61 lines
1.3 KiB
C++
61 lines
1.3 KiB
C++
/*==============================================================================
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Copyright (c) 2005-2010 Joel de Guzman
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Copyright (c) 2011 Thomas Heller
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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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#include <boost/phoenix/core.hpp>
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namespace phoenix = boost::phoenix;
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namespace proto = boost::proto;
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// define the expression
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namespace expression
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{
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template <typename Lhs, typename Rhs>
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struct plus
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: phoenix::expr<proto::tag::plus, Lhs, Rhs>
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{};
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}
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// extend the grammar, to recognice the expression
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namespace boost { namespace phoenix {
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template <>
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struct meta_grammar::case_<proto::tag::plus>
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: enable_rule<
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::expression::plus<
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meta_grammar
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, meta_grammar
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>
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>
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{};
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}}
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// build a generator
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template <typename Lhs, typename Rhs>
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typename expression::plus<Lhs, Rhs>::type
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plus(Lhs const & lhs, Rhs const & rhs)
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{
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return expression::plus<Lhs, Rhs>::make(lhs, rhs);
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}
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#include <boost/proto/proto.hpp>
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#include <iostream>
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int main()
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{
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plus(6, 5);
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proto::display_expr(plus(6, 5));
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std::cout << plus(5, 6)() << "\n";
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}
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