1
2#ifndef BOOST_MPL_AUX_FRONT_IMPL_HPP_INCLUDED
3#define BOOST_MPL_AUX_FRONT_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/front_fwd.hpp>
18#include <boost/mpl/begin_end.hpp>
19#include <boost/mpl/deref.hpp>
20#include <boost/mpl/aux_/traits_lambda_spec.hpp>
21
22namespace boost { namespace mpl {
23
24// default implementation; conrete sequences might override it by
25// specializing either the 'front_impl' or the primary 'front' template
26
27template< typename Tag >
28struct front_impl
29{
30 template< typename Sequence > struct apply
31 {
32 typedef typename begin<Sequence>::type iter_;
33 typedef typename deref<iter_>::type type;
34 };
35};
36
37BOOST_MPL_ALGORITM_TRAITS_LAMBDA_SPEC(1,front_impl)
38
39}}
40
41#endif // BOOST_MPL_AUX_FRONT_IMPL_HPP_INCLUDED
42

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