boost/mpl/identity.hpp

0001
0002 #ifndef BOOST_MPL_IDENTITY_HPP_INCLUDED
0003 #define BOOST_MPL_IDENTITY_HPP_INCLUDED
0004
0005 // Copyright Aleksey Gurtovoy 2000-2004
0006 //
0007 // Distributed under the Boost Software License, Version 1.0.
0008 // (See accompanying file LICENSE_1_0.txt or copy at
0009 // http://www.boost.org/LICENSE_1_0.txt)
0010 //
0011 // See http://www.boost.org/libs/mpl for documentation.
0012
0013 // $Id$
0014 // $Date$
0015 // $Revision$
0016
0017 #include <boost/mpl/aux_/na_spec.hpp>
0018 #include <boost/mpl/aux_/lambda_support.hpp>
0019
0020 namespace boost { namespace mpl {
0021
0022 template<
0023       typename BOOST_MPL_AUX_NA_PARAM(T)
0024     >
0025 struct identity
0026 {
0027     typedef T type;
0028     BOOST_MPL_AUX_LAMBDA_SUPPORT(1, identity, (T))
0029 };
0030
0031 template<
0032       typename BOOST_MPL_AUX_NA_PARAM(T)
0033     >
0034 struct make_identity
0035 {
0036     typedef identity<T> type;
0037     BOOST_MPL_AUX_LAMBDA_SUPPORT(1, make_identity, (T))
0038 };
0039
0040 BOOST_MPL_AUX_NA_SPEC_NO_ETI(1, identity)
0041 BOOST_MPL_AUX_NA_SPEC_NO_ETI(1, make_identity)
0042
0043 }}
0044
0045 #endif // BOOST_MPL_IDENTITY_HPP_INCLUDED