boost/type_traits/disjunction.hpp
/* Copyright 2020 Glen Joseph Fernandes (glenjofe@gmail.com) Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) */ #ifndef BOOST_TT_DISJUNCTION_HPP_INCLUDED #define BOOST_TT_DISJUNCTION_HPP_INCLUDED #include <boost/type_traits/conditional.hpp> #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) #include <boost/type_traits/integral_constant.hpp> #endif namespace boost { #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) template<class...> struct disjunction : false_type { }; template<class T> struct disjunction<T> : T { }; template<class T, class... U> struct disjunction<T, U...> : conditional<bool(T::value), T, disjunction<U...> >::type { }; #else template<class T, class U> struct disjunction : conditional<bool(T::value), T, U>::type { }; #endif } /* boost */ #endif