ceph/src/boost/libs/spirit/include/boost/spirit/home/classic/dynamic/impl/select.ipp

   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 ///////////////////////////////////////////////////////////////////////////////
  17 namespace boost { namespace spirit {
  18
  19 BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
  20
  21 ///////////////////////////////////////////////////////////////////////////////
  22 namespace impl {
  23
  24 ///////////////////////////////////////////////////////////////////////////////
  25 template <typename ParserT>
  26 struct 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
  34 template <typename ResultT, typename BehaviourT>
  35 struct select_match_gen;
  36
  37 // implementation for the select_default_no_fail behaviour
  38 template <typename ResultT>
  39 struct 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
  50 template <typename ResultT>
  51 struct 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 ///////////////////////////////////////////////////////////////////////////////
  62 template <int N, typename ResultT, typename TupleT, typename BehaviourT>
  63 struct 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
  88 template <typename ResultT, typename TupleT, typename BehaviourT>
  89 struct 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
 116 BOOST_SPIRIT_CLASSIC_NAMESPACE_END
 117
 118 }}  // namespace boost::spirit
 119
 120 #endif  // BOOST_SPIRIT_SELECT_IPP