| #ifndef BOOST_PP_IS_ITERATING | |
| /////////////////////////////////////////////////////////////////////////////// | |
| /// \file make.hpp | |
| /// Contains definition of the make<> 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_MAKE_HPP_EAN_12_02_2007 | |
| #define BOOST_PROTO_TRANSFORM_MAKE_HPP_EAN_12_02_2007 | |
| #include <boost/detail/workaround.hpp> | |
| #include <boost/preprocessor/repetition/enum.hpp> | |
| #include <boost/preprocessor/repetition/enum_params.hpp> | |
| #include <boost/preprocessor/repetition/enum_trailing_params.hpp> | |
| #include <boost/preprocessor/repetition/enum_binary_params.hpp> | |
| #include <boost/preprocessor/repetition/enum_params_with_a_default.hpp> | |
| #include <boost/preprocessor/repetition/repeat_from_to.hpp> | |
| #include <boost/preprocessor/facilities/intercept.hpp> | |
| #include <boost/preprocessor/cat.hpp> | |
| #include <boost/preprocessor/iteration/iterate.hpp> | |
| #include <boost/preprocessor/selection/max.hpp> | |
| #include <boost/preprocessor/arithmetic/inc.hpp> | |
| #include <boost/mpl/and.hpp> | |
| #include <boost/mpl/aux_/has_type.hpp> | |
| #include <boost/mpl/aux_/template_arity.hpp> | |
| #include <boost/mpl/aux_/lambda_arity_param.hpp> | |
| #include <boost/utility/result_of.hpp> | |
| #include <boost/proto/proto_fwd.hpp> | |
| #include <boost/proto/traits.hpp> | |
| #include <boost/proto/args.hpp> | |
| #include <boost/proto/transform/impl.hpp> | |
| #include <boost/proto/detail/as_lvalue.hpp> | |
| #include <boost/proto/detail/ignore_unused.hpp> | |
| namespace boost { namespace proto | |
| { | |
| namespace detail | |
| { | |
| template<typename T> | |
| struct is_applyable | |
| : mpl::and_<is_callable<T>, is_transform<T> > | |
| {}; | |
| template<typename T, bool HasType = mpl::aux::has_type<T>::value> | |
| struct nested_type | |
| { | |
| typedef typename T::type type; | |
| }; | |
| template<typename T> | |
| struct nested_type<T, false> | |
| { | |
| typedef T type; | |
| }; | |
| template<typename T, bool Applied> | |
| struct nested_type_if | |
| { | |
| typedef T type; | |
| static bool const applied = false; | |
| }; | |
| template<typename T> | |
| struct nested_type_if<T, true> | |
| : nested_type<T> | |
| { | |
| static bool const applied = true; | |
| }; | |
| template< | |
| typename R | |
| , typename Expr, typename State, typename Data | |
| BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(long Arity = mpl::aux::template_arity<R>::value) | |
| > | |
| struct make_ | |
| { | |
| typedef R type; | |
| static bool const applied = false; | |
| }; | |
| template< | |
| typename R | |
| , typename Expr, typename State, typename Data | |
| , bool IsApplyable = is_applyable<R>::value | |
| > | |
| struct make_if_ | |
| : make_<R, Expr, State, Data> | |
| {}; | |
| template<typename R, typename Expr, typename State, typename Data> | |
| struct make_if_<R, Expr, State, Data, true> | |
| : uncvref<typename when<_, R>::template impl<Expr, State, Data>::result_type> | |
| { | |
| static bool const applied = true; | |
| }; | |
| #if BOOST_WORKAROUND(__GNUC__, == 3) || (__GNUC__ == 4 && __GNUC_MINOR__ == 0) | |
| // work around GCC bug | |
| template<typename Tag, typename Args, long N, typename Expr, typename State, typename Data> | |
| struct make_if_<proto::expr<Tag, Args, N>, Expr, State, Data, false> | |
| { | |
| typedef proto::expr<Tag, Args, N> type; | |
| static bool const applied = false; | |
| }; | |
| // work around GCC bug | |
| template<typename Tag, typename Args, long N, typename Expr, typename State, typename Data> | |
| struct make_if_<proto::basic_expr<Tag, Args, N>, Expr, State, Data, false> | |
| { | |
| typedef proto::basic_expr<Tag, Args, N> type; | |
| static bool const applied = false; | |
| }; | |
| #endif | |
| template<typename Type, bool IsAggregate = is_aggregate<Type>::value> | |
| struct construct_ | |
| { | |
| typedef Type result_type; | |
| Type operator ()() const | |
| { | |
| return Type(); | |
| } | |
| #define TMP(Z, N, DATA) \ | |
| template<BOOST_PP_ENUM_PARAMS_Z(Z, N, typename A)> \ | |
| Type operator ()(BOOST_PP_ENUM_BINARY_PARAMS_Z(Z, N, A, &a)) const \ | |
| { \ | |
| return Type(BOOST_PP_ENUM_PARAMS_Z(Z, N, a)); \ | |
| } | |
| BOOST_PP_REPEAT_FROM_TO(1, BOOST_PP_INC(BOOST_PROTO_MAX_ARITY), TMP, ~) | |
| #undef TMP | |
| }; | |
| template<typename Type> | |
| struct construct_<Type, true> | |
| { | |
| typedef Type result_type; | |
| Type operator ()() const | |
| { | |
| return Type(); | |
| } | |
| #define TMP(Z, N, DATA) \ | |
| template<BOOST_PP_ENUM_PARAMS_Z(Z, N, typename A)> \ | |
| Type operator ()(BOOST_PP_ENUM_BINARY_PARAMS_Z(Z, N, A, &a)) const \ | |
| { \ | |
| Type that = {BOOST_PP_ENUM_PARAMS_Z(Z, N, a)}; \ | |
| return that; \ | |
| } | |
| BOOST_PP_REPEAT_FROM_TO(1, BOOST_PP_INC(BOOST_PROTO_MAX_ARITY), TMP, ~) | |
| #undef TMP | |
| }; | |
| #define TMP(Z, N, DATA) \ | |
| template<typename Type BOOST_PP_ENUM_TRAILING_PARAMS_Z(Z, N, typename A)> \ | |
| Type construct(BOOST_PP_ENUM_BINARY_PARAMS_Z(Z, N, A, &a)) \ | |
| { \ | |
| return construct_<Type>()(BOOST_PP_ENUM_PARAMS_Z(Z, N, a)); \ | |
| } | |
| BOOST_PP_REPEAT(BOOST_PROTO_MAX_ARITY, TMP, ~) | |
| #undef TMP | |
| } | |
| /// \brief A PrimitiveTransform which prevents another PrimitiveTransform | |
| /// from being applied in an \c ObjectTransform. | |
| /// | |
| /// When building higher order transforms with <tt>make\<\></tt> or | |
| /// <tt>lazy\<\></tt>, you sometimes would like to build types that | |
| /// are parameterized with Proto transforms. In such lambda-style | |
| /// transforms, Proto will unhelpfully find all nested transforms | |
| /// and apply them, even if you don't want them to be applied. Consider | |
| /// the following transform, which will replace the \c _ in | |
| /// <tt>Bar<_>()</tt> with <tt>proto::terminal\<int\>::type</tt>: | |
| /// | |
| /// \code | |
| /// template<typename T> | |
| /// struct Bar | |
| /// {}; | |
| /// | |
| /// struct Foo | |
| /// : proto::when<_, Bar<_>() > | |
| /// {}; | |
| /// | |
| /// proto::terminal<int>::type i = {0}; | |
| /// | |
| /// int main() | |
| /// { | |
| /// Foo()(i); | |
| /// std::cout << typeid(Foo()(i)).name() << std::endl; | |
| /// } | |
| /// \endcode | |
| /// | |
| /// If you actually wanted to default-construct an object of type | |
| /// <tt>Bar\<_\></tt>, you would have to protect the \c _ to prevent | |
| /// it from being applied. You can use <tt>proto::protect\<\></tt> | |
| /// as follows: | |
| /// | |
| /// \code | |
| /// // OK: replace anything with Bar<_>() | |
| /// struct Foo | |
| /// : proto::when<_, Bar<protect<_> >() > | |
| /// {}; | |
| /// \endcode | |
| template<typename PrimitiveTransform> | |
| struct protect : transform<protect<PrimitiveTransform> > | |
| { | |
| template<typename, typename, typename> | |
| struct impl | |
| { | |
| typedef PrimitiveTransform result_type; | |
| }; | |
| }; | |
| /// \brief A PrimitiveTransform which computes a type by evaluating any | |
| /// nested transforms and then constructs an object of that type. | |
| /// | |
| /// The <tt>make\<\></tt> transform checks to see if \c Object is a template. | |
| /// If it is, the template type is disassembled to find nested transforms. | |
| /// Proto considers the following types to represent transforms: | |
| /// | |
| /// \li Function types | |
| /// \li Function pointer types | |
| /// \li Types for which <tt>proto::is_callable\< type \>::value</tt> is \c true | |
| /// | |
| /// <tt>boost::result_of\<make\<T\<X0,X1,...\> \>(Expr, State, Data)\>::type</tt> | |
| /// is evaluated as follows. For each \c X in <tt>X0,X1,...</tt>, do: | |
| /// | |
| /// \li If \c X is a template like <tt>U\<Y0,Y1,...\></tt>, then let <tt>X'</tt> | |
| /// be <tt>boost::result_of\<make\<U\<Y0,Y1,...\> \>(Expr, State, Data)\>::type</tt> | |
| /// (which evaluates this procedure recursively). Note whether any | |
| /// substitutions took place during this operation. | |
| /// \li Otherwise, if \c X is a transform, then let <tt>X'</tt> be | |
| /// <tt>boost::result_of\<when\<_, X\>(Expr, State, Data)\>::type</tt>. | |
| /// Note that a substitution took place. | |
| /// \li Otherwise, let <tt>X'</tt> be \c X, and note that no substitution | |
| /// took place. | |
| /// \li If any substitutions took place in any of the above steps and | |
| /// <tt>T\<X0',X1',...\></tt> has a nested <tt>::type</tt> typedef, | |
| /// the result type is <tt>T\<X0',X1',...\>::type</tt>. | |
| /// \li Otherwise, the result type is <tt>T\<X0',X1',...\></tt>. | |
| /// | |
| /// Note that <tt>when\<\></tt> is implemented in terms of <tt>call\<\></tt> | |
| /// and <tt>make\<\></tt>, so the above procedure is evaluated recursively. | |
| template<typename Object> | |
| struct make : transform<make<Object> > | |
| { | |
| template<typename Expr, typename State, typename Data> | |
| struct impl : transform_impl<Expr, State, Data> | |
| { | |
| typedef typename detail::make_if_<Object, Expr, State, Data>::type result_type; | |
| /// \return <tt>result_type()</tt> | |
| result_type operator ()( | |
| typename impl::expr_param | |
| , typename impl::state_param | |
| , typename impl::data_param | |
| ) const | |
| { | |
| return result_type(); | |
| } | |
| }; | |
| }; | |
| #define BOOST_PP_ITERATION_PARAMS_1 (3, (0, BOOST_PROTO_MAX_ARITY, <boost/proto/transform/make.hpp>)) | |
| #include BOOST_PP_ITERATE() | |
| /// INTERNAL ONLY | |
| /// | |
| template<typename Object> | |
| struct is_callable<make<Object> > | |
| : mpl::true_ | |
| {}; | |
| /// INTERNAL ONLY | |
| /// | |
| template<typename PrimitiveTransform> | |
| struct is_callable<protect<PrimitiveTransform> > | |
| : mpl::true_ | |
| {}; | |
| }} | |
| #endif | |
| #else | |
| #define N BOOST_PP_ITERATION() | |
| namespace detail | |
| { | |
| #if N > 0 | |
| #define TMP0(Z, M, DATA) make_if_<BOOST_PP_CAT(A, M), Expr, State, Data> | |
| #define TMP1(Z, M, DATA) typename TMP0(Z, M, DATA) ::type | |
| #define TMP2(Z, M, DATA) TMP0(Z, M, DATA) ::applied || | |
| template< | |
| template<BOOST_PP_ENUM_PARAMS(N, typename BOOST_PP_INTERCEPT)> class R | |
| BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A) | |
| , typename Expr, typename State, typename Data | |
| > | |
| struct make_< | |
| R<BOOST_PP_ENUM_PARAMS(N, A)> | |
| , Expr, State, Data | |
| BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(N) | |
| > | |
| : nested_type_if<R<BOOST_PP_ENUM(N, TMP1, ~)>, (BOOST_PP_REPEAT(N, TMP2, ~) false)> | |
| {}; | |
| template< | |
| template<BOOST_PP_ENUM_PARAMS(N, typename BOOST_PP_INTERCEPT)> class R | |
| BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A) | |
| , typename Expr, typename State, typename Data | |
| > | |
| struct make_< | |
| noinvoke<R<BOOST_PP_ENUM_PARAMS(N, A)> > | |
| , Expr, State, Data | |
| BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(1) | |
| > | |
| { | |
| typedef R<BOOST_PP_ENUM(N, TMP1, ~)> type; | |
| static bool const applied = true; | |
| }; | |
| #undef TMP0 | |
| #undef TMP1 | |
| #undef TMP2 | |
| #endif | |
| template<typename R BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A)> | |
| struct is_applyable<R(BOOST_PP_ENUM_PARAMS(N, A))> | |
| : mpl::true_ | |
| {}; | |
| template<typename R BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A)> | |
| struct is_applyable<R(*)(BOOST_PP_ENUM_PARAMS(N, A))> | |
| : mpl::true_ | |
| {}; | |
| template<typename T, typename A> | |
| struct construct_<proto::expr<T, A, N>, true> | |
| { | |
| typedef proto::expr<T, A, N> result_type; | |
| template<BOOST_PP_ENUM_PARAMS(BOOST_PP_MAX(N, 1), typename A)> | |
| result_type operator ()(BOOST_PP_ENUM_BINARY_PARAMS(BOOST_PP_MAX(N, 1), A, &a)) const | |
| { | |
| return result_type::make(BOOST_PP_ENUM_PARAMS(BOOST_PP_MAX(N, 1), a)); | |
| } | |
| }; | |
| template<typename T, typename A> | |
| struct construct_<proto::basic_expr<T, A, N>, true> | |
| { | |
| typedef proto::basic_expr<T, A, N> result_type; | |
| template<BOOST_PP_ENUM_PARAMS(BOOST_PP_MAX(N, 1), typename A)> | |
| result_type operator ()(BOOST_PP_ENUM_BINARY_PARAMS(BOOST_PP_MAX(N, 1), A, &a)) const | |
| { | |
| return result_type::make(BOOST_PP_ENUM_PARAMS(BOOST_PP_MAX(N, 1), a)); | |
| } | |
| }; | |
| } | |
| /// \brief A PrimitiveTransform which computes a type by evaluating any | |
| /// nested transforms and then constructs an object of that type with the | |
| /// current expression, state and data, transformed according | |
| /// to \c A0 through \c AN. | |
| template<typename Object BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A)> | |
| struct make<Object(BOOST_PP_ENUM_PARAMS(N, A))> | |
| : transform<make<Object(BOOST_PP_ENUM_PARAMS(N, A))> > | |
| { | |
| template<typename Expr, typename State, typename Data> | |
| struct impl : transform_impl<Expr, State, Data> | |
| { | |
| /// \brief <tt>boost::result_of\<make\<Object\>(Expr, State, Data)\>::type</tt> | |
| typedef typename detail::make_if_<Object, Expr, State, Data>::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>result_type(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 | |
| { | |
| proto::detail::ignore_unused(e); | |
| proto::detail::ignore_unused(s); | |
| proto::detail::ignore_unused(d); | |
| return detail::construct<result_type>( | |
| #define TMP(Z, M, DATA) \ | |
| detail::as_lvalue( \ | |
| typename when<_, BOOST_PP_CAT(A, M)> \ | |
| ::template impl<Expr, State, Data>()(e, s, d) \ | |
| ) | |
| BOOST_PP_ENUM(N, TMP, DATA) | |
| #undef TMP | |
| ); | |
| } | |
| }; | |
| }; | |
| #if BOOST_WORKAROUND(__GNUC__, == 3) || (__GNUC__ == 4 && __GNUC_MINOR__ == 0) | |
| // work around GCC bug | |
| template<typename Tag, typename Args, long Arity BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A)> | |
| struct make<proto::expr<Tag, Args, Arity>(BOOST_PP_ENUM_PARAMS(N, A))> | |
| : transform<make<proto::expr<Tag, Args, Arity>(BOOST_PP_ENUM_PARAMS(N, A))> > | |
| { | |
| template<typename Expr, typename State, typename Data> | |
| struct impl : transform_impl<Expr, State, Data> | |
| { | |
| typedef proto::expr<Tag, Args, Arity> result_type; | |
| result_type operator ()( | |
| typename impl::expr_param e | |
| , typename impl::state_param s | |
| , typename impl::data_param d | |
| ) const | |
| { | |
| return proto::expr<Tag, Args, Arity>::make( | |
| #define TMP(Z, M, DATA) \ | |
| detail::as_lvalue( \ | |
| typename when<_, BOOST_PP_CAT(A, M)> \ | |
| ::template impl<Expr, State, Data>()(e, s, d) \ | |
| ) | |
| BOOST_PP_ENUM(N, TMP, DATA) | |
| #undef TMP | |
| ); | |
| } | |
| }; | |
| }; | |
| template<typename Tag, typename Args, long Arity BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A)> | |
| struct make<proto::basic_expr<Tag, Args, Arity>(BOOST_PP_ENUM_PARAMS(N, A))> | |
| : transform<make<proto::basic_expr<Tag, Args, Arity>(BOOST_PP_ENUM_PARAMS(N, A))> > | |
| { | |
| template<typename Expr, typename State, typename Data> | |
| struct impl : transform_impl<Expr, State, Data> | |
| { | |
| typedef proto::basic_expr<Tag, Args, Arity> result_type; | |
| result_type operator ()( | |
| typename impl::expr_param e | |
| , typename impl::state_param s | |
| , typename impl::data_param d | |
| ) const | |
| { | |
| return proto::basic_expr<Tag, Args, Arity>::make( | |
| #define TMP(Z, M, DATA) \ | |
| detail::as_lvalue( \ | |
| typename when<_, BOOST_PP_CAT(A, M)> \ | |
| ::template impl<Expr, State, Data>()(e, s, d) \ | |
| ) | |
| BOOST_PP_ENUM(N, TMP, DATA) | |
| #undef TMP | |
| ); | |
| } | |
| }; | |
| }; | |
| #endif | |
| #undef N | |
| #endif |