Chris@16: 
Chris@16: #ifndef BOOST_MPL_AUX_PUSH_FRONT_IMPL_HPP_INCLUDED
Chris@16: #define BOOST_MPL_AUX_PUSH_FRONT_IMPL_HPP_INCLUDED
Chris@16: 
Chris@16: // Copyright Aleksey Gurtovoy 2000-2008
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. 
Chris@16: // (See accompanying file LICENSE_1_0.txt or copy at 
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: // See http://www.boost.org/libs/mpl for documentation.
Chris@16: 
Chris@101: // $Id$
Chris@101: // $Date$
Chris@101: // $Revision$
Chris@16: 
Chris@16: #include <boost/mpl/push_front_fwd.hpp>
Chris@16: #include <boost/mpl/assert.hpp>
Chris@16: #include <boost/mpl/aux_/has_type.hpp>
Chris@16: #include <boost/mpl/aux_/traits_lambda_spec.hpp>
Chris@16: #include <boost/mpl/aux_/config/forwarding.hpp>
Chris@16: #include <boost/mpl/aux_/config/static_constant.hpp>
Chris@16: 
Chris@16: #include <boost/type_traits/is_same.hpp>
Chris@16: 
Chris@16: namespace boost { namespace mpl {
Chris@16: 
Chris@16: struct has_push_front_arg {};
Chris@16: 
Chris@16: // agurt 05/feb/04: no default implementation; the stub definition is needed 
Chris@16: // to enable the default 'has_push_front' implementation below
Chris@16: 
Chris@16: template< typename Tag >
Chris@16: struct push_front_impl
Chris@16: {
Chris@16:     template< typename Sequence, typename T > struct apply
Chris@16:     {
Chris@16:         // should be instantiated only in the context of 'has_push_front_impl';
Chris@16:         // if you've got an assert here, you are requesting a 'push_front' 
Chris@16:         // specialization that doesn't exist.
Chris@16:         BOOST_MPL_ASSERT_MSG(
Chris@16:               ( boost::is_same< T, has_push_front_arg >::value )
Chris@16:             , REQUESTED_PUSH_FRONT_SPECIALIZATION_FOR_SEQUENCE_DOES_NOT_EXIST
Chris@16:             , ( Sequence )
Chris@16:             );
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template< typename Tag >
Chris@16: struct has_push_front_impl
Chris@16: {
Chris@16:     template< typename Seq > struct apply
Chris@16: #if !defined(BOOST_MPL_CFG_NO_NESTED_FORWARDING)
Chris@16:         : aux::has_type< push_front< Seq, has_push_front_arg > >
Chris@16:     {
Chris@16: #else
Chris@16:     {
Chris@16:         typedef aux::has_type< push_front< Seq, has_push_front_arg > > type;
Chris@16:         BOOST_STATIC_CONSTANT(bool, value = 
Chris@16:               (aux::has_type< push_front< Seq, has_push_front_arg > >::value)
Chris@16:             );
Chris@16: #endif
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: BOOST_MPL_ALGORITM_TRAITS_LAMBDA_SPEC(2, push_front_impl)
Chris@16: BOOST_MPL_ALGORITM_TRAITS_LAMBDA_SPEC(1, has_push_front_impl)
Chris@16: 
Chris@16: }}
Chris@16: 
Chris@16: #endif // BOOST_MPL_AUX_PUSH_FRONT_IMPL_HPP_INCLUDED