1
2#ifndef BOOST_MPL_AUX_PUSH_FRONT_IMPL_HPP_INCLUDED
3#define BOOST_MPL_AUX_PUSH_FRONT_IMPL_HPP_INCLUDED
4
5// Copyright Aleksey Gurtovoy 2000-2008
6//
7// Distributed under the Boost Software License, Version 1.0.
8// (See accompanying file LICENSE_1_0.txt or copy at
9// http://www.boost.org/LICENSE_1_0.txt)
10//
11// See http://www.boost.org/libs/mpl for documentation.
12
13// $Id$
14// $Date$
15// $Revision$
16
17#include <boost/mpl/push_front_fwd.hpp>
18#include <boost/mpl/assert.hpp>
19#include <boost/mpl/aux_/has_type.hpp>
20#include <boost/mpl/aux_/traits_lambda_spec.hpp>
21#include <boost/mpl/aux_/config/forwarding.hpp>
22#include <boost/mpl/aux_/config/static_constant.hpp>
23
24#include <boost/type_traits/is_same.hpp>
25
26namespace boost { namespace mpl {
27
28struct has_push_front_arg {};
29
30// agurt 05/feb/04: no default implementation; the stub definition is needed
31// to enable the default 'has_push_front' implementation below
32
33template< typename Tag >
34struct push_front_impl
35{
36 template< typename Sequence, typename T > struct apply
37 {
38 // should be instantiated only in the context of 'has_push_front_impl';
39 // if you've got an assert here, you are requesting a 'push_front'
40 // specialization that doesn't exist.
41 BOOST_MPL_ASSERT_MSG(
42 ( boost::is_same< T, has_push_front_arg >::value )
43 , REQUESTED_PUSH_FRONT_SPECIALIZATION_FOR_SEQUENCE_DOES_NOT_EXIST
44 , ( Sequence )
45 );
46 };
47};
48
49template< typename Tag >
50struct has_push_front_impl
51{
52 template< typename Seq > struct apply
53#if !defined(BOOST_MPL_CFG_NO_NESTED_FORWARDING)
54 : aux::has_type< push_front< Seq, has_push_front_arg > >
55 {
56#else
57 {
58 typedef aux::has_type< push_front< Seq, has_push_front_arg > > type;
59 BOOST_STATIC_CONSTANT(bool, value =
60 (aux::has_type< push_front< Seq, has_push_front_arg > >::value)
61 );
62#endif
63 };
64};
65
66BOOST_MPL_ALGORITM_TRAITS_LAMBDA_SPEC(2, push_front_impl)
67BOOST_MPL_ALGORITM_TRAITS_LAMBDA_SPEC(1, has_push_front_impl)
68
69}}
70
71#endif // BOOST_MPL_AUX_PUSH_FRONT_IMPL_HPP_INCLUDED
72