1 ///////////////////////////////////////////////////////////////////////////////
3 /// Definintion of null_context\<\>, an evaluation context for
4 /// proto::eval() that simply evaluates each child expression, doesn't
5 /// combine the results at all, and returns void.
7 // Copyright 2008 Eric Niebler. Distributed under the Boost
8 // Software License, Version 1.0. (See accompanying file
9 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
11 #ifndef BOOST_PROTO_CONTEXT_NULL_HPP_EAN_06_24_2007
12 #define BOOST_PROTO_CONTEXT_NULL_HPP_EAN_06_24_2007
14 #include <boost/preprocessor/iteration/iterate.hpp>
15 #include <boost/preprocessor/repetition/repeat.hpp>
16 #include <boost/proto/proto_fwd.hpp>
17 #include <boost/proto/eval.hpp>
18 #include <boost/proto/traits.hpp>
20 namespace boost { namespace proto { namespace context
26 , long Arity // = Expr::proto_arity_c
31 template<typename Expr, typename Context>
32 struct null_eval<Expr, Context, 0>
34 typedef void result_type;
35 void operator()(Expr &, Context &) const
39 // Additional specializations generated by the preprocessor
40 #include <boost/proto/context/detail/null_eval.hpp>
46 /// null_context::eval
48 template<typename Expr, typename ThisContext = null_context const>
50 : null_eval<Expr, ThisContext>