ceph/src/boost/libs/spirit/include/boost/spirit/home/classic/meta/as_parser.hpp

   1 /*=============================================================================
   2     Copyright (c) 2002-2003 Joel de Guzman
   3     Copyright (c) 2002-2003 Hartmut Kaiser
   4     http://spirit.sourceforge.net/
   5
   6   Distributed under the Boost Software License, Version 1.0. (See accompanying
   7   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   8 =============================================================================*/
   9 #if !defined(BOOST_SPIRIT_AS_PARSER_HPP)
  10 #define BOOST_SPIRIT_AS_PARSER_HPP
  11
  12 #include <boost/spirit/home/classic/namespace.hpp>
  13 #include <boost/spirit/home/classic/core/primitives/primitives.hpp>
  14
  15 namespace boost { namespace spirit {
  16
  17 BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
  18
  19     ///////////////////////////////////////////////////////////////////////////
  20     //
  21     //  Helper templates to derive the parser type from an auxilliary type
  22     //  and to generate an object of the required parser type given an
  23     //  auxilliary object. Supported types to convert are parsers,
  24     //  single characters and character strings.
  25     //
  26     ///////////////////////////////////////////////////////////////////////////
  27     namespace impl
  28     {
  29         template<typename T>
  30         struct default_as_parser
  31         {
  32             typedef T type;
  33             static type const& convert(type const& p)
  34             {
  35                 return p;
  36             }
  37         };
  38
  39         struct char_as_parser
  40         {
  41             typedef chlit<char> type;
  42             static type convert(char ch)
  43             {
  44                 return type(ch);
  45             }
  46         };
  47
  48         struct wchar_as_parser
  49         {
  50             typedef chlit<wchar_t> type;
  51             static type convert(wchar_t ch)
  52             {
  53                 return type(ch);
  54             }
  55         };
  56
  57         struct string_as_parser
  58         {
  59             typedef strlit<char const*> type;
  60             static type convert(char const* str)
  61             {
  62                 return type(str);
  63             }
  64         };
  65
  66         struct wstring_as_parser
  67         {
  68             typedef strlit<wchar_t const*> type;
  69             static type convert(wchar_t const* str)
  70             {
  71                 return type(str);
  72             }
  73         };
  74     }
  75
  76     template<typename T>
  77     struct as_parser : impl::default_as_parser<T> {};
  78
  79     template<>
  80     struct as_parser<char> : impl::char_as_parser {};
  81
  82     template<>
  83     struct as_parser<wchar_t> : impl::wchar_as_parser {};
  84
  85     template<>
  86     struct as_parser<char*> : impl::string_as_parser {};
  87
  88     template<>
  89     struct as_parser<char const*> : impl::string_as_parser {};
  90
  91     template<>
  92     struct as_parser<wchar_t*> : impl::wstring_as_parser {};
  93
  94     template<>
  95     struct as_parser<wchar_t const*> : impl::wstring_as_parser {};
  96
  97     template<int N>
  98     struct as_parser<char[N]> : impl::string_as_parser {};
  99
 100     template<int N>
 101     struct as_parser<wchar_t[N]> : impl::wstring_as_parser {};
 102
 103     template<int N>
 104     struct as_parser<char const[N]> : impl::string_as_parser {};
 105
 106     template<int N>
 107     struct as_parser<wchar_t const[N]> : impl::wstring_as_parser {};
 108
 109 BOOST_SPIRIT_CLASSIC_NAMESPACE_END
 110
 111 }} // namespace BOOST_SPIRIT_CLASSIC_NS
 112
 113 #endif