar : qi::grammar<Iterator, data<A, B>()>
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{
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data_grammar() : data_grammar::base_type(start)
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{
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start = real_start;
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real_start = qi::auto_ >> ',' >> qi::auto_;
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}
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qi::rule<Iterator, data<A, B>()> start;
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qi::rule<Iterator, fusion::vector<A&, B&>()> real_start;
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};
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}
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namespace boost { namespace spirit { namespace traits
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{
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template <typename A, typename B>
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struct transform_attribute<client::data<A, B>, fusion::vector<A&, B&>, qi::domain>
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{
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typedef fusion::vector<A&, B&> type;
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static type pre(client::data<A, B>& val) { return type(val.a, val.b); }
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static void post(client::data<A, B>&, fusion::vector<A&, B&> const&) {}
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static void fail(client::data<A, B>&) {}
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};
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}}}
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///////////////////////////////////////////////////////////////////////////////
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int main()
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{
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std::cout << "/////////////////////////////////////////////////////////\n\n";
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std::cout << "\t\tA parser for Spirit utilizing an adapted template ...\n\n";
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std::cout << "/////////////////////////////////////////////////////////\n\n";
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std::cout << "Give me two comma separated integers:\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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client::data_grammar<std::string::const_iterator, long, int> g; // Our grammar
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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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client::data<long, int> d;
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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, g, qi::space, d);
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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 << "got: " << d.a << "," << d.b << std::endl;
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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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return 0;
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}
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