/Src/Dependencies/Boost/boost/spirit/home/karma/detail/attributes.hpp

  1//  Copyright (c) 2001-2011 Hartmut Kaiser
  2//  Copyright (c) 2001-2011 Joel de Guzman
  3//
  4//  Distributed under the Boost Software License, Version 1.0. (See accompanying
  5//  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  6
  7#if !defined(SPIRIT_KARMA_DETAIL_ATTRIBUTES_APR_18_2010_0453PM)
  8#define SPIRIT_KARMA_DETAIL_ATTRIBUTES_APR_18_2010_0453PM
  9
 10#include <boost/spirit/home/karma/domain.hpp>
 11#include <boost/spirit/home/support/attributes_fwd.hpp>
 12#include <boost/spirit/home/support/attributes.hpp>
 13
 14///////////////////////////////////////////////////////////////////////////////
 15namespace boost { namespace spirit { namespace karma
 16{
 17    template <typename Exposed, typename Transformed, typename Enable = void>
 18    struct transform_attribute
 19    {
 20        typedef Transformed type;
 21        static Transformed pre(Exposed& val) 
 22        { 
 23            return Transformed(traits::extract_from<Transformed>(val, unused));
 24        }
 25        // Karma only, no post() and no fail() required
 26    };
 27
 28    template <typename Exposed, typename Transformed>
 29    struct transform_attribute<boost::optional<Exposed> const, Transformed
 30      , typename disable_if<is_same<boost::optional<Exposed>, Transformed> >::type>
 31    {
 32        typedef Transformed const& type;
 33        static Transformed const& pre(boost::optional<Exposed> const& val)
 34        {
 35            return boost::get<Transformed>(val);
 36        }
 37    };
 38
 39    template <typename Attribute>
 40    struct transform_attribute<Attribute const, Attribute>
 41    {
 42        typedef Attribute const& type;
 43        static Attribute const& pre(Attribute const& val) { return val; }
 44        // Karma only, no post() and no fail() required
 45    };
 46
 47    // reference types need special handling
 48    template <typename Exposed, typename Transformed>
 49    struct transform_attribute<Exposed&, Transformed>
 50      : transform_attribute<Exposed, Transformed>
 51    {};
 52
 53    template <typename Exposed, typename Transformed>
 54    struct transform_attribute<Exposed const&, Transformed>
 55      : transform_attribute<Exposed const, Transformed>
 56    {};
 57
 58    template <typename Attribute>
 59    struct transform_attribute<Attribute const&, Attribute>
 60      : transform_attribute<Attribute const, Attribute>
 61    {};
 62
 63    // unused_type needs some special handling as well
 64    template <>
 65    struct transform_attribute<unused_type, unused_type>
 66    {
 67        typedef unused_type type;
 68        static unused_type pre(unused_type) { return unused; }
 69    };
 70
 71    template <>
 72    struct transform_attribute<unused_type const, unused_type>
 73      : transform_attribute<unused_type, unused_type>
 74    {};
 75
 76    template <typename Attribute>
 77    struct transform_attribute<unused_type, Attribute>
 78      : transform_attribute<unused_type, unused_type>
 79    {};
 80
 81    template <typename Attribute>
 82    struct transform_attribute<unused_type const, Attribute>
 83      : transform_attribute<unused_type, unused_type>
 84    {};
 85
 86    template <typename Attribute>
 87    struct transform_attribute<Attribute, unused_type>
 88      : transform_attribute<unused_type, unused_type>
 89    {};
 90
 91    template <typename Attribute>
 92    struct transform_attribute<Attribute const, unused_type>
 93      : transform_attribute<unused_type, unused_type>
 94    {};
 95}}}
 96
 97///////////////////////////////////////////////////////////////////////////////
 98namespace boost { namespace spirit { namespace traits
 99{
100    template <typename Exposed, typename Transformed>
101    struct transform_attribute<Exposed, Transformed, karma::domain>
102      : karma::transform_attribute<Exposed, Transformed>
103    {};
104}}}
105
106#endif
107
108