1
2#ifndef BOOST_MPL_AUX_PUSH_BACK_IMPL_HPP_INCLUDED
3#define BOOST_MPL_AUX_PUSH_BACK_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_back_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_back_arg {};
29
30// agurt 05/feb/04: no default implementation; the stub definition is needed
31// to enable the default 'has_push_back' implementation below
32template< typename Tag >
33struct push_back_impl
34{
35 template< typename Sequence, typename T > struct apply
36 {
37 // should be instantiated only in the context of 'has_push_back_impl';
38 // if you've got an assert here, you are requesting a 'push_back'
39 // specialization that doesn't exist.
40 BOOST_MPL_ASSERT_MSG(
41 ( boost::is_same< T, has_push_back_arg >::value )
42 , REQUESTED_PUSH_BACK_SPECIALIZATION_FOR_SEQUENCE_DOES_NOT_EXIST
43 , ( Sequence )
44 );
45 };
46};
47
48template< typename Tag >
49struct has_push_back_impl
50{
51 template< typename Seq > struct apply
52#if !defined(BOOST_MPL_CFG_NO_NESTED_FORWARDING)
53 : aux::has_type< push_back< Seq, has_push_back_arg > >
54 {
55#else
56 {
57 typedef aux::has_type< push_back< Seq, has_push_back_arg > > type;
58 BOOST_STATIC_CONSTANT(bool, value =
59 (aux::has_type< push_back< Seq, has_push_back_arg > >::value)
60 );
61#endif
62 };
63};
64
65BOOST_MPL_ALGORITM_TRAITS_LAMBDA_SPEC(2, push_back_impl)
66BOOST_MPL_ALGORITM_TRAITS_LAMBDA_SPEC(1, has_push_back_impl)
67
68}}
69
70#endif // BOOST_MPL_AUX_PUSH_BACK_IMPL_HPP_INCLUDED
71

source code of include/boost/mpl/aux_/push_back_impl.hpp