| 1 | /*============================================================================= |
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| 2 | Copyright (c) 2003 Hartmut Kaiser |
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| 3 | http://spirit.sourceforge.net/ |
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| 4 | |
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| 5 | Use, modification and distribution is subject to the Boost Software |
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| 6 | License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
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| 7 | http://www.boost.org/LICENSE_1_0.txt) |
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| 8 | =============================================================================*/ |
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| 9 | #ifndef BOOST_SPIRIT_SELECT_IPP |
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| 10 | #define BOOST_SPIRIT_SELECT_IPP |
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| 11 | |
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| 12 | #include <boost/spirit/core/parser.hpp> |
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| 13 | #include <boost/spirit/core/composite/composite.hpp> |
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| 14 | #include <boost/spirit/meta/as_parser.hpp> |
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| 15 | |
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| 16 | /////////////////////////////////////////////////////////////////////////////// |
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| 17 | namespace boost { namespace spirit { |
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| 18 | |
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| 19 | /////////////////////////////////////////////////////////////////////////////// |
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| 20 | namespace impl { |
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| 21 | |
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| 22 | /////////////////////////////////////////////////////////////////////////////// |
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| 23 | template <typename ParserT> |
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| 24 | struct as_embedded_parser : public as_parser<ParserT> |
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| 25 | { |
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| 26 | typedef typename as_parser<ParserT>::type::derived_t::embed_t type; |
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| 27 | }; |
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| 28 | |
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| 29 | /////////////////////////////////////////////////////////////////////////////// |
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| 30 | |
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| 31 | // no implementation here to catch unknown BehaviourT template arguments |
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| 32 | template <typename ResultT, typename BehaviourT> |
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| 33 | struct select_match_gen; |
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| 34 | |
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| 35 | // implementation for the select_default_no_fail behaviour |
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| 36 | template <typename ResultT> |
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| 37 | struct select_match_gen<ResultT, select_default_no_fail> { |
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| 38 | |
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| 39 | template <typename ScannerT> |
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| 40 | static ResultT |
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| 41 | do_ (ScannerT const &scan) |
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| 42 | { |
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| 43 | return scan.create_match(0, -1, scan.first, scan.first); |
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| 44 | } |
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| 45 | }; |
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| 46 | |
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| 47 | // implementation for the select_default_fail behaviour |
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| 48 | template <typename ResultT> |
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| 49 | struct select_match_gen<ResultT, select_default_fail> { |
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| 50 | |
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| 51 | template <typename ScannerT> |
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| 52 | static ResultT |
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| 53 | do_ (ScannerT const &scan) |
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| 54 | { |
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| 55 | return scan.no_match(); |
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| 56 | } |
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| 57 | }; |
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| 58 | |
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| 59 | /////////////////////////////////////////////////////////////////////////////// |
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| 60 | template <int N, typename ResultT, typename TupleT, typename BehaviourT> |
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| 61 | struct parse_tuple_element { |
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| 62 | |
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| 63 | BOOST_STATIC_CONSTANT(int, index = (TupleT::length - N)); |
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| 64 | |
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| 65 | template <typename ScannerT> |
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| 66 | static ResultT |
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| 67 | do_(TupleT const &t, ScannerT const &scan) |
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| 68 | { |
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| 69 | typedef typename phoenix::tuple_element<index, TupleT>::type parser_t; |
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| 70 | typedef typename ScannerT::iterator_t iterator_t; |
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| 71 | typedef typename parser_result<parser_t, ScannerT>::type result_t; |
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| 72 | |
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| 73 | iterator_t save(scan.first); |
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| 74 | result_t result(t[phoenix::tuple_index<index>()].parse(scan)); |
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| 75 | |
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| 76 | if (result) { |
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| 77 | return scan.create_match(result.length(), TupleT::length - N, |
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| 78 | save, scan.first); |
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| 79 | } |
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| 80 | scan.first = save; // reset the input stream |
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| 81 | return parse_tuple_element<N-1, ResultT, TupleT, BehaviourT>:: |
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| 82 | do_(t, scan); |
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| 83 | } |
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| 84 | }; |
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| 85 | |
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| 86 | template <typename ResultT, typename TupleT, typename BehaviourT> |
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| 87 | struct parse_tuple_element<1, ResultT, TupleT, BehaviourT> { |
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| 88 | |
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| 89 | BOOST_STATIC_CONSTANT(int, index = (TupleT::length - 1)); |
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| 90 | |
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| 91 | template <typename ScannerT> |
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| 92 | static ResultT |
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| 93 | do_(TupleT const &t, ScannerT const &scan) |
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| 94 | { |
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| 95 | typedef typename phoenix::tuple_element<index, TupleT>::type parser_t; |
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| 96 | typedef typename ScannerT::iterator_t iterator_t; |
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| 97 | typedef typename parser_result<parser_t, ScannerT>::type result_t; |
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| 98 | |
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| 99 | iterator_t save(scan.first); |
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| 100 | result_t result(t[phoenix::tuple_index<index>()].parse(scan)); |
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| 101 | |
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| 102 | if (result) { |
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| 103 | return scan.create_match(result.length(), TupleT::length - 1, |
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| 104 | save, scan.first); |
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| 105 | } |
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| 106 | scan.first = save; // reset the input stream |
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| 107 | return select_match_gen<ResultT, BehaviourT>::do_(scan); |
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| 108 | } |
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| 109 | }; |
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| 110 | |
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| 111 | /////////////////////////////////////////////////////////////////////////////// |
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| 112 | } // namespace impl |
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| 113 | }} // namespace boost::spirit |
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| 114 | |
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| 115 | #endif // BOOST_SPIRIT_SELECT_IPP |
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