default.hpp

来自「Boost provides free peer-reviewed portab」· HPP 代码 · 共 435 行 · 第 1/2 页

            };

            // Handle post-decrement specially.
            template<typename Expr, typename Context>
            struct default_eval<Expr, Context, proto::tag::post_dec, 1>
            {
            private:
                typedef typename proto::result_of::child_c<Expr, 0>::type e0;
                typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0;
            public:
                BOOST_PROTO_DECLTYPE_(proto::detail::make_mutable<r0>() --, result_type)
                result_type operator ()(Expr &expr, Context &ctx) const
                {
                    return proto::eval(proto::child_c<0>(expr), ctx) --;
                }
            };

            // Handle subscript specially.
            template<typename Expr, typename Context>
            struct default_eval<Expr, Context, proto::tag::subscript, 2>
            {
            private:
                typedef typename proto::result_of::child_c<Expr, 0>::type e0;
                typedef typename proto::result_of::child_c<Expr, 1>::type e1;
                typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0;
                typedef typename proto::result_of::eval<UNREF(e1), Context>::type r1;
            public:
                BOOST_PROTO_DECLTYPE_(proto::detail::make_subscriptable<r0>()[proto::detail::make<r1>()], result_type)
                result_type operator ()(Expr &expr, Context &ctx) const
                {
                    return proto::eval(proto::child_c<0>(expr), ctx)[proto::eval(proto::child_c<1>(expr), ctx)];
                }
            };

            // Handle if_else_ specially.
            template<typename Expr, typename Context>
            struct default_eval<Expr, Context, proto::tag::if_else_, 3>
            {
            private:
                typedef typename proto::result_of::child_c<Expr, 0>::type e0;
                typedef typename proto::result_of::child_c<Expr, 1>::type e1;
                typedef typename proto::result_of::child_c<Expr, 2>::type e2;
                typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0;
                typedef typename proto::result_of::eval<UNREF(e1), Context>::type r1;
                typedef typename proto::result_of::eval<UNREF(e2), Context>::type r2;
            public:
                BOOST_PROTO_DECLTYPE_(
                    proto::detail::make<r0>()
                  ? proto::detail::make<r1>()
                  : proto::detail::make<r2>()
                  , result_type
                )
                result_type operator ()(Expr &expr, Context &ctx) const
                {
                    return proto::eval(proto::child_c<0>(expr), ctx)
                         ? proto::eval(proto::child_c<1>(expr), ctx)
                         : proto::eval(proto::child_c<2>(expr), ctx);
                }
            };

            // Handle comma specially.
            template<typename Expr, typename Context>
            struct default_eval<Expr, Context, proto::tag::comma, 2>
            {
            private:
                typedef typename proto::result_of::child_c<Expr, 0>::type e0;
                typedef typename proto::result_of::child_c<Expr, 1>::type e1;
                typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0;
                typedef typename proto::result_of::eval<UNREF(e1), Context>::type r1;
            public:
                typedef typename proto::detail::comma_result<r0, r1>::type result_type;
                result_type operator ()(Expr &expr, Context &ctx) const
                {
                    return proto::eval(proto::child_c<0>(expr), ctx), proto::eval(proto::child_c<1>(expr), ctx);
                }
            };

            // Handle function specially
            #define EVAL_TYPE(Z, N, DATA)                                                           \
                typename proto::result_of::eval<                                                    \
                    typename remove_reference<                                                      \
                        typename proto::result_of::child_c<DATA, N>::type                           \
                    >::type                                                                         \
                  , Context                                                                         \
                >::type                                                                             \
                /**/

            #define EVAL(Z, N, DATA)                                                                \
                proto::eval(proto::child_c<N>(DATA), context)                                       \
                /**/

            template<typename Expr, typename Context>
            struct default_eval<Expr, Context, proto::tag::function, 1>
            {
                typedef
                    typename proto::detail::result_of_fixup<EVAL_TYPE(~, 0, Expr)>::type
                function_type;

                typedef
                    typename boost::result_of<function_type()>::type
                result_type;

                result_type operator ()(Expr &expr, Context &context) const
                {
                    return EVAL(~, 0, expr)();
                }
            };

            template<typename Expr, typename Context>
            struct default_eval<Expr, Context, proto::tag::function, 2>
            {
                typedef
                    typename proto::detail::result_of_fixup<EVAL_TYPE(~, 0, Expr)>::type
                function_type;

                typedef
                    typename detail::result_of_<function_type(EVAL_TYPE(~, 1, Expr))>::type
                result_type;

                result_type operator ()(Expr &expr, Context &context) const
                {
                    return this->invoke(
                        expr
                      , context
                      , is_member_function_pointer<function_type>()
                      , is_member_object_pointer<function_type>()
                    );
                }

            private:
                result_type invoke(Expr &expr, Context &context, mpl::false_, mpl::false_) const
                {
                    return EVAL(~, 0, expr)(EVAL(~, 1, expr));
                }

                result_type invoke(Expr &expr, Context &context, mpl::true_, mpl::false_) const
                {
                    using namespace detail::get_pointer_;
                    return (get_pointer(EVAL(~, 1, expr)) ->* EVAL(~, 0, expr))();
                }

                result_type invoke(Expr &expr, Context &context, mpl::false_, mpl::true_) const
                {
                    using namespace detail::get_pointer_;
                    return (get_pointer(EVAL(~, 1, expr)) ->* EVAL(~, 0, expr));
                }
            };

            #define BOOST_PP_ITERATION_PARAMS_1 (3, (3, BOOST_PROTO_MAX_ARITY, <boost/proto/context/default.hpp>))
            #include BOOST_PP_ITERATE()

            #undef EVAL_TYPE
            #undef EVAL

            /// default_context
            ///
            struct default_context
            {
                /// default_context::eval
                ///
                template<typename Expr, typename ThisContext = default_context const>
                struct eval
                  : default_eval<Expr, ThisContext>
                {};
            };

        } // namespace context

    }} // namespace boost::proto

    #undef UNREF

    #endif

#else

    #define N BOOST_PP_ITERATION()

        template<typename Expr, typename Context>
        struct default_eval<Expr, Context, proto::tag::function, N>
        {
            typedef
                typename proto::detail::result_of_fixup<EVAL_TYPE(~, 0, Expr)>::type
            function_type;

            typedef
                typename boost::result_of<
                    function_type(BOOST_PP_ENUM_SHIFTED(N, EVAL_TYPE, Expr))
                >::type
            result_type;

            result_type operator ()(Expr &expr, Context &context) const
            {
                return this->invoke(expr, context, is_member_function_pointer<function_type>());
            }

        private:
            result_type invoke(Expr &expr, Context &context, mpl::false_) const
            {
                return EVAL(~, 0, expr)(BOOST_PP_ENUM_SHIFTED(N, EVAL, expr));
            }

            result_type invoke(Expr &expr, Context &context, mpl::true_) const
            {
                #define M0(Z, M, expr) BOOST_PP_COMMA_IF(BOOST_PP_SUB(M, 2)) EVAL(Z, M, expr)
                using namespace detail::get_pointer_;
                return (get_pointer(EVAL(~, 1, expr)) ->* EVAL(~, 0, expr))(
                    BOOST_PP_REPEAT_FROM_TO(2, N, M0, expr)
                );
                #undef M0
            }
        };

    #undef N

#endif