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boost/proto/transform/default.hpp

#ifndef BOOST_PP_IS_ITERATING
    ///////////////////////////////////////////////////////////////////////////////
    /// \file default.hpp
    /// Contains definition of the _default transform, which gives operators their
    /// usual C++ meanings and uses Boost.Typeof to deduce return types.
    //
    //  Copyright 2008 Eric Niebler. 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_PROTO_TRANSFORM_DEFAULT_HPP_EAN_04_04_2008
    #define BOOST_PROTO_TRANSFORM_DEFAULT_HPP_EAN_04_04_2008

    #include <boost/preprocessor/iteration/iterate.hpp>
    #include <boost/preprocessor/repetition/repeat.hpp>
    #include <boost/preprocessor/repetition/enum_shifted.hpp>
    #include <boost/preprocessor/repetition/enum_shifted_params.hpp>
    #include <boost/ref.hpp>
    #include <boost/get_pointer.hpp>
    #include <boost/utility/enable_if.hpp>
    #include <boost/type_traits/is_member_pointer.hpp>
    #include <boost/type_traits/is_member_object_pointer.hpp>
    #include <boost/type_traits/is_member_function_pointer.hpp>
    #include <boost/proto/proto_fwd.hpp>
    #include <boost/proto/traits.hpp>
    #include <boost/proto/transform/impl.hpp>
    #include <boost/proto/transform/arg.hpp>
    #include <boost/proto/detail/decltype.hpp>

    namespace boost { namespace proto
    {
        template<typename Grammar /*= detail::_default*/>
        struct _default
          : transform<_default<Grammar> >
        {
            template<typename Expr, typename State, typename Data, typename Tag, long Arity>
            struct impl2;

            template<typename Expr, typename State, typename Data, typename Tag>
            struct impl2<Expr, State, Data, Tag, 0>
              : _value::impl<Expr, State, Data>
            {};

            #define BOOST_PROTO_UNARY_OP_RESULT(OP, TAG, MAKE)                                      \
            template<typename Expr, typename State, typename Data>                                  \
            struct impl2<Expr, State, Data, TAG, 1>                                                 \
              : transform_impl<Expr, State, Data>                                                   \
            {                                                                                       \
            private:                                                                                \
                typedef typename result_of::child_c<Expr, 0>::type e0;                              \
                typedef typename Grammar::template impl<e0, State, Data>::result_type r0;           \
            public:                                                                                 \
                BOOST_PROTO_DECLTYPE_(OP proto::detail::MAKE<r0>(), result_type)                    \
                result_type operator ()(                                                            \
                    typename impl2::expr_param e                                                    \
                  , typename impl2::state_param s                                                   \
                  , typename impl2::data_param d                                                    \
                ) const                                                                             \
                {                                                                                   \
                    typename Grammar::template impl<e0, State, Data> t0;                            \
                    return OP t0(proto::child_c<0>(e), s, d);                                       \
                }                                                                                   \
            };                                                                                      \
            /**/

            #define BOOST_PROTO_BINARY_OP_RESULT(OP, TAG, LMAKE, RMAKE)                             \
            template<typename Expr, typename State, typename Data>                                  \
            struct impl2<Expr, State, Data, TAG, 2>                                                 \
              : transform_impl<Expr, State, Data>                                                   \
            {                                                                                       \
            private:                                                                                \
                typedef typename result_of::child_c<Expr, 0>::type e0;                              \
                typedef typename result_of::child_c<Expr, 1>::type e1;                              \
                typedef typename Grammar::template impl<e0, State, Data>::result_type r0;           \
                typedef typename Grammar::template impl<e1, State, Data>::result_type r1;           \
            public:                                                                                 \
                BOOST_PROTO_DECLTYPE_(                                                              \
                    proto::detail::LMAKE<r0>() OP proto::detail::RMAKE<r1>()                        \
                  , result_type                                                                     \
                )                                                                                   \
                result_type operator ()(                                                            \
                    typename impl2::expr_param e                                                    \
                  , typename impl2::state_param s                                                   \
                  , typename impl2::data_param d                                                    \
                ) const                                                                             \
                {                                                                                   \
                    typename Grammar::template impl<e0, State, Data> t0;                            \
                    typename Grammar::template impl<e1, State, Data> t1;                            \
                    return t0(proto::child_c<0>(e), s, d)                                           \
                        OP t1(proto::child_c<1>(e), s, d);                                          \
                }                                                                                   \
            };                                                                                      \
            /**/

            BOOST_PROTO_UNARY_OP_RESULT(+, tag::unary_plus, make)
            BOOST_PROTO_UNARY_OP_RESULT(-, tag::negate, make)
            BOOST_PROTO_UNARY_OP_RESULT(*, tag::dereference, make)
            BOOST_PROTO_UNARY_OP_RESULT(~, tag::complement, make)
            BOOST_PROTO_UNARY_OP_RESULT(&, tag::address_of, make)
            BOOST_PROTO_UNARY_OP_RESULT(!, tag::logical_not, make)
            BOOST_PROTO_UNARY_OP_RESULT(++, tag::pre_inc, make_mutable)
            BOOST_PROTO_UNARY_OP_RESULT(--, tag::pre_dec, make_mutable)

            BOOST_PROTO_BINARY_OP_RESULT(<<, tag::shift_left, make_mutable, make)
            BOOST_PROTO_BINARY_OP_RESULT(>>, tag::shift_right, make_mutable, make_mutable)
            BOOST_PROTO_BINARY_OP_RESULT(*, tag::multiplies, make, make)
            BOOST_PROTO_BINARY_OP_RESULT(/, tag::divides, make, make)
            BOOST_PROTO_BINARY_OP_RESULT(%, tag::modulus, make, make)
            BOOST_PROTO_BINARY_OP_RESULT(+, tag::plus, make, make)
            BOOST_PROTO_BINARY_OP_RESULT(-, tag::minus, make, make)
            BOOST_PROTO_BINARY_OP_RESULT(<, tag::less, make, make)
            BOOST_PROTO_BINARY_OP_RESULT(>, tag::greater, make, make)
            BOOST_PROTO_BINARY_OP_RESULT(<=, tag::less_equal, make, make)
            BOOST_PROTO_BINARY_OP_RESULT(>=, tag::greater_equal, make, make)
            BOOST_PROTO_BINARY_OP_RESULT(==, tag::equal_to, make, make)
            BOOST_PROTO_BINARY_OP_RESULT(!=, tag::not_equal_to, make, make)
            BOOST_PROTO_BINARY_OP_RESULT(||, tag::logical_or, make, make)
            BOOST_PROTO_BINARY_OP_RESULT(&&, tag::logical_and, make, make)
            BOOST_PROTO_BINARY_OP_RESULT(&, tag::bitwise_and, make, make)
            BOOST_PROTO_BINARY_OP_RESULT(|, tag::bitwise_or, make, make)
            BOOST_PROTO_BINARY_OP_RESULT(^, tag::bitwise_xor, make, make)

            BOOST_PROTO_BINARY_OP_RESULT(=, tag::assign, make_mutable, make)
            BOOST_PROTO_BINARY_OP_RESULT(<<=, tag::shift_left_assign, make_mutable, make)
            BOOST_PROTO_BINARY_OP_RESULT(>>=, tag::shift_right_assign, make_mutable, make)
            BOOST_PROTO_BINARY_OP_RESULT(*=, tag::multiplies_assign, make_mutable, make)
            BOOST_PROTO_BINARY_OP_RESULT(/=, tag::divides_assign, make_mutable, make)
            BOOST_PROTO_BINARY_OP_RESULT(%=, tag::modulus_assign, make_mutable, make)
            BOOST_PROTO_BINARY_OP_RESULT(+=, tag::plus_assign, make_mutable, make)
            BOOST_PROTO_BINARY_OP_RESULT(-=, tag::minus_assign, make_mutable, make)
            BOOST_PROTO_BINARY_OP_RESULT(&=, tag::bitwise_and_assign, make_mutable, make)
            BOOST_PROTO_BINARY_OP_RESULT(|=, tag::bitwise_or_assign, make_mutable, make)
            BOOST_PROTO_BINARY_OP_RESULT(^=, tag::bitwise_xor_assign, make_mutable, make)

            #undef BOOST_PROTO_UNARY_OP_RESULT
            #undef BOOST_PROTO_BINARY_OP_RESULT

            /// INTERNAL ONLY
            template<typename Expr, typename State, typename Data>
            struct is_member_function_invocation
              : is_member_function_pointer<
                    typename remove_const<
                        typename remove_reference<
                            typename Grammar::template impl<
                                typename result_of::child_c<Expr, 1>::type
                              , State
                              , Data
                            >::result_type
                        >::type
                    >::type
                >
            {};

            /// INTERNAL ONLY
            template<typename Expr, typename State, typename Data, bool IsMemFunCall>
            struct memfun_impl
              : transform_impl<Expr, State, Data>
            {
            private:
                typedef typename result_of::child_c<Expr, 0>::type e0;
                typedef typename result_of::child_c<Expr, 1>::type e1;
                typedef typename Grammar::template impl<e0, State, Data>::result_type r0;
                typedef typename Grammar::template impl<e1, State, Data>::result_type r1;
            public:
                typedef typename detail::mem_ptr_fun<r0, r1>::result_type result_type;
                result_type operator ()(
                    typename memfun_impl::expr_param e
                  , typename memfun_impl::state_param s
                  , typename memfun_impl::data_param d
                ) const
                {
                    typename Grammar::template impl<e0, State, Data> t0;
                    typename Grammar::template impl<e1, State, Data> t1;
                    return detail::mem_ptr_fun<r0, r1>()(
                        t0(proto::child_c<0>(e), s, d)
                      , t1(proto::child_c<1>(e), s, d)
                    );
                }
            };

            /// INTERNAL ONLY
            template<typename Expr, typename State, typename Data>
            struct memfun_impl<Expr, State, Data, true>
              : transform_impl<Expr, State, Data>
            {
            private:
                typedef typename result_of::child_c<Expr, 0>::type e0;
                typedef typename result_of::child_c<Expr, 1>::type e1;
                typedef typename Grammar::template impl<e0, State, Data>::result_type r0;
                typedef typename Grammar::template impl<e1, State, Data>::result_type r1;
            public:
                typedef detail::memfun<r0, r1> result_type;
                result_type const operator ()(
                    typename memfun_impl::expr_param e
                  , typename memfun_impl::state_param s
                  , typename memfun_impl::data_param d
                ) const
                {
                    typename Grammar::template impl<e0, State, Data> t0;
                    typename Grammar::template impl<e1, State, Data> t1;
                    return detail::memfun<r0, r1>(
                        t0(proto::child_c<0>(e), s, d)
                      , t1(proto::child_c<1>(e), s, d)
                    );
                }
            };

            template<typename Expr, typename State, typename Data>
            struct impl2<Expr, State, Data, tag::mem_ptr, 2>
              : memfun_impl<Expr, State, Data, is_member_function_invocation<Expr, State, Data>::value>
            {};

            template<typename Expr, typename State, typename Data>
            struct impl2<Expr, State, Data, tag::post_inc, 1>
              : transform_impl<Expr, State, Data>
            {
            private:
                typedef typename result_of::child_c<Expr, 0>::type e0;
                typedef typename Grammar::template impl<e0, State, Data>::result_type r0;
            public:
                BOOST_PROTO_DECLTYPE_(proto::detail::make_mutable<r0>() ++, result_type)
                result_type operator ()(
                    typename impl2::expr_param e
                  , typename impl2::state_param s
                  , typename impl2::data_param d
                ) const
                {
                    typename Grammar::template impl<e0, State, Data> t0;
                    return t0(proto::child_c<0>(e), s, d) ++;
                }
            };

            template<typename Expr, typename State, typename Data>
            struct impl2<Expr, State, Data, tag::post_dec, 1>
              : transform_impl<Expr, State, Data>
            {
            private:
                typedef typename result_of::child_c<Expr, 0>::type e0;
                typedef typename Grammar::template impl<e0, State, Data>::result_type r0;
            public:
                BOOST_PROTO_DECLTYPE_(proto::detail::make_mutable<r0>() --, result_type)
                result_type operator ()(
                    typename impl2::expr_param e
                  , typename impl2::state_param s
                  , typename impl2::data_param d
                ) const
                {
                    typename Grammar::template impl<e0, State, Data> t0;
                    return t0(proto::child_c<0>(e), s, d) --;
                }
            };

            template<typename Expr, typename State, typename Data>
            struct impl2<Expr, State, Data, tag::subscript, 2>
              : transform_impl<Expr, State, Data>
            {
            private:
                typedef typename result_of::child_c<Expr, 0>::type e0;
                typedef typename result_of::child_c<Expr, 1>::type e1;
                typedef typename Grammar::template impl<e0, State, Data>::result_type r0;
                typedef typename Grammar::template impl<e1, State, Data>::result_type r1;
            public:
                BOOST_PROTO_DECLTYPE_(
                    proto::detail::make_subscriptable<r0>() [ proto::detail::make<r1>() ]
                  , result_type
                )
                result_type operator ()(
                    typename impl2::expr_param e
                  , typename impl2::state_param s
                  , typename impl2::data_param d
                ) const
                {
                    typename Grammar::template impl<e0, State, Data> t0;
                    typename Grammar::template impl<e1, State, Data> t1;
                    return t0(proto::child_c<0>(e), s, d) [
                           t1(proto::child_c<1>(e), s, d) ];
                }
            };

            template<typename Expr, typename State, typename Data>
            struct impl2<Expr, State, Data, tag::if_else_, 3>
              : transform_impl<Expr, State, Data>
            {
            private:
                typedef typename result_of::child_c<Expr, 0>::type e0;
                typedef typename result_of::child_c<Expr, 1>::type e1;
                typedef typename result_of::child_c<Expr, 2>::type e2;
                typedef typename Grammar::template impl<e0, State, Data>::result_type r0;
                typedef typename Grammar::template impl<e1, State, Data>::result_type r1;
                typedef typename Grammar::template impl<e2, State, Data>::result_type r2;
            public:
                BOOST_PROTO_DECLTYPE_(
                    proto::detail::make<r0>()
                  ? proto::detail::make<r1>()
                  : proto::detail::make<r2>()
                  , result_type
                )
                result_type operator ()(
                    typename impl2::expr_param e
                  , typename impl2::state_param s
                  , typename impl2::data_param d
                ) const
                {
                    typename Grammar::template impl<e0, State, Data> t0;
                    typename Grammar::template impl<e1, State, Data> t1;
                    typename Grammar::template impl<e2, State, Data> t2;
                    return t0(proto::child_c<0>(e), s, d)
                         ? t1(proto::child_c<1>(e), s, d)
                         : t2(proto::child_c<2>(e), s, d);
                }
            };

            template<typename Expr, typename State, typename Data>
            struct impl2<Expr, State, Data, tag::comma, 2>
              : transform_impl<Expr, State, Data>
            {
            private:
                typedef typename result_of::child_c<Expr, 0>::type e0;
                typedef typename result_of::child_c<Expr, 1>::type e1;
                typedef typename Grammar::template impl<e0, State, Data>::result_type r0;
                typedef typename Grammar::template impl<e1, State, Data>::result_type r1;
            public:
                typedef typename proto::detail::comma_result<r0, r1>::type result_type;
                result_type operator ()(
                    typename impl2::expr_param e
                  , typename impl2::state_param s
                  , typename impl2::data_param d
                ) const
                {
                    typename Grammar::template impl<e0, State, Data> t0;
                    typename Grammar::template impl<e1, State, Data> t1;
                    return t0(proto::child_c<0>(e), s, d)
                         , t1(proto::child_c<1>(e), s, d);
                }
            };

            #define EVAL_TYPE(Z, N, DATA)                                                           \
                typedef                                                                             \
                    typename result_of::child_c<DATA, N>::type                                      \
                BOOST_PP_CAT(e, N);                                                                 \
                typedef                                                                             \
                    typename Grammar::template impl<BOOST_PP_CAT(e, N), State, Data>::result_type   \
                BOOST_PP_CAT(r, N);                                                                 \
                /**/

            #define EVAL(Z, N, DATA)                                                                \
                typename Grammar::template impl<BOOST_PP_CAT(e, N), State, Data>()(                 \
                    proto::child_c<N>(DATA), s, d                                            \
                )                                                                                   \
                /**/

            template<typename Expr, typename State, typename Data>
            struct impl2<Expr, State, Data, tag::function, 1>
              : transform_impl<Expr, State, Data>
            {
                EVAL_TYPE(~, 0, Expr)

                typedef
                    typename proto::detail::result_of_fixup<r0>::type
                function_type;

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

                result_type operator ()(
                    typename impl2::expr_param e
                  , typename impl2::state_param s
                  , typename impl2::data_param d
                ) const
                {
                    return EVAL(~, 0, e)();
                }
            };

            template<typename Expr, typename State, typename Data>
            struct impl2<Expr, State, Data, tag::function, 2>
              : transform_impl<Expr, State, Data>
            {
                EVAL_TYPE(~, 0, Expr)
                EVAL_TYPE(~, 1, Expr)

                typedef
                    typename proto::detail::result_of_fixup<r0>::type
                function_type;

                typedef
                    typename detail::result_of_<function_type(r1)>::type
                result_type;

                result_type operator ()(
                    typename impl2::expr_param e
                  , typename impl2::state_param s
                  , typename impl2::data_param d
                ) const
                {
                    return this->invoke(
                        e
                      , s
                      , d
                      , is_member_function_pointer<function_type>()
                      , is_member_object_pointer<function_type>()
                    );
                }

            private:
                result_type invoke(
                    typename impl2::expr_param e
                  , typename impl2::state_param s
                  , typename impl2::data_param d
                  , mpl::false_
                  , mpl::false_
                ) const
                {
                    return EVAL(~, 0, e)(EVAL(~, 1, e));
                }

                result_type invoke(
                    typename impl2::expr_param e
                  , typename impl2::state_param s
                  , typename impl2::data_param d
                  , mpl::true_
                  , mpl::false_
                ) const
                {
                    BOOST_PROTO_USE_GET_POINTER();
                    typedef typename detail::classtypeof<function_type>::type class_type;
                    return (BOOST_PROTO_GET_POINTER(class_type, EVAL(~, 1, e)) ->* EVAL(~, 0, e))();
                }

                result_type invoke(
                    typename impl2::expr_param e
                  , typename impl2::state_param s
                  , typename impl2::data_param d
                  , mpl::false_
                  , mpl::true_
                ) const
                {
                    BOOST_PROTO_USE_GET_POINTER();
                    typedef typename detail::classtypeof<function_type>::type class_type;
                    return (BOOST_PROTO_GET_POINTER(class_type, EVAL(~, 1, e)) ->* EVAL(~, 0, e));
                }
            };

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

            #undef EVAL_TYPE
            #undef EVAL

            template<typename Expr, typename State, typename Data>
            struct impl
              : impl2<
                    Expr
                  , State
                  , Data
                  , typename transform_impl<Expr, State, Data>::expr::proto_tag
                  , transform_impl<Expr, State, Data>::expr::proto_arity_c
                >
            {};
        };

        template<typename Grammar>
        struct is_callable<_default<Grammar> >
          : mpl::true_
        {};

        namespace detail
        {
            // Loopy indirection that allows proto::_default<> to be
            // used without specifying a Grammar argument.
            struct _default
              : proto::_default<>
            {};
        }

    }}

    #endif

#else

    #define N BOOST_PP_ITERATION()

        template<typename Expr, typename State, typename Data>
        struct impl2<Expr, State, Data, tag::function, N>
          : transform_impl<Expr, State, Data>
        {
            BOOST_PP_REPEAT(N, EVAL_TYPE, Expr)

            typedef
                typename proto::detail::result_of_fixup<r0>::type
            function_type;

            typedef
                typename boost::result_of<
                    function_type(BOOST_PP_ENUM_SHIFTED_PARAMS(N, r))
                >::type
            result_type;

            result_type operator ()(
                typename impl2::expr_param e
              , typename impl2::state_param s
              , typename impl2::data_param d
            ) const
            {
                return this->invoke(e, s, d, is_member_function_pointer<function_type>());
            }

        private:
            result_type invoke(
                typename impl2::expr_param e
              , typename impl2::state_param s
              , typename impl2::data_param d
              , mpl::false_
            ) const
            {
                return EVAL(~, 0, e)(BOOST_PP_ENUM_SHIFTED(N, EVAL, e));
            }

            result_type invoke(
                typename impl2::expr_param e
              , typename impl2::state_param s
              , typename impl2::data_param d
              , mpl::true_
            ) const
            {
                #define M0(Z, M, e) BOOST_PP_COMMA_IF(BOOST_PP_SUB(M, 2)) EVAL(Z, M, e)
                BOOST_PROTO_USE_GET_POINTER();
                typedef typename detail::classtypeof<function_type>::type class_type;
                return (BOOST_PROTO_GET_POINTER(class_type, EVAL(~, 1, e)) ->* EVAL(~, 0, e))(
                    BOOST_PP_REPEAT_FROM_TO(2, N, M0, e)
                );
                #undef M0
            }
        };

    #undef N

#endif