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/*=============================================================================
Copyright (c) 2001-2014 Joel de Guzman
Copyright (c) 2001-2011 Hartmut Kaiser
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
=============================================================================*/
#if !defined(SPIRIT_X3_DETAIL_ATTRIBUTES_APR_18_2010_0458PM)
#define SPIRIT_X3_DETAIL_ATTRIBUTES_APR_18_2010_0458PM
#include <boost/spirit/home/x3/support/traits/transform_attribute.hpp>
#include <boost/spirit/home/x3/support/traits/move_to.hpp>
///////////////////////////////////////////////////////////////////////////////
namespace boost { namespace spirit { namespace x3
{
struct parser_id;
template <typename Exposed, typename Transformed>
struct default_transform_attribute
{
typedef Transformed type;
static Transformed pre(Exposed&) { return Transformed(); }
static void post(Exposed& val, Transformed& attr)
{
traits::move_to(attr, val);
}
};
// handle case where no transformation is required as the types are the same
template <typename Attribute>
struct default_transform_attribute<Attribute, Attribute>
{
typedef Attribute& type;
static Attribute& pre(Attribute& val) { return val; }
static void post(Attribute&, Attribute const&) {}
};
// main specialization for x3
template <typename Exposed, typename Transformed, typename Enable = void>
struct transform_attribute
: default_transform_attribute<Exposed, Transformed> {};
// reference types need special handling
template <typename Attribute>
struct transform_attribute<Attribute&, Attribute>
{
typedef Attribute& type;
static Attribute& pre(Attribute& val) { return val; }
static void post(Attribute&, Attribute const&) {}
};
// unused_type needs some special handling as well
template <>
struct transform_attribute<unused_type, unused_type>
{
typedef unused_type type;
static unused_type pre(unused_type) { return unused; }
static void post(unused_type, unused_type) {}
};
template <>
struct transform_attribute<unused_type const, unused_type>
: transform_attribute<unused_type, unused_type> {};
template <typename Attribute>
struct transform_attribute<unused_type, Attribute>
: transform_attribute<unused_type, unused_type> {};
template <typename Attribute>
struct transform_attribute<unused_type const, Attribute>
: transform_attribute<unused_type, unused_type> {};
template <typename Attribute>
struct transform_attribute<Attribute, unused_type>
: transform_attribute<unused_type, unused_type> {};
template <typename Attribute>
struct transform_attribute<Attribute const, unused_type>
: transform_attribute<unused_type, unused_type> {};
}}}
///////////////////////////////////////////////////////////////////////////////
namespace boost { namespace spirit { namespace x3 { namespace traits
{
template <typename Exposed, typename Transformed>
struct transform_attribute<Exposed, Transformed, x3::parser_id>
: x3::transform_attribute<Exposed, Transformed> {};
template <typename Exposed, typename Transformed>
struct transform_attribute<Exposed&, Transformed, x3::parser_id>
: transform_attribute<Exposed, Transformed, x3::parser_id> {};
template <typename Attribute>
struct transform_attribute<Attribute&, Attribute, x3::parser_id>
: x3::transform_attribute<Attribute&, Attribute> {};
///////////////////////////////////////////////////////////////////////////
template <typename Exposed, typename Transformed>
void post_transform(Exposed& dest, Transformed&& attr)
{
return transform_attribute<Exposed, Transformed, x3::parser_id>::post(dest, attr);
}
}}}}
#endif
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