1/*============================================================================= 2 Copyright (c) 2003 Hartmut Kaiser 3 http://spirit.sourceforge.net/ 4 5 Use, modification and distribution is subject to the Boost Software 6 License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at 7 http://www.boost.org/LICENSE_1_0.txt) 8=============================================================================*/ 9#ifndef BOOST_SPIRIT_SELECT_IPP 10#define BOOST_SPIRIT_SELECT_IPP 11 12#include <boost/spirit/home/classic/core/parser.hpp> 13#include <boost/spirit/home/classic/core/composite/composite.hpp> 14#include <boost/spirit/home/classic/meta/as_parser.hpp> 15 16/////////////////////////////////////////////////////////////////////////////// 17namespace boost { namespace spirit { 18 19BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN 20 21/////////////////////////////////////////////////////////////////////////////// 22namespace impl { 23 24/////////////////////////////////////////////////////////////////////////////// 25template <typename ParserT> 26struct as_embedded_parser : public as_parser<ParserT> 27{ 28 typedef typename as_parser<ParserT>::type::derived_t::embed_t type; 29}; 30 31/////////////////////////////////////////////////////////////////////////////// 32 33// no implementation here to catch unknown BehaviourT template arguments 34template <typename ResultT, typename BehaviourT> 35struct select_match_gen; 36 37// implementation for the select_default_no_fail behaviour 38template <typename ResultT> 39struct select_match_gen<ResultT, select_default_no_fail> { 40 41 template <typename ScannerT> 42 static ResultT 43 do_ (ScannerT const &scan) 44 { 45 return scan.create_match(0, -1, scan.first, scan.first); 46 } 47}; 48 49// implementation for the select_default_fail behaviour 50template <typename ResultT> 51struct select_match_gen<ResultT, select_default_fail> { 52 53 template <typename ScannerT> 54 static ResultT 55 do_ (ScannerT const &scan) 56 { 57 return scan.no_match(); 58 } 59}; 60 61/////////////////////////////////////////////////////////////////////////////// 62template <int N, typename ResultT, typename TupleT, typename BehaviourT> 63struct parse_tuple_element { 64 65 BOOST_STATIC_CONSTANT(int, index = (TupleT::length - N)); 66 67 template <typename ScannerT> 68 static ResultT 69 do_(TupleT const &t, ScannerT const &scan) 70 { 71 typedef typename ::phoenix::tuple_element<index, TupleT>::type parser_t; 72 typedef typename ScannerT::iterator_t iterator_t; 73 typedef typename parser_result<parser_t, ScannerT>::type result_t; 74 75 iterator_t save(scan.first); 76 result_t result(t[::phoenix::tuple_index<index>()].parse(scan)); 77 78 if (result) { 79 return scan.create_match(result.length(), TupleT::length - N, 80 save, scan.first); 81 } 82 scan.first = save; // reset the input stream 83 return parse_tuple_element<N-1, ResultT, TupleT, BehaviourT>:: 84 do_(t, scan); 85 } 86}; 87 88template <typename ResultT, typename TupleT, typename BehaviourT> 89struct parse_tuple_element<1, ResultT, TupleT, BehaviourT> { 90 91 BOOST_STATIC_CONSTANT(int, index = (TupleT::length - 1)); 92 93 template <typename ScannerT> 94 static ResultT 95 do_(TupleT const &t, ScannerT const &scan) 96 { 97 typedef typename ::phoenix::tuple_element<index, TupleT>::type parser_t; 98 typedef typename ScannerT::iterator_t iterator_t; 99 typedef typename parser_result<parser_t, ScannerT>::type result_t; 100 101 iterator_t save(scan.first); 102 result_t result(t[::phoenix::tuple_index<index>()].parse(scan)); 103 104 if (result) { 105 return scan.create_match(result.length(), TupleT::length - 1, 106 save, scan.first); 107 } 108 scan.first = save; // reset the input stream 109 return select_match_gen<ResultT, BehaviourT>::do_(scan); 110 } 111}; 112 113/////////////////////////////////////////////////////////////////////////////// 114} // namespace impl 115 116BOOST_SPIRIT_CLASSIC_NAMESPACE_END 117 118}} // namespace boost::spirit 119 120#endif // BOOST_SPIRIT_SELECT_IPP 121