units/detail/push_front_if.hpp

0001 // Boost.Units - A C++ library for zero-overhead dimensional analysis and
0002 // unit/quantity manipulation and conversion
0003 //
0004 // Copyright (C) 2003-2008 Matthias Christian Schabel
0005 // Copyright (C) 2008 Steven Watanabe
0006 //
0007 // Distributed under the Boost Software License, Version 1.0. (See
0008 // accompanying file LICENSE_1_0.txt or copy at
0009 // http://www.boost.org/LICENSE_1_0.txt)
0010
0011 #ifndef BOOST_UNITS_DETAIL_PUSH_FRONT_IF_HPP
0012 #define BOOST_UNITS_DETAIL_PUSH_FRONT_IF_HPP
0013
0014 namespace boost {
0015
0016 namespace units {
0017
0018 template<class T, class Next>
0019 struct list;
0020
0021 namespace detail {
0022
0023 template<bool>
0024 struct push_front_if;
0025
0026 template<>
0027 struct push_front_if<true> {
0028     template<class L, class T>
0029     struct apply {
0030         typedef list<T, L> type;
0031     };
0032 };
0033
0034 template<>
0035 struct push_front_if<false> {
0036     template<class L, class T>
0037     struct apply {
0038         typedef L type;
0039     };
0040 };
0041
0042 }
0043
0044 }
0045
0046 }
0047
0048 #endif