1 
2 #ifndef BOOST_MPL_INSERT_IMPL_HPP_INCLUDED
3 #define BOOST_MPL_INSERT_IMPL_HPP_INCLUDED
4 
5 // Copyright Aleksey Gurtovoy 2000-2004
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/reverse_fold.hpp>
18 #include <boost/mpl/iterator_range.hpp>
19 #include <boost/mpl/clear.hpp>
20 #include <boost/mpl/push_front.hpp>
21 #include <boost/mpl/aux_/na_spec.hpp>
22 #include <boost/mpl/aux_/traits_lambda_spec.hpp>
23 #include <boost/type_traits/is_same.hpp>
24 
25 namespace boost { namespace mpl {
26 
27 // default implementation; conrete sequences might override it by
28 // specializing either the 'insert_impl' or the primary 'insert' template
29 
30 template< typename Tag >
31 struct insert_impl
32 {
33     template<
34           typename Sequence
35         , typename Pos
36         , typename T
37         >
38     struct apply
39     {
40         typedef iterator_range<
41               typename begin<Sequence>::type
42             , Pos
43             > first_half_;
44 
45         typedef iterator_range<
46               Pos
47             , typename end<Sequence>::type
48             > second_half_;
49 
50         typedef typename reverse_fold<
51               second_half_
52             , typename clear<Sequence>::type
53             , push_front<_,_>
54             >::type half_sequence_;
55 
56         typedef typename reverse_fold<
57               first_half_
58             , typename push_front<half_sequence_,T>::type
59             , push_front<_,_>
60             >::type type;
61     };
62 };
63 
64 BOOST_MPL_ALGORITM_TRAITS_LAMBDA_SPEC(3,insert_impl)
65 
66 }}
67 
68 #endif // BOOST_MPL_INSERT_IMPL_HPP_INCLUDED
69