#ifndef BOOST_METAPARSE_V1_ACCEPT_WHEN_HPP #define BOOST_METAPARSE_V1_ACCEPT_WHEN_HPP // Copyright Abel Sinkovics (abel@sinkovics.hu) 2009 - 2010. // 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) #include <boost/metaparse/v1/get_result.hpp> #include <boost/metaparse/v1/reject.hpp> #include <boost/metaparse/v1/is_error.hpp> #include <boost/mpl/if.hpp> #include <boost/mpl/eval_if.hpp> namespace boost { namespace metaparse { namespace v1 { template <class P, class Pred, class Msg> struct accept_when { private: struct unchecked { template <class S, class Pos> struct apply : boost::mpl::eval_if< typename Pred::template apply< typename get_result<typename P::template apply<S, Pos> >::type >::type, typename P::template apply<S, Pos>, reject<Msg, Pos> > {}; }; public: typedef accept_when type; template <class S, class Pos> struct apply : boost::mpl::if_< is_error<typename P::template apply<S, Pos> >, P, unchecked >::type::template apply< S, Pos > {}; }; } } } #endif