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120 lines
4.0 KiB
120 lines
4.0 KiB
/*============================================================================= |
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Copyright (c) 2003 Hartmut Kaiser |
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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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#ifndef BOOST_SPIRIT_SELECT_IPP |
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#define BOOST_SPIRIT_SELECT_IPP |
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#include <boost/spirit/home/classic/core/parser.hpp> |
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#include <boost/spirit/home/classic/core/composite/composite.hpp> |
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#include <boost/spirit/home/classic/meta/as_parser.hpp> |
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/////////////////////////////////////////////////////////////////////////////// |
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namespace boost { namespace spirit { |
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BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN |
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/////////////////////////////////////////////////////////////////////////////// |
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namespace impl { |
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/////////////////////////////////////////////////////////////////////////////// |
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template <typename ParserT> |
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struct as_embedded_parser : public as_parser<ParserT> |
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{ |
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typedef typename as_parser<ParserT>::type::derived_t::embed_t type; |
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}; |
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/////////////////////////////////////////////////////////////////////////////// |
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// no implementation here to catch unknown BehaviourT template arguments |
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template <typename ResultT, typename BehaviourT> |
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struct select_match_gen; |
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// implementation for the select_default_no_fail behaviour |
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template <typename ResultT> |
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struct select_match_gen<ResultT, select_default_no_fail> { |
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template <typename ScannerT> |
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static ResultT |
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do_ (ScannerT const &scan) |
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{ |
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return scan.create_match(0, -1, scan.first, scan.first); |
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} |
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}; |
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// implementation for the select_default_fail behaviour |
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template <typename ResultT> |
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struct select_match_gen<ResultT, select_default_fail> { |
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template <typename ScannerT> |
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static ResultT |
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do_ (ScannerT const &scan) |
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{ |
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return scan.no_match(); |
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} |
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}; |
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/////////////////////////////////////////////////////////////////////////////// |
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template <int N, typename ResultT, typename TupleT, typename BehaviourT> |
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struct parse_tuple_element { |
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BOOST_STATIC_CONSTANT(int, index = (TupleT::length - N)); |
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template <typename ScannerT> |
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static ResultT |
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do_(TupleT const &t, ScannerT const &scan) |
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{ |
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typedef typename ::phoenix::tuple_element<index, TupleT>::type parser_t; |
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typedef typename ScannerT::iterator_t iterator_t; |
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typedef typename parser_result<parser_t, ScannerT>::type result_t; |
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iterator_t save(scan.first); |
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result_t result(t[::phoenix::tuple_index<index>()].parse(scan)); |
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if (result) { |
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return scan.create_match(result.length(), TupleT::length - N, |
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save, scan.first); |
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} |
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scan.first = save; // reset the input stream |
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return parse_tuple_element<N-1, ResultT, TupleT, BehaviourT>:: |
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do_(t, scan); |
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} |
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}; |
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template <typename ResultT, typename TupleT, typename BehaviourT> |
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struct parse_tuple_element<1, ResultT, TupleT, BehaviourT> { |
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BOOST_STATIC_CONSTANT(int, index = (TupleT::length - 1)); |
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template <typename ScannerT> |
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static ResultT |
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do_(TupleT const &t, ScannerT const &scan) |
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{ |
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typedef typename ::phoenix::tuple_element<index, TupleT>::type parser_t; |
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typedef typename ScannerT::iterator_t iterator_t; |
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typedef typename parser_result<parser_t, ScannerT>::type result_t; |
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iterator_t save(scan.first); |
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result_t result(t[::phoenix::tuple_index<index>()].parse(scan)); |
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if (result) { |
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return scan.create_match(result.length(), TupleT::length - 1, |
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save, scan.first); |
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} |
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scan.first = save; // reset the input stream |
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return select_match_gen<ResultT, BehaviourT>::do_(scan); |
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} |
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}; |
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/////////////////////////////////////////////////////////////////////////////// |
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} // namespace impl |
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BOOST_SPIRIT_CLASSIC_NAMESPACE_END |
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}} // namespace boost::spirit |
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#endif // BOOST_SPIRIT_SELECT_IPP
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