boost/proto/traits.hpp
/////////////////////////////////////////////////////////////////////////////// /// \file traits.hpp /// Contains definitions for child\<\>, child_c\<\>, left\<\>, /// right\<\>, tag_of\<\>, and the helper functions child(), child_c(), /// value(), left() and right(). // // 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_ARG_TRAITS_HPP_EAN_04_01_2005 #define BOOST_PROTO_ARG_TRAITS_HPP_EAN_04_01_2005 #include <boost/config.hpp> #include <boost/detail/workaround.hpp> #include <boost/preprocessor/iteration/iterate.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/repeat.hpp> #include <boost/preprocessor/repetition/repeat_from_to.hpp> #include <boost/preprocessor/facilities/intercept.hpp> #include <boost/preprocessor/arithmetic/sub.hpp> #include <boost/static_assert.hpp> #include <boost/mpl/bool.hpp> #include <boost/proto/detail/template_arity.hpp> #include <boost/type_traits/is_pod.hpp> #include <boost/type_traits/is_same.hpp> #include <boost/type_traits/add_const.hpp> #include <boost/proto/proto_fwd.hpp> #include <boost/proto/args.hpp> #include <boost/proto/domain.hpp> #include <boost/proto/transform/pass_through.hpp> #if BOOST_WORKAROUND( BOOST_MSVC, >= 1400 ) #pragma warning(push) #pragma warning(disable: 4180) // warning C4180: qualifier applied to function type has no meaning; ignored #endif namespace boost { namespace proto { namespace detail { template<typename T, typename Void = void> struct if_vararg {}; template<typename T> struct if_vararg<T, typename T::proto_is_vararg_> : T {}; template<typename T, typename Void = void> struct is_callable2_ : mpl::false_ {}; template<typename T> struct is_callable2_<T, typename T::proto_is_callable_> : mpl::true_ {}; template<typename T BOOST_PROTO_TEMPLATE_ARITY_PARAM(long Arity = boost::proto::detail::template_arity<T>::value)> struct is_callable_ : is_callable2_<T> {}; } /// \brief Boolean metafunction which detects whether a type is /// a callable function object type or not. /// /// <tt>is_callable\<\></tt> is used by the <tt>when\<\></tt> transform /// to determine whether a function type <tt>R(A1,A2,...AN)</tt> is a /// callable transform or an object transform. (The former are evaluated /// using <tt>call\<\></tt> and the later with <tt>make\<\></tt>.) If /// <tt>is_callable\<R\>::value</tt> is \c true, the function type is /// a callable transform; otherwise, it is an object transform. /// /// Unless specialized for a type \c T, <tt>is_callable\<T\>::value</tt> /// is computed as follows: /// /// \li If \c T is a template type <tt>X\<Y0,Y1,...YN\></tt>, where all \c Yx /// are types for \c x in <tt>[0,N]</tt>, <tt>is_callable\<T\>::value</tt> /// is <tt>is_same\<YN, proto::callable\>::value</tt>. /// \li If \c T has a nested type \c proto_is_callable_ that is a typedef /// for \c void, <tt>is_callable\<T\>::value</tt> is \c true. (Note: this is /// the case for any type that derives from \c proto::callable.) /// \li Otherwise, <tt>is_callable\<T\>::value</tt> is \c false. template<typename T> struct is_callable : proto::detail::is_callable_<T> {}; /// INTERNAL ONLY /// template<> struct is_callable<proto::_> : mpl::true_ {}; /// INTERNAL ONLY /// template<> struct is_callable<proto::callable> : mpl::false_ {}; /// INTERNAL ONLY /// template<typename PrimitiveTransform, typename X> struct is_callable<proto::transform<PrimitiveTransform, X> > : mpl::false_ {}; #if BOOST_WORKAROUND(__GNUC__, == 3) || (__GNUC__ == 4 && __GNUC_MINOR__ == 0) // work around GCC bug template<typename Tag, typename Args, long N> struct is_callable<proto::expr<Tag, Args, N> > : mpl::false_ {}; // work around GCC bug template<typename Tag, typename Args, long N> struct is_callable<proto::basic_expr<Tag, Args, N> > : mpl::false_ {}; #endif namespace detail { template<typename T, typename Void /*= void*/> struct is_transform_ : mpl::false_ {}; template<typename T> struct is_transform_<T, typename T::proto_is_transform_> : mpl::true_ {}; } /// \brief Boolean metafunction which detects whether a type is /// a PrimitiveTransform type or not. /// /// <tt>is_transform\<\></tt> is used by the <tt>call\<\></tt> transform /// to determine whether the function types <tt>R()</tt>, <tt>R(A1)</tt>, /// and <tt>R(A1, A2)</tt> should be passed the expression, state and data /// parameters (as needed). /// /// Unless specialized for a type \c T, <tt>is_transform\<T\>::value</tt> /// is computed as follows: /// /// \li If \c T has a nested type \c proto_is_transform_ that is a typedef /// for \c void, <tt>is_transform\<T\>::value</tt> is \c true. (Note: this is /// the case for any type that derives from an instantiation of \c proto::transform.) /// \li Otherwise, <tt>is_transform\<T\>::value</tt> is \c false. template<typename T> struct is_transform : proto::detail::is_transform_<T> {}; namespace detail { template<typename T, typename Void /*= void*/> struct is_aggregate_ : is_pod<T> {}; template<typename Tag, typename Args, long N> struct is_aggregate_<proto::expr<Tag, Args, N>, void> : mpl::true_ {}; template<typename Tag, typename Args, long N> struct is_aggregate_<proto::basic_expr<Tag, Args, N>, void> : mpl::true_ {}; template<typename T> struct is_aggregate_<T, typename T::proto_is_aggregate_> : mpl::true_ {}; } /// \brief A Boolean metafunction that indicates whether a type requires /// aggregate initialization. /// /// <tt>is_aggregate\<\></tt> is used by the <tt>make\<\></tt> transform /// to determine how to construct an object of some type \c T, given some /// initialization arguments <tt>a0,a1,...aN</tt>. /// If <tt>is_aggregate\<T\>::value</tt> is \c true, then an object of /// type T will be initialized as <tt>T t = {a0,a1,...aN};</tt>. Otherwise, /// it will be initialized as <tt>T t(a0,a1,...aN)</tt>. template<typename T> struct is_aggregate : proto::detail::is_aggregate_<T> {}; /// \brief A Boolean metafunction that indicates whether a given /// type \c T is a Proto expression type. /// /// If \c T has a nested type \c proto_is_expr_ that is a typedef /// for \c void, <tt>is_expr\<T\>::value</tt> is \c true. (Note, this /// is the case for <tt>proto::expr\<\></tt>, any type that is derived /// from <tt>proto::extends\<\></tt> or that uses the /// <tt>BOOST_PROTO_BASIC_EXTENDS()</tt> macro.) Otherwise, /// <tt>is_expr\<T\>::value</tt> is \c false. template<typename T, typename Void /* = void*/> struct is_expr : mpl::false_ {}; /// \brief A Boolean metafunction that indicates whether a given /// type \c T is a Proto expression type. /// /// If \c T has a nested type \c proto_is_expr_ that is a typedef /// for \c void, <tt>is_expr\<T\>::value</tt> is \c true. (Note, this /// is the case for <tt>proto::expr\<\></tt>, any type that is derived /// from <tt>proto::extends\<\></tt> or that uses the /// <tt>BOOST_PROTO_BASIC_EXTENDS()</tt> macro.) Otherwise, /// <tt>is_expr\<T\>::value</tt> is \c false. template<typename T> struct is_expr<T, typename T::proto_is_expr_> : mpl::true_ {}; template<typename T> struct is_expr<T &, void> : is_expr<T> {}; /// \brief A metafunction that returns the tag type of a /// Proto expression. template<typename Expr> struct tag_of { typedef typename Expr::proto_tag type; }; template<typename Expr> struct tag_of<Expr &> { typedef typename Expr::proto_tag type; }; /// \brief A metafunction that returns the arity of a /// Proto expression. template<typename Expr> struct arity_of : Expr::proto_arity {}; template<typename Expr> struct arity_of<Expr &> : Expr::proto_arity {}; namespace result_of { /// \brief A metafunction that computes the return type of the \c as_expr() /// function. template<typename T, typename Domain /*= default_domain*/> struct as_expr { typedef typename Domain::template as_expr<T>::result_type type; }; /// \brief A metafunction that computes the return type of the \c as_child() /// function. template<typename T, typename Domain /*= default_domain*/> struct as_child { typedef typename Domain::template as_child<T>::result_type type; }; /// \brief A metafunction that returns the type of the Nth child /// of a Proto expression, where N is an MPL Integral Constant. /// /// <tt>result_of::child\<Expr, N\></tt> is equivalent to /// <tt>result_of::child_c\<Expr, N::value\></tt>. template<typename Expr, typename N /* = mpl::long_<0>*/> struct child : child_c<Expr, N::value> {}; /// \brief A metafunction that returns the type of the value /// of a terminal Proto expression. /// template<typename Expr> struct value { /// Verify that we are actually operating on a terminal BOOST_STATIC_ASSERT(0 == Expr::proto_arity_c); /// The raw type of the Nth child as it is stored within /// \c Expr. This may be a value or a reference typedef typename Expr::proto_child0 value_type; /// The "value" type of the child, suitable for storage by value, /// computed as follows: /// \li <tt>T const(&)[N]</tt> becomes <tt>T[N]</tt> /// \li <tt>T[N]</tt> becomes <tt>T[N]</tt> /// \li <tt>T(&)[N]</tt> becomes <tt>T[N]</tt> /// \li <tt>R(&)(A0,...)</tt> becomes <tt>R(&)(A0,...)</tt> /// \li <tt>T const &</tt> becomes <tt>T</tt> /// \li <tt>T &</tt> becomes <tt>T</tt> /// \li <tt>T</tt> becomes <tt>T</tt> typedef typename detail::term_traits<typename Expr::proto_child0>::value_type type; }; template<typename Expr> struct value<Expr &> { /// Verify that we are actually operating on a terminal BOOST_STATIC_ASSERT(0 == Expr::proto_arity_c); /// The raw type of the Nth child as it is stored within /// \c Expr. This may be a value or a reference typedef typename Expr::proto_child0 value_type; /// The "reference" type of the child, suitable for storage by /// reference, computed as follows: /// \li <tt>T const(&)[N]</tt> becomes <tt>T const(&)[N]</tt> /// \li <tt>T[N]</tt> becomes <tt>T(&)[N]</tt> /// \li <tt>T(&)[N]</tt> becomes <tt>T(&)[N]</tt> /// \li <tt>R(&)(A0,...)</tt> becomes <tt>R(&)(A0,...)</tt> /// \li <tt>T const &</tt> becomes <tt>T const &</tt> /// \li <tt>T &</tt> becomes <tt>T &</tt> /// \li <tt>T</tt> becomes <tt>T &</tt> typedef typename detail::term_traits<typename Expr::proto_child0>::reference type; }; template<typename Expr> struct value<Expr const &> { /// Verify that we are actually operating on a terminal BOOST_STATIC_ASSERT(0 == Expr::proto_arity_c); /// The raw type of the Nth child as it is stored within /// \c Expr. This may be a value or a reference typedef typename Expr::proto_child0 value_type; /// The "const reference" type of the child, suitable for storage by /// const reference, computed as follows: /// \li <tt>T const(&)[N]</tt> becomes <tt>T const(&)[N]</tt> /// \li <tt>T[N]</tt> becomes <tt>T const(&)[N]</tt> /// \li <tt>T(&)[N]</tt> becomes <tt>T(&)[N]</tt> /// \li <tt>R(&)(A0,...)</tt> becomes <tt>R(&)(A0,...)</tt> /// \li <tt>T const &</tt> becomes <tt>T const &</tt> /// \li <tt>T &</tt> becomes <tt>T &</tt> /// \li <tt>T</tt> becomes <tt>T const &</tt> typedef typename detail::term_traits<typename Expr::proto_child0>::const_reference type; }; /// \brief A metafunction that returns the type of the left child /// of a binary Proto expression. /// /// <tt>result_of::left\<Expr\></tt> is equivalent to /// <tt>result_of::child_c\<Expr, 0\></tt>. template<typename Expr> struct left : child_c<Expr, 0> {}; /// \brief A metafunction that returns the type of the right child /// of a binary Proto expression. /// /// <tt>result_of::right\<Expr\></tt> is equivalent to /// <tt>result_of::child_c\<Expr, 1\></tt>. template<typename Expr> struct right : child_c<Expr, 1> {}; } // namespace result_of /// \brief A metafunction for generating terminal expression types, /// a grammar element for matching terminal expressions, and a /// PrimitiveTransform that returns the current expression unchanged. template<typename T> struct terminal : proto::transform<terminal<T>, int> { typedef proto::expr<proto::tag::terminal, term<T>, 0> type; typedef proto::basic_expr<proto::tag::terminal, term<T>, 0> proto_grammar; template<typename Expr, typename State, typename Data> struct impl : transform_impl<Expr, State, Data> { typedef Expr result_type; /// \param e The current expression /// \pre <tt>matches\<Expr, terminal\<T\> \>::value</tt> is \c true. /// \return \c e /// \throw nothrow #ifdef BOOST_PROTO_STRICT_RESULT_OF result_type #else typename impl::expr_param #endif operator ()( typename impl::expr_param e , typename impl::state_param , typename impl::data_param ) const { return e; } }; /// INTERNAL ONLY typedef proto::tag::terminal proto_tag; /// INTERNAL ONLY typedef T proto_child0; }; /// \brief A metafunction for generating ternary conditional expression types, /// a grammar element for matching ternary conditional expressions, and a /// PrimitiveTransform that dispatches to the <tt>pass_through\<\></tt> /// transform. template<typename T, typename U, typename V> struct if_else_ : proto::transform<if_else_<T, U, V>, int> { typedef proto::expr<proto::tag::if_else_, list3<T, U, V>, 3> type; typedef proto::basic_expr<proto::tag::if_else_, list3<T, U, V>, 3> proto_grammar; template<typename Expr, typename State, typename Data> struct impl : detail::pass_through_impl<if_else_, Expr, State, Data> {}; /// INTERNAL ONLY typedef proto::tag::if_else_ proto_tag; /// INTERNAL ONLY typedef T proto_child0; /// INTERNAL ONLY typedef U proto_child1; /// INTERNAL ONLY typedef V proto_child2; }; /// \brief A metafunction for generating nullary expression types with a /// specified tag type, /// a grammar element for matching nullary expressions, and a /// PrimitiveTransform that returns the current expression unchanged. /// /// Use <tt>nullary_expr\<_, _\></tt> as a grammar element to match any /// nullary expression. template<typename Tag, typename T> struct nullary_expr : proto::transform<nullary_expr<Tag, T>, int> { typedef proto::expr<Tag, term<T>, 0> type; typedef proto::basic_expr<Tag, term<T>, 0> proto_grammar; template<typename Expr, typename State, typename Data> struct impl : transform_impl<Expr, State, Data> { typedef Expr result_type; /// \param e The current expression /// \pre <tt>matches\<Expr, nullary_expr\<Tag, T\> \>::value</tt> is \c true. /// \return \c e /// \throw nothrow #ifdef BOOST_PROTO_STRICT_RESULT_OF result_type #else typename impl::expr_param #endif operator ()( typename impl::expr_param e , typename impl::state_param , typename impl::data_param ) const { return e; } }; /// INTERNAL ONLY typedef Tag proto_tag; /// INTERNAL ONLY typedef T proto_child0; }; /// \brief A metafunction for generating unary expression types with a /// specified tag type, /// a grammar element for matching unary expressions, and a /// PrimitiveTransform that dispatches to the <tt>pass_through\<\></tt> /// transform. /// /// Use <tt>unary_expr\<_, _\></tt> as a grammar element to match any /// unary expression. template<typename Tag, typename T> struct unary_expr : proto::transform<unary_expr<Tag, T>, int> { typedef proto::expr<Tag, list1<T>, 1> type; typedef proto::basic_expr<Tag, list1<T>, 1> proto_grammar; template<typename Expr, typename State, typename Data> struct impl : detail::pass_through_impl<unary_expr, Expr, State, Data> {}; /// INTERNAL ONLY typedef Tag proto_tag; /// INTERNAL ONLY typedef T proto_child0; }; /// \brief A metafunction for generating binary expression types with a /// specified tag type, /// a grammar element for matching binary expressions, and a /// PrimitiveTransform that dispatches to the <tt>pass_through\<\></tt> /// transform. /// /// Use <tt>binary_expr\<_, _, _\></tt> as a grammar element to match any /// binary expression. template<typename Tag, typename T, typename U> struct binary_expr : proto::transform<binary_expr<Tag, T, U>, int> { typedef proto::expr<Tag, list2<T, U>, 2> type; typedef proto::basic_expr<Tag, list2<T, U>, 2> proto_grammar; template<typename Expr, typename State, typename Data> struct impl : detail::pass_through_impl<binary_expr, Expr, State, Data> {}; /// INTERNAL ONLY typedef Tag proto_tag; /// INTERNAL ONLY typedef T proto_child0; /// INTERNAL ONLY typedef U proto_child1; }; #define BOOST_PROTO_DEFINE_UNARY_METAFUNCTION(Op) \ template<typename T> \ struct Op \ : proto::transform<Op<T>, int> \ { \ typedef proto::expr<proto::tag::Op, list1<T>, 1> type; \ typedef proto::basic_expr<proto::tag::Op, list1<T>, 1> proto_grammar; \ \ template<typename Expr, typename State, typename Data> \ struct impl \ : detail::pass_through_impl<Op, Expr, State, Data> \ {}; \ \ typedef proto::tag::Op proto_tag; \ typedef T proto_child0; \ }; \ /**/ #define BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(Op) \ template<typename T, typename U> \ struct Op \ : proto::transform<Op<T, U>, int> \ { \ typedef proto::expr<proto::tag::Op, list2<T, U>, 2> type; \ typedef proto::basic_expr<proto::tag::Op, list2<T, U>, 2> proto_grammar; \ \ template<typename Expr, typename State, typename Data> \ struct impl \ : detail::pass_through_impl<Op, Expr, State, Data> \ {}; \ \ typedef proto::tag::Op proto_tag; \ typedef T proto_child0; \ typedef U proto_child1; \ }; \ /**/ BOOST_PROTO_DEFINE_UNARY_METAFUNCTION(unary_plus) BOOST_PROTO_DEFINE_UNARY_METAFUNCTION(negate) BOOST_PROTO_DEFINE_UNARY_METAFUNCTION(dereference) BOOST_PROTO_DEFINE_UNARY_METAFUNCTION(complement) BOOST_PROTO_DEFINE_UNARY_METAFUNCTION(address_of) BOOST_PROTO_DEFINE_UNARY_METAFUNCTION(logical_not) BOOST_PROTO_DEFINE_UNARY_METAFUNCTION(pre_inc) BOOST_PROTO_DEFINE_UNARY_METAFUNCTION(pre_dec) BOOST_PROTO_DEFINE_UNARY_METAFUNCTION(post_inc) BOOST_PROTO_DEFINE_UNARY_METAFUNCTION(post_dec) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(shift_left) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(shift_right) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(multiplies) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(divides) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(modulus) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(plus) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(minus) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(less) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(greater) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(less_equal) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(greater_equal) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(equal_to) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(not_equal_to) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(logical_or) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(logical_and) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(bitwise_or) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(bitwise_and) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(bitwise_xor) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(comma) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(mem_ptr) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(assign) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(shift_left_assign) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(shift_right_assign) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(multiplies_assign) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(divides_assign) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(modulus_assign) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(plus_assign) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(minus_assign) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(bitwise_or_assign) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(bitwise_and_assign) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(bitwise_xor_assign) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(subscript) BOOST_PROTO_DEFINE_BINARY_METAFUNCTION(member) #undef BOOST_PROTO_DEFINE_UNARY_METAFUNCTION #undef BOOST_PROTO_DEFINE_BINARY_METAFUNCTION #include <boost/proto/detail/traits.hpp> namespace functional { /// \brief A callable PolymorphicFunctionObject that is /// equivalent to the \c as_expr() function. template<typename Domain /* = default_domain*/> struct as_expr { BOOST_PROTO_CALLABLE() template<typename Sig> struct result; template<typename This, typename T> struct result<This(T)> { typedef typename Domain::template as_expr<T>::result_type type; }; template<typename This, typename T> struct result<This(T &)> { typedef typename Domain::template as_expr<T>::result_type type; }; /// \brief Wrap an object in a Proto terminal if it isn't a /// Proto expression already. /// \param t The object to wrap. /// \return <tt>proto::as_expr\<Domain\>(t)</tt> template<typename T> typename add_const<typename result<as_expr(T &)>::type>::type operator ()(T &t) const { return typename Domain::template as_expr<T>()(t); } /// \overload /// template<typename T> typename add_const<typename result<as_expr(T const &)>::type>::type operator ()(T const &t) const { return typename Domain::template as_expr<T const>()(t); } #if BOOST_WORKAROUND(BOOST_MSVC, == 1310) template<typename T, std::size_t N_> typename add_const<typename result<as_expr(T (&)[N_])>::type>::type operator ()(T (&t)[N_]) const { return typename Domain::template as_expr<T[N_]>()(t); } template<typename T, std::size_t N_> typename add_const<typename result<as_expr(T const (&)[N_])>::type>::type operator ()(T const (&t)[N_]) const { return typename Domain::template as_expr<T const[N_]>()(t); } #endif }; /// \brief A callable PolymorphicFunctionObject that is /// equivalent to the \c as_child() function. template<typename Domain /* = default_domain*/> struct as_child { BOOST_PROTO_CALLABLE() template<typename Sig> struct result; template<typename This, typename T> struct result<This(T)> { typedef typename Domain::template as_child<T>::result_type type; }; template<typename This, typename T> struct result<This(T &)> { typedef typename Domain::template as_child<T>::result_type type; }; /// \brief Wrap an object in a Proto terminal if it isn't a /// Proto expression already. /// \param t The object to wrap. /// \return <tt>proto::as_child\<Domain\>(t)</tt> template<typename T> typename add_const<typename result<as_child(T &)>::type>::type operator ()(T &t) const { return typename Domain::template as_child<T>()(t); } /// \overload /// template<typename T> typename add_const<typename result<as_child(T const &)>::type>::type operator ()(T const &t) const { return typename Domain::template as_child<T const>()(t); } }; /// \brief A callable PolymorphicFunctionObject that is /// equivalent to the \c child_c() function. template<long N> struct child_c { BOOST_PROTO_CALLABLE() template<typename Sig> struct result; template<typename This, typename Expr> struct result<This(Expr)> { typedef typename result_of::child_c<Expr, N>::type type; }; /// \brief Return the Nth child of the given expression. /// \param expr The expression node. /// \pre <tt>is_expr\<Expr\>::value</tt> is \c true /// \pre <tt>N \< Expr::proto_arity::value</tt> /// \return <tt>proto::child_c\<N\>(expr)</tt> /// \throw nothrow template<typename Expr> typename result_of::child_c<Expr &, N>::type operator ()(Expr &e) const { return result_of::child_c<Expr &, N>::call(e); } /// \overload /// template<typename Expr> typename result_of::child_c<Expr const &, N>::type operator ()(Expr const &e) const { return result_of::child_c<Expr const &, N>::call(e); } }; /// \brief A callable PolymorphicFunctionObject that is /// equivalent to the \c child() function. /// /// A callable PolymorphicFunctionObject that is /// equivalent to the \c child() function. \c N is required /// to be an MPL Integral Constant. template<typename N /* = mpl::long_<0>*/> struct child { BOOST_PROTO_CALLABLE() template<typename Sig> struct result; template<typename This, typename Expr> struct result<This(Expr)> { typedef typename result_of::child<Expr, N>::type type; }; /// \brief Return the Nth child of the given expression. /// \param expr The expression node. /// \pre <tt>is_expr\<Expr\>::value</tt> is \c true /// \pre <tt>N::value \< Expr::proto_arity::value</tt> /// \return <tt>proto::child\<N\>(expr)</tt> /// \throw nothrow template<typename Expr> typename result_of::child<Expr &, N>::type operator ()(Expr &e) const { return result_of::child<Expr &, N>::call(e); } /// \overload /// template<typename Expr> typename result_of::child<Expr const &, N>::type operator ()(Expr const &e) const { return result_of::child<Expr const &, N>::call(e); } }; /// \brief A callable PolymorphicFunctionObject that is /// equivalent to the \c value() function. struct value { BOOST_PROTO_CALLABLE() template<typename Sig> struct result; template<typename This, typename Expr> struct result<This(Expr)> { typedef typename result_of::value<Expr>::type type; }; /// \brief Return the value of the given terminal expression. /// \param expr The terminal expression node. /// \pre <tt>is_expr\<Expr\>::value</tt> is \c true /// \pre <tt>0 == Expr::proto_arity::value</tt> /// \return <tt>proto::value(expr)</tt> /// \throw nothrow template<typename Expr> typename result_of::value<Expr &>::type operator ()(Expr &e) const { return e.proto_base().child0; } /// \overload /// template<typename Expr> typename result_of::value<Expr const &>::type operator ()(Expr const &e) const { return e.proto_base().child0; } }; /// \brief A callable PolymorphicFunctionObject that is /// equivalent to the \c left() function. struct left { BOOST_PROTO_CALLABLE() template<typename Sig> struct result; template<typename This, typename Expr> struct result<This(Expr)> { typedef typename result_of::left<Expr>::type type; }; /// \brief Return the left child of the given binary expression. /// \param expr The expression node. /// \pre <tt>is_expr\<Expr\>::value</tt> is \c true /// \pre <tt>2 == Expr::proto_arity::value</tt> /// \return <tt>proto::left(expr)</tt> /// \throw nothrow template<typename Expr> typename result_of::left<Expr &>::type operator ()(Expr &e) const { return e.proto_base().child0; } /// \overload /// template<typename Expr> typename result_of::left<Expr const &>::type operator ()(Expr const &e) const { return e.proto_base().child0; } }; /// \brief A callable PolymorphicFunctionObject that is /// equivalent to the \c right() function. struct right { BOOST_PROTO_CALLABLE() template<typename Sig> struct result; template<typename This, typename Expr> struct result<This(Expr)> { typedef typename result_of::right<Expr>::type type; }; /// \brief Return the right child of the given binary expression. /// \param expr The expression node. /// \pre <tt>is_expr\<Expr\>::value</tt> is \c true /// \pre <tt>2 == Expr::proto_arity::value</tt> /// \return <tt>proto::right(expr)</tt> /// \throw nothrow template<typename Expr> typename result_of::right<Expr &>::type operator ()(Expr &e) const { return e.proto_base().child1; } template<typename Expr> typename result_of::right<Expr const &>::type operator ()(Expr const &e) const { return e.proto_base().child1; } }; } /// \brief A function that wraps non-Proto expression types in Proto /// terminals and leaves Proto expression types alone. /// /// The <tt>as_expr()</tt> function turns objects into Proto terminals if /// they are not Proto expression types already. Non-Proto types are /// held by value, if possible. Types which are already Proto types are /// left alone and returned by reference. /// /// This function can be called either with an explicitly specified /// \c Domain parameter (i.e., <tt>as_expr\<Domain\>(t)</tt>), or /// without (i.e., <tt>as_expr(t)</tt>). If no domain is /// specified, \c default_domain is assumed. /// /// If <tt>is_expr\<T\>::value</tt> is \c true, then the argument is /// returned unmodified, by reference. Otherwise, the argument is wrapped /// in a Proto terminal expression node according to the following rules. /// If \c T is a function type, let \c A be <tt>T &</tt>. Otherwise, let /// \c A be the type \c T stripped of cv-qualifiers. Then, \c as_expr() /// returns <tt>Domain()(terminal\<A\>::type::make(t))</tt>. /// /// \param t The object to wrap. template<typename T> typename add_const<typename result_of::as_expr<T, default_domain>::type>::type as_expr(T &t BOOST_PROTO_DISABLE_IF_IS_CONST(T) BOOST_PROTO_DISABLE_IF_IS_FUNCTION(T)) { return default_domain::as_expr<T>()(t); } /// \overload /// template<typename T> typename add_const<typename result_of::as_expr<T const, default_domain>::type>::type as_expr(T const &t) { return default_domain::as_expr<T const>()(t); } /// \overload /// template<typename Domain, typename T> typename add_const<typename result_of::as_expr<T, Domain>::type>::type as_expr(T &t BOOST_PROTO_DISABLE_IF_IS_CONST(T) BOOST_PROTO_DISABLE_IF_IS_FUNCTION(T)) { return typename Domain::template as_expr<T>()(t); } /// \overload /// template<typename Domain, typename T> typename add_const<typename result_of::as_expr<T const, Domain>::type>::type as_expr(T const &t) { return typename Domain::template as_expr<T const>()(t); } /// \brief A function that wraps non-Proto expression types in Proto /// terminals (by reference) and returns Proto expression types by /// reference /// /// The <tt>as_child()</tt> function turns objects into Proto terminals if /// they are not Proto expression types already. Non-Proto types are /// held by reference. Types which are already Proto types are simply /// returned as-is. /// /// This function can be called either with an explicitly specified /// \c Domain parameter (i.e., <tt>as_child\<Domain\>(t)</tt>), or /// without (i.e., <tt>as_child(t)</tt>). If no domain is /// specified, \c default_domain is assumed. /// /// If <tt>is_expr\<T\>::value</tt> is \c true, then the argument is /// returned as-is. Otherwise, \c as_child() returns /// <tt>Domain()(terminal\<T &\>::type::make(t))</tt>. /// /// \param t The object to wrap. template<typename T> typename add_const<typename result_of::as_child<T, default_domain>::type>::type as_child(T &t BOOST_PROTO_DISABLE_IF_IS_CONST(T) BOOST_PROTO_DISABLE_IF_IS_FUNCTION(T)) { return default_domain::as_child<T>()(t); } /// \overload /// template<typename T> typename add_const<typename result_of::as_child<T const, default_domain>::type>::type as_child(T const &t) { return default_domain::as_child<T const>()(t); } /// \overload /// template<typename Domain, typename T> typename add_const<typename result_of::as_child<T, Domain>::type>::type as_child(T &t BOOST_PROTO_DISABLE_IF_IS_CONST(T) BOOST_PROTO_DISABLE_IF_IS_FUNCTION(T)) { return typename Domain::template as_child<T>()(t); } /// \overload /// template<typename Domain, typename T> typename add_const<typename result_of::as_child<T const, Domain>::type>::type as_child(T const &t) { return typename Domain::template as_child<T const>()(t); } /// \brief Return the Nth child of the specified Proto expression. /// /// Return the Nth child of the specified Proto expression. If /// \c N is not specified, as in \c child(expr), then \c N is assumed /// to be <tt>mpl::long_\<0\></tt>. The child is returned by /// reference. /// /// \param expr The Proto expression. /// \pre <tt>is_expr\<Expr\>::value</tt> is \c true. /// \pre \c N is an MPL Integral Constant. /// \pre <tt>N::value \< Expr::proto_arity::value</tt> /// \throw nothrow /// \return A reference to the Nth child template<typename N, typename Expr> typename result_of::child<Expr &, N>::type child(Expr &e BOOST_PROTO_DISABLE_IF_IS_CONST(Expr)) { return result_of::child<Expr &, N>::call(e); } /// \overload /// template<typename N, typename Expr> typename result_of::child<Expr const &, N>::type child(Expr const &e) { return result_of::child<Expr const &, N>::call(e); } /// \overload /// template<typename Expr2> typename detail::expr_traits<typename Expr2::proto_base_expr::proto_child0>::reference child(Expr2 &expr2 BOOST_PROTO_DISABLE_IF_IS_CONST(Expr2)) { return expr2.proto_base().child0; } /// \overload /// template<typename Expr2> typename detail::expr_traits<typename Expr2::proto_base_expr::proto_child0>::const_reference child(Expr2 const &expr2) { return expr2.proto_base().child0; } /// \brief Return the Nth child of the specified Proto expression. /// /// Return the Nth child of the specified Proto expression. The child /// is returned by reference. /// /// \param expr The Proto expression. /// \pre <tt>is_expr\<Expr\>::value</tt> is \c true. /// \pre <tt>N \< Expr::proto_arity::value</tt> /// \throw nothrow /// \return A reference to the Nth child template<long N, typename Expr> typename result_of::child_c<Expr &, N>::type child_c(Expr &e BOOST_PROTO_DISABLE_IF_IS_CONST(Expr)) { return result_of::child_c<Expr &, N>::call(e); } /// \overload /// template<long N, typename Expr> typename result_of::child_c<Expr const &, N>::type child_c(Expr const &e) { return result_of::child_c<Expr const &, N>::call(e); } /// \brief Return the value stored within the specified Proto /// terminal expression. /// /// Return the the value stored within the specified Proto /// terminal expression. The value is returned by /// reference. /// /// \param expr The Proto terminal expression. /// \pre <tt>N::value == 0</tt> /// \throw nothrow /// \return A reference to the terminal's value template<typename Expr> typename result_of::value<Expr &>::type value(Expr &e BOOST_PROTO_DISABLE_IF_IS_CONST(Expr)) { return e.proto_base().child0; } /// \overload /// template<typename Expr> typename result_of::value<Expr const &>::type value(Expr const &e) { return e.proto_base().child0; } /// \brief Return the left child of the specified binary Proto /// expression. /// /// Return the left child of the specified binary Proto expression. The /// child is returned by reference. /// /// \param expr The Proto expression. /// \pre <tt>is_expr\<Expr\>::value</tt> is \c true. /// \pre <tt>2 == Expr::proto_arity::value</tt> /// \throw nothrow /// \return A reference to the left child template<typename Expr> typename result_of::left<Expr &>::type left(Expr &e BOOST_PROTO_DISABLE_IF_IS_CONST(Expr)) { return e.proto_base().child0; } /// \overload /// template<typename Expr> typename result_of::left<Expr const &>::type left(Expr const &e) { return e.proto_base().child0; } /// \brief Return the right child of the specified binary Proto /// expression. /// /// Return the right child of the specified binary Proto expression. The /// child is returned by reference. /// /// \param expr The Proto expression. /// \pre <tt>is_expr\<Expr\>::value</tt> is \c true. /// \pre <tt>2 == Expr::proto_arity::value</tt> /// \throw nothrow /// \return A reference to the right child template<typename Expr> typename result_of::right<Expr &>::type right(Expr &e BOOST_PROTO_DISABLE_IF_IS_CONST(Expr)) { return e.proto_base().child1; } /// \overload /// template<typename Expr> typename result_of::right<Expr const &>::type right(Expr const &e) { return e.proto_base().child1; } /// INTERNAL ONLY /// template<typename Domain> struct is_callable<functional::as_expr<Domain> > : mpl::true_ {}; /// INTERNAL ONLY /// template<typename Domain> struct is_callable<functional::as_child<Domain> > : mpl::true_ {}; /// INTERNAL ONLY /// template<long N> struct is_callable<functional::child_c<N> > : mpl::true_ {}; /// INTERNAL ONLY /// template<typename N> struct is_callable<functional::child<N> > : mpl::true_ {}; }} #if BOOST_WORKAROUND( BOOST_MSVC, >= 1400 ) #pragma warning(pop) #endif #endif