| #ifndef BOOST_PP_IS_ITERATING |
| /////////////////////////////////////////////////////////////////////////////// |
| /// \file call.hpp |
| /// Contains definition of the call<> transform. |
| // |
| // 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_CALL_HPP_EAN_11_02_2007 |
| #define BOOST_PROTO_TRANSFORM_CALL_HPP_EAN_11_02_2007 |
| |
| #include <boost/preprocessor/cat.hpp> |
| #include <boost/preprocessor/facilities/intercept.hpp> |
| #include <boost/preprocessor/iteration/iterate.hpp> |
| #include <boost/preprocessor/repetition/enum.hpp> |
| #include <boost/preprocessor/repetition/repeat.hpp> |
| #include <boost/preprocessor/repetition/enum_params.hpp> |
| #include <boost/preprocessor/repetition/enum_binary_params.hpp> |
| #include <boost/preprocessor/repetition/enum_trailing_params.hpp> |
| #include <boost/ref.hpp> |
| #include <boost/utility/result_of.hpp> |
| #include <boost/proto/proto_fwd.hpp> |
| #include <boost/proto/traits.hpp> |
| #include <boost/proto/transform/impl.hpp> |
| #include <boost/proto/detail/as_lvalue.hpp> |
| #include <boost/proto/detail/poly_function.hpp> |
| |
| namespace boost { namespace proto |
| { |
| /// \brief Wrap \c PrimitiveTransform so that <tt>when\<\></tt> knows |
| /// it is callable. Requires that the parameter is actually a |
| /// PrimitiveTransform. |
| /// |
| /// This form of <tt>call\<\></tt> is useful for annotating an |
| /// arbitrary PrimitiveTransform as callable when using it with |
| /// <tt>when\<\></tt>. Consider the following transform, which |
| /// is parameterized with another transform. |
| /// |
| /// \code |
| /// template<typename Grammar> |
| /// struct Foo |
| /// : when< |
| /// unary_plus<Grammar> |
| /// , Grammar(_child) // May or may not work. |
| /// > |
| /// {}; |
| /// \endcode |
| /// |
| /// The problem with the above is that <tt>when\<\></tt> may or |
| /// may not recognize \c Grammar as callable, depending on how |
| /// \c Grammar is implemented. (See <tt>is_callable\<\></tt> for |
| /// a discussion of this issue.) You can guard against |
| /// the issue by wrapping \c Grammar in <tt>call\<\></tt>, such |
| /// as: |
| /// |
| /// \code |
| /// template<typename Grammar> |
| /// struct Foo |
| /// : when< |
| /// unary_plus<Grammar> |
| /// , call<Grammar>(_child) // OK, this works |
| /// > |
| /// {}; |
| /// \endcode |
| /// |
| /// The above could also have been written as: |
| /// |
| /// \code |
| /// template<typename Grammar> |
| /// struct Foo |
| /// : when< |
| /// unary_plus<Grammar> |
| /// , call<Grammar(_child)> // OK, this works, too |
| /// > |
| /// {}; |
| /// \endcode |
| template<typename PrimitiveTransform> |
| struct call |
| : PrimitiveTransform |
| {}; |
| |
| /// \brief Either call the PolymorphicFunctionObject with 0 |
| /// arguments, or invoke the PrimitiveTransform with 3 |
| /// arguments. |
| template<typename Fun> |
| struct call<Fun()> : transform<call<Fun()> > |
| { |
| /// INTERNAL ONLY |
| template<typename Expr, typename State, typename Data, bool B> |
| struct impl2 |
| : transform_impl<Expr, State, Data> |
| { |
| typedef typename boost::tr1_result_of<Fun()>::type result_type; |
| |
| result_type operator()( |
| typename impl2::expr_param |
| , typename impl2::state_param |
| , typename impl2::data_param |
| ) const |
| { |
| return Fun()(); |
| } |
| }; |
| |
| /// INTERNAL ONLY |
| template<typename Expr, typename State, typename Data> |
| struct impl2<Expr, State, Data, true> |
| : Fun::template impl<Expr, State, Data> |
| {}; |
| |
| /// Either call the PolymorphicFunctionObject \c Fun with 0 arguments; or |
| /// invoke the PrimitiveTransform \c Fun with 3 arguments: the current |
| /// expression, state, and data. |
| /// |
| /// If \c Fun is a nullary PolymorphicFunctionObject, return <tt>Fun()()</tt>. |
| /// Otherwise, return <tt>Fun()(e, s, d)</tt>. |
| /// |
| /// \param e The current expression |
| /// \param s The current state |
| /// \param d An arbitrary data |
| |
| /// If \c Fun is a nullary PolymorphicFunctionObject, \c type is a typedef |
| /// for <tt>boost::result_of\<Fun()\>::type</tt>. Otherwise, it is |
| /// a typedef for <tt>boost::result_of\<Fun(Expr, State, Data)\>::type</tt>. |
| template<typename Expr, typename State, typename Data> |
| struct impl |
| : impl2<Expr, State, Data, is_transform<Fun>::value> |
| {}; |
| }; |
| |
| /// \brief Either call the PolymorphicFunctionObject with 1 |
| /// argument, or invoke the PrimitiveTransform with 3 |
| /// arguments. |
| template<typename Fun, typename A0> |
| struct call<Fun(A0)> : transform<call<Fun(A0)> > |
| { |
| template<typename Expr, typename State, typename Data, bool B> |
| struct impl2 |
| : transform_impl<Expr, State, Data> |
| { |
| typedef typename when<_, A0>::template impl<Expr, State, Data>::result_type a0; |
| typedef typename detail::poly_function_traits<Fun, Fun(a0)>::result_type result_type; |
| result_type operator ()( |
| typename impl2::expr_param e |
| , typename impl2::state_param s |
| , typename impl2::data_param d |
| ) const |
| { |
| return typename detail::poly_function_traits<Fun, Fun(a0)>::function_type()( |
| detail::as_lvalue(typename when<_, A0>::template impl<Expr, State, Data>()(e, s, d)) |
| ); |
| } |
| }; |
| |
| template<typename Expr, typename State, typename Data> |
| struct impl2<Expr, State, Data, true> |
| : transform_impl<Expr, State, Data> |
| { |
| typedef typename when<_, A0>::template impl<Expr, State, Data>::result_type a0; |
| typedef typename Fun::template impl<a0, State, Data>::result_type result_type; |
| result_type operator ()( |
| typename impl2::expr_param e |
| , typename impl2::state_param s |
| , typename impl2::data_param d |
| ) const |
| { |
| return typename Fun::template impl<a0, State, Data>()( |
| typename when<_, A0>::template impl<Expr, State, Data>()(e, s, d) |
| , s |
| , d |
| ); |
| } |
| }; |
| /// Let \c x be <tt>when\<_, A0\>()(e, s, d)</tt> and \c X |
| /// be the type of \c x. |
| /// If \c Fun is a unary PolymorphicFunctionObject that accepts \c x, |
| /// then \c type is a typedef for <tt>boost::result_of\<Fun(X)\>::type</tt>. |
| /// Otherwise, it is a typedef for <tt>boost::result_of\<Fun(X, State, Data)\>::type</tt>. |
| |
| /// Either call the PolymorphicFunctionObject with 1 argument: |
| /// the result of applying the \c A0 transform; or |
| /// invoke the PrimitiveTransform with 3 arguments: |
| /// result of applying the \c A0 transform, the state, and the |
| /// data. |
| /// |
| /// Let \c x be <tt>when\<_, A0\>()(e, s, d)</tt>. |
| /// If \c Fun is a unary PolymorphicFunctionObject that accepts \c x, |
| /// then return <tt>Fun()(x)</tt>. Otherwise, return |
| /// <tt>Fun()(x, s, d)</tt>. |
| /// |
| /// \param e The current expression |
| /// \param s The current state |
| /// \param d An arbitrary data |
| template<typename Expr, typename State, typename Data> |
| struct impl |
| : impl2<Expr, State, Data, is_transform<Fun>::value> |
| {}; |
| }; |
| |
| /// \brief Either call the PolymorphicFunctionObject with 2 |
| /// arguments, or invoke the PrimitiveTransform with 3 |
| /// arguments. |
| template<typename Fun, typename A0, typename A1> |
| struct call<Fun(A0, A1)> : transform<call<Fun(A0, A1)> > |
| { |
| template<typename Expr, typename State, typename Data, bool B> |
| struct impl2 |
| : transform_impl<Expr, State, Data> |
| { |
| typedef typename when<_, A0>::template impl<Expr, State, Data>::result_type a0; |
| typedef typename when<_, A1>::template impl<Expr, State, Data>::result_type a1; |
| typedef typename detail::poly_function_traits<Fun, Fun(a0, a1)>::result_type result_type; |
| result_type operator ()( |
| typename impl2::expr_param e |
| , typename impl2::state_param s |
| , typename impl2::data_param d |
| ) const |
| { |
| return typename detail::poly_function_traits<Fun, Fun(a0, a1)>::function_type()( |
| detail::as_lvalue(typename when<_, A0>::template impl<Expr, State, Data>()(e, s, d)) |
| , detail::as_lvalue(typename when<_, A1>::template impl<Expr, State, Data>()(e, s, d)) |
| ); |
| } |
| }; |
| |
| template<typename Expr, typename State, typename Data> |
| struct impl2<Expr, State, Data, true> |
| : transform_impl<Expr, State, Data> |
| { |
| typedef typename when<_, A0>::template impl<Expr, State, Data>::result_type a0; |
| typedef typename when<_, A1>::template impl<Expr, State, Data>::result_type a1; |
| typedef typename Fun::template impl<a0, a1, Data>::result_type result_type; |
| result_type operator ()( |
| typename impl2::expr_param e |
| , typename impl2::state_param s |
| , typename impl2::data_param d |
| ) const |
| { |
| return typename Fun::template impl<a0, a1, Data>()( |
| typename when<_, A0>::template impl<Expr, State, Data>()(e, s, d) |
| , typename when<_, A1>::template impl<Expr, State, Data>()(e, s, d) |
| , d |
| ); |
| } |
| }; |
| |
| /// Let \c x be <tt>when\<_, A0\>()(e, s, d)</tt> and \c X |
| /// be the type of \c x. |
| /// Let \c y be <tt>when\<_, A1\>()(e, s, d)</tt> and \c Y |
| /// be the type of \c y. |
| /// If \c Fun is a binary PolymorphicFunction object that accepts \c x |
| /// and \c y, then \c type is a typedef for |
| /// <tt>boost::result_of\<Fun(X, Y)\>::type</tt>. Otherwise, it is |
| /// a typedef for <tt>boost::result_of\<Fun(X, Y, Data)\>::type</tt>. |
| |
| /// Either call the PolymorphicFunctionObject with 2 arguments: |
| /// the result of applying the \c A0 transform, and the |
| /// result of applying the \c A1 transform; or invoke the |
| /// PrimitiveTransform with 3 arguments: the result of applying |
| /// the \c A0 transform, the result of applying the \c A1 |
| /// transform, and the data. |
| /// |
| /// Let \c x be <tt>when\<_, A0\>()(e, s, d)</tt>. |
| /// Let \c y be <tt>when\<_, A1\>()(e, s, d)</tt>. |
| /// If \c Fun is a binary PolymorphicFunction object that accepts \c x |
| /// and \c y, return <tt>Fun()(x, y)</tt>. Otherwise, return |
| /// <tt>Fun()(x, y, d)</tt>. |
| /// |
| /// \param e The current expression |
| /// \param s The current state |
| /// \param d An arbitrary data |
| template<typename Expr, typename State, typename Data> |
| struct impl |
| : impl2<Expr, State, Data, is_transform<Fun>::value> |
| {}; |
| }; |
| |
| /// \brief Call the PolymorphicFunctionObject or the |
| /// PrimitiveTransform with the current expression, state |
| /// and data, transformed according to \c A0, \c A1, and |
| /// \c A2, respectively. |
| template<typename Fun, typename A0, typename A1, typename A2> |
| struct call<Fun(A0, A1, A2)> : transform<call<Fun(A0, A1, A2)> > |
| { |
| template<typename Expr, typename State, typename Data, bool B> |
| struct impl2 |
| : transform_impl<Expr, State, Data> |
| { |
| typedef typename when<_, A0>::template impl<Expr, State, Data>::result_type a0; |
| typedef typename when<_, A1>::template impl<Expr, State, Data>::result_type a1; |
| typedef typename when<_, A2>::template impl<Expr, State, Data>::result_type a2; |
| typedef typename detail::poly_function_traits<Fun, Fun(a0, a1, a2)>::result_type result_type; |
| result_type operator ()( |
| typename impl2::expr_param e |
| , typename impl2::state_param s |
| , typename impl2::data_param d |
| ) const |
| { |
| return typename detail::poly_function_traits<Fun, Fun(a0, a1, a2)>::function_type()( |
| detail::as_lvalue(typename when<_, A0>::template impl<Expr, State, Data>()(e, s, d)) |
| , detail::as_lvalue(typename when<_, A1>::template impl<Expr, State, Data>()(e, s, d)) |
| , detail::as_lvalue(typename when<_, A2>::template impl<Expr, State, Data>()(e, s, d)) |
| ); |
| } |
| }; |
| |
| template<typename Expr, typename State, typename Data> |
| struct impl2<Expr, State, Data, true> |
| : transform_impl<Expr, State, Data> |
| { |
| typedef typename when<_, A0>::template impl<Expr, State, Data>::result_type a0; |
| typedef typename when<_, A1>::template impl<Expr, State, Data>::result_type a1; |
| typedef typename when<_, A2>::template impl<Expr, State, Data>::result_type a2; |
| typedef typename Fun::template impl<a0, a1, a2>::result_type result_type; |
| result_type operator ()( |
| typename impl2::expr_param e |
| , typename impl2::state_param s |
| , typename impl2::data_param d |
| ) const |
| { |
| return typename Fun::template impl<a0, a1, a2>()( |
| typename when<_, A0>::template impl<Expr, State, Data>()(e, s, d) |
| , typename when<_, A1>::template impl<Expr, State, Data>()(e, s, d) |
| , typename when<_, A2>::template impl<Expr, State, Data>()(e, s, d) |
| ); |
| } |
| }; |
| |
| /// Let \c x be <tt>when\<_, A0\>()(e, s, d)</tt>. |
| /// Let \c y be <tt>when\<_, A1\>()(e, s, d)</tt>. |
| /// Let \c z be <tt>when\<_, A2\>()(e, s, d)</tt>. |
| /// Return <tt>Fun()(x, y, z)</tt>. |
| /// |
| /// \param e The current expression |
| /// \param s The current state |
| /// \param d An arbitrary data |
| |
| template<typename Expr, typename State, typename Data> |
| struct impl |
| : impl2<Expr, State, Data, is_transform<Fun>::value> |
| {}; |
| }; |
| |
| #if BOOST_PROTO_MAX_ARITY > 3 |
| #define BOOST_PP_ITERATION_PARAMS_1 (3, (4, BOOST_PROTO_MAX_ARITY, <boost/proto/transform/call.hpp>)) |
| #include BOOST_PP_ITERATE() |
| #endif |
| |
| /// INTERNAL ONLY |
| /// |
| template<typename Fun> |
| struct is_callable<call<Fun> > |
| : mpl::true_ |
| {}; |
| |
| }} // namespace boost::proto |
| |
| #endif |
| |
| #else |
| |
| #define N BOOST_PP_ITERATION() |
| |
| /// \brief Call the PolymorphicFunctionObject \c Fun with the |
| /// current expression, state and data, transformed according |
| /// to \c A0 through \c AN. |
| template<typename Fun BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A)> |
| struct call<Fun(BOOST_PP_ENUM_PARAMS(N, A))> : transform<call<Fun(BOOST_PP_ENUM_PARAMS(N, A))> > |
| { |
| template<typename Expr, typename State, typename Data> |
| struct impl : transform_impl<Expr, State, Data> |
| { |
| #define M0(Z, M, DATA) \ |
| typedef \ |
| typename when<_, BOOST_PP_CAT(A, M)> \ |
| ::template impl<Expr, State, Data> \ |
| ::result_type \ |
| BOOST_PP_CAT(a, M); \ |
| /**/ |
| BOOST_PP_REPEAT(N, M0, ~) |
| #undef M0 |
| |
| typedef |
| typename detail::poly_function_traits<Fun, Fun(BOOST_PP_ENUM_PARAMS(N, a))>::result_type |
| result_type; |
| |
| /// Let \c ax be <tt>when\<_, Ax\>()(e, s, d)</tt> |
| /// for each \c x in <tt>[0,N]</tt>. |
| /// Return <tt>Fun()(a0, a1,... aN)</tt>. |
| /// |
| /// \param e The current expression |
| /// \param s The current state |
| /// \param d An arbitrary data |
| result_type operator ()( |
| typename impl::expr_param e |
| , typename impl::state_param s |
| , typename impl::data_param d |
| ) const |
| { |
| #define M0(Z, M, DATA) \ |
| detail::as_lvalue( \ |
| typename when<_, BOOST_PP_CAT(A, M)> \ |
| ::template impl<Expr, State, Data>()(e, s, d)) \ |
| /**/ |
| return typename detail::poly_function_traits<Fun, Fun(BOOST_PP_ENUM_PARAMS(N, a))>::function_type()( |
| BOOST_PP_ENUM(N, M0, ~) |
| ); |
| #undef M0 |
| } |
| }; |
| }; |
| |
| #undef N |
| |
| #endif |