Chris@16: //  Copyright (c) 2001-2011 Hartmut Kaiser
Chris@16: //  Copyright (c) 2001-2011 Joel de Guzman
Chris@16: //
Chris@16: //  Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16: //  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #if !defined(SPIRIT_KARMA_DETAIL_ATTRIBUTES_APR_18_2010_0453PM)
Chris@16: #define SPIRIT_KARMA_DETAIL_ATTRIBUTES_APR_18_2010_0453PM
Chris@16: 
Chris@16: #include <boost/spirit/home/karma/domain.hpp>
Chris@16: #include <boost/spirit/home/support/attributes_fwd.hpp>
Chris@16: #include <boost/spirit/home/support/attributes.hpp>
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: namespace boost { namespace spirit { namespace karma
Chris@16: {
Chris@16:     template <typename Exposed, typename Transformed, typename Enable = void>
Chris@16:     struct transform_attribute
Chris@16:     {
Chris@16:         typedef Transformed type;
Chris@16:         static Transformed pre(Exposed& val) 
Chris@16:         { 
Chris@16:             return Transformed(traits::extract_from<Transformed>(val, unused));
Chris@16:         }
Chris@16:         // Karma only, no post() and no fail() required
Chris@16:     };
Chris@16: 
Chris@16:     template <typename Exposed, typename Transformed>
Chris@16:     struct transform_attribute<boost::optional<Exposed> const, Transformed
Chris@16:       , typename disable_if<is_same<boost::optional<Exposed>, Transformed> >::type>
Chris@16:     {
Chris@16:         typedef Transformed const& type;
Chris@16:         static Transformed const& pre(boost::optional<Exposed> const& val)
Chris@16:         {
Chris@16:             return boost::get<Transformed>(val);
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     template <typename Attribute>
Chris@16:     struct transform_attribute<Attribute const, Attribute>
Chris@16:     {
Chris@16:         typedef Attribute const& type;
Chris@16:         static Attribute const& pre(Attribute const& val) { return val; }
Chris@16:         // Karma only, no post() and no fail() required
Chris@16:     };
Chris@16: 
Chris@16:     // reference types need special handling
Chris@16:     template <typename Exposed, typename Transformed>
Chris@16:     struct transform_attribute<Exposed&, Transformed>
Chris@16:       : transform_attribute<Exposed, Transformed>
Chris@16:     {};
Chris@16: 
Chris@16:     template <typename Exposed, typename Transformed>
Chris@16:     struct transform_attribute<Exposed const&, Transformed>
Chris@16:       : transform_attribute<Exposed const, Transformed>
Chris@16:     {};
Chris@16: 
Chris@16:     template <typename Attribute>
Chris@16:     struct transform_attribute<Attribute const&, Attribute>
Chris@16:       : transform_attribute<Attribute const, Attribute>
Chris@16:     {};
Chris@16: 
Chris@16:     // unused_type needs some special handling as well
Chris@16:     template <>
Chris@16:     struct transform_attribute<unused_type, unused_type>
Chris@16:     {
Chris@16:         typedef unused_type type;
Chris@16:         static unused_type pre(unused_type) { return unused; }
Chris@16:     };
Chris@16: 
Chris@16:     template <>
Chris@16:     struct transform_attribute<unused_type const, unused_type>
Chris@16:       : transform_attribute<unused_type, unused_type>
Chris@16:     {};
Chris@16: 
Chris@16:     template <typename Attribute>
Chris@16:     struct transform_attribute<unused_type, Attribute>
Chris@16:       : transform_attribute<unused_type, unused_type>
Chris@16:     {};
Chris@16: 
Chris@16:     template <typename Attribute>
Chris@16:     struct transform_attribute<unused_type const, Attribute>
Chris@16:       : transform_attribute<unused_type, unused_type>
Chris@16:     {};
Chris@16: 
Chris@16:     template <typename Attribute>
Chris@16:     struct transform_attribute<Attribute, unused_type>
Chris@16:       : transform_attribute<unused_type, unused_type>
Chris@16:     {};
Chris@16: 
Chris@16:     template <typename Attribute>
Chris@16:     struct transform_attribute<Attribute const, unused_type>
Chris@16:       : transform_attribute<unused_type, unused_type>
Chris@16:     {};
Chris@16: }}}
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: namespace boost { namespace spirit { namespace traits
Chris@16: {
Chris@16:     template <typename Exposed, typename Transformed>
Chris@16:     struct transform_attribute<Exposed, Transformed, karma::domain>
Chris@16:       : karma::transform_attribute<Exposed, Transformed>
Chris@16:     {};
Chris@16: }}}
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: