1 /*============================================================================= 2 Copyright (c) 2001-2014 Joel de Guzman 3 Copyright (c) 2013 Agustin Berge 4 5 Distributed under the Boost Software License, Version 1.0. (See accompanying 6 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 7 ==============================================================================*/ 8 #if !defined(BOOST_SPIRIT_X3_SFINAE_MAY_20_2013_0840AM) 9 #define BOOST_SPIRIT_X3_SFINAE_MAY_20_2013_0840AM 10 11 namespace boost { namespace spirit { namespace x3 12 { 13 template <typename Expr, typename T = void> 14 struct disable_if_substitution_failure 15 { 16 typedef T type; 17 }; 18 19 template <typename Expr, typename T> 20 struct lazy_disable_if_substitution_failure 21 { 22 typedef typename T::type type; 23 }; 24 }}} 25 26 #endif 27