| /*============================================================================= |
| Copyright (c) 2001-2007 Joel de Guzman |
| |
| 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) |
| ==============================================================================*/ |
| #if !defined(BOOST_PP_IS_ITERATING) |
| #if !defined(PHOENIX_CORE_DETAIL_FUNCTION_EVAL_HPP) |
| #define PHOENIX_CORE_DETAIL_FUNCTION_EVAL_HPP |
| |
| #include <boost/preprocessor/iterate.hpp> |
| #include <boost/preprocessor/enum.hpp> |
| #include <boost/preprocessor/repeat.hpp> |
| #include <boost/preprocessor/dec.hpp> |
| #include <boost/mpl/eval_if.hpp> |
| #include <boost/mpl/find.hpp> |
| #include <boost/mpl/identity.hpp> |
| #include <boost/type_traits/is_same.hpp> |
| #include <boost/type_traits/remove_reference.hpp> |
| |
| // we assume that mpl::vectorN, where N = PHOENIX_COMPOSITE_LIMIT |
| // is included already. |
| |
| namespace boost { namespace phoenix { namespace detail |
| { |
| template <int N> |
| struct function_eval; |
| |
| template <> |
| struct function_eval<0> |
| { |
| template <typename Env, typename F> |
| struct result |
| { |
| typedef typename |
| remove_reference< |
| typename F::template result<Env>::type |
| >::type |
| fn; |
| typedef typename fn::result_type type; |
| }; |
| |
| template <typename RT, typename Env, typename F> |
| static RT |
| eval(Env const& env, F const& f) |
| { |
| return f.eval(env)(); |
| } |
| }; |
| |
| template <typename T> |
| T& help_rvalue_deduction(T& x) |
| { |
| return x; |
| } |
| |
| template <typename T> |
| T const& help_rvalue_deduction(T const& x) |
| { |
| return x; |
| } |
| |
| // When we call f(_0, _1...) we remove the reference when deducing f's |
| // return type. $$$ Explain why $$$ |
| |
| #define PHOENIX_GET_ARG(z, n, data) \ |
| typedef typename \ |
| remove_reference< \ |
| typename BOOST_PP_CAT(A, n)::template result<Env>::type \ |
| >::type \ |
| BOOST_PP_CAT(a, n); |
| |
| #define PHOENIX_EVAL_ARG(z, n, data) \ |
| help_rvalue_deduction(BOOST_PP_CAT(_, n).eval(env)) |
| |
| #define BOOST_PP_ITERATION_PARAMS_1 \ |
| (3, (1, BOOST_PP_DEC(PHOENIX_COMPOSITE_LIMIT), \ |
| "boost/spirit/home/phoenix/core/detail/function_eval.hpp")) |
| #include BOOST_PP_ITERATE() |
| |
| }}} // namespace boost::phoenix::detail |
| |
| #undef PHOENIX_GET_ARG |
| #undef PHOENIX_EVAL_ARG |
| #endif |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // |
| // Preprocessor vertical repetition code |
| // |
| /////////////////////////////////////////////////////////////////////////////// |
| #else // defined(BOOST_PP_IS_ITERATING) |
| |
| #define N BOOST_PP_ITERATION() |
| |
| template <> |
| struct function_eval<N> |
| { |
| template <typename Env, typename F |
| , BOOST_PP_ENUM_PARAMS(N, typename A)> |
| struct result |
| { |
| typedef typename |
| remove_reference< |
| typename F::template result<Env>::type |
| >::type |
| fn; |
| BOOST_PP_REPEAT(N, PHOENIX_GET_ARG, _) |
| |
| typedef BOOST_PP_CAT(mpl::vector, N) |
| <BOOST_PP_ENUM_PARAMS(N, a)> |
| args; |
| |
| typedef typename |
| fn::template result<BOOST_PP_ENUM_PARAMS(N, a)> |
| function_apply; |
| |
| typedef typename |
| mpl::eval_if< |
| is_same< |
| typename mpl::find<args, fusion::void_>::type |
| , typename mpl::end<args>::type> |
| , function_apply |
| , mpl::identity<fusion::void_> |
| >::type |
| type; |
| }; |
| |
| template <typename RT, typename Env, typename F |
| , BOOST_PP_ENUM_PARAMS(N, typename A)> |
| static RT |
| eval(Env const& env, F const& f |
| , BOOST_PP_ENUM_BINARY_PARAMS(N, A, & _)) |
| { |
| return f.eval(env)(BOOST_PP_ENUM(N, PHOENIX_EVAL_ARG, _)); |
| } |
| }; |
| |
| #undef N |
| #endif // defined(BOOST_PP_IS_ITERATING) |
| |
| |