boost/proto/matches.hpp
/////////////////////////////////////////////////////////////////////////////// /// \file matches.hpp /// Contains definition of matches\<\> metafunction for determining if /// a given expression matches a given pattern. // // 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_MATCHES_HPP_EAN_11_03_2006 #define BOOST_PROTO_MATCHES_HPP_EAN_11_03_2006 #include <boost/config.hpp> #include <boost/detail/workaround.hpp> #include <boost/preprocessor/cat.hpp> #include <boost/preprocessor/arithmetic/dec.hpp> #include <boost/preprocessor/arithmetic/sub.hpp> #include <boost/preprocessor/iteration/iterate.hpp> #include <boost/preprocessor/facilities/intercept.hpp> #include <boost/preprocessor/punctuation/comma_if.hpp> #include <boost/preprocessor/repetition/enum.hpp> #include <boost/preprocessor/repetition/enum_params.hpp> #include <boost/preprocessor/repetition/enum_shifted.hpp> #include <boost/preprocessor/repetition/enum_binary_params.hpp> #include <boost/preprocessor/repetition/enum_shifted_params.hpp> #include <boost/preprocessor/repetition/enum_trailing_params.hpp> #include <boost/preprocessor/repetition/enum_params_with_a_default.hpp> #include <boost/preprocessor/repetition/repeat.hpp> #include <boost/config.hpp> #include <boost/mpl/logical.hpp> #include <boost/mpl/eval_if.hpp> #include <boost/proto/detail/template_arity.hpp> #include <boost/utility/enable_if.hpp> #if BOOST_WORKAROUND(BOOST_MSVC, == 1310) #include <boost/type_traits/is_array.hpp> #endif #include <boost/type_traits/is_const.hpp> #include <boost/type_traits/is_convertible.hpp> #include <boost/type_traits/is_reference.hpp> #include <boost/type_traits/is_pointer.hpp> #include <boost/proto/proto_fwd.hpp> #include <boost/proto/traits.hpp> #include <boost/proto/transform/when.hpp> #include <boost/proto/transform/impl.hpp> #if defined(_MSC_VER) && (_MSC_VER >= 1020) # pragma warning(push) # pragma warning(disable:4305) // 'specialization' : truncation from 'const int' to 'bool' #endif #define BOOST_PROTO_LOGICAL_typename_G BOOST_PP_ENUM_PARAMS(BOOST_PROTO_MAX_LOGICAL_ARITY, typename G) #define BOOST_PROTO_LOGICAL_G BOOST_PP_ENUM_PARAMS(BOOST_PROTO_MAX_LOGICAL_ARITY, G) namespace boost { namespace proto { namespace detail { template<typename Expr, typename BasicExpr, typename Grammar> struct matches_; template<bool B, typename Pred> struct and_2; template<typename And, typename Expr, typename State, typename Data> struct _and_impl; template<typename T, typename U> struct array_matches : mpl::false_ {}; template<typename T, std::size_t M> struct array_matches<T[M], T *> : mpl::true_ {}; template<typename T, std::size_t M> struct array_matches<T[M], T const *> : mpl::true_ {}; template<typename T, std::size_t M> struct array_matches<T[M], T[proto::N]> : mpl::true_ {}; template<typename T, typename U BOOST_PROTO_TEMPLATE_ARITY_PARAM(long Arity = detail::template_arity<U>::value) > struct lambda_matches : mpl::false_ {}; template<typename T> struct lambda_matches<T, proto::_ BOOST_PROTO_TEMPLATE_ARITY_PARAM(-1)> : mpl::true_ {}; template<typename T> struct lambda_matches<T, T BOOST_PROTO_TEMPLATE_ARITY_PARAM(-1)> : mpl::true_ {}; template<typename T, std::size_t M, typename U> struct lambda_matches<T[M], U BOOST_PROTO_TEMPLATE_ARITY_PARAM(-1)> : array_matches<T[M], U> {}; template<typename T, std::size_t M> struct lambda_matches<T[M], _ BOOST_PROTO_TEMPLATE_ARITY_PARAM(-1)> : mpl::true_ {}; template<typename T, std::size_t M> struct lambda_matches<T[M], T[M] BOOST_PROTO_TEMPLATE_ARITY_PARAM(-1)> : mpl::true_ {}; template<template<typename> class T, typename Expr0, typename Grammar0> struct lambda_matches<T<Expr0>, T<Grammar0> BOOST_PROTO_TEMPLATE_ARITY_PARAM(1) > : lambda_matches<Expr0, Grammar0> {}; // vararg_matches_impl template<typename Args1, typename Back, long From, long To> struct vararg_matches_impl; // vararg_matches template<typename Expr, typename Args1, typename Args2, typename Back, bool Can, bool Zero, typename Void = void> struct vararg_matches : mpl::false_ {}; template<typename Expr, typename Args1, typename Args2, typename Back> struct vararg_matches<Expr, Args1, Args2, Back, true, true, typename Back::proto_is_vararg_> : matches_< Expr , proto::basic_expr<ignore, Args1, Args1::arity> , proto::basic_expr<ignore, Args2, Args1::arity> > {}; template<typename Expr, typename Args1, typename Args2, typename Back> struct vararg_matches<Expr, Args1, Args2, Back, true, false, typename Back::proto_is_vararg_> : and_2< matches_< Expr , proto::basic_expr<ignore, Args1, Args2::arity> , proto::basic_expr<ignore, Args2, Args2::arity> >::value , vararg_matches_impl<Args1, typename Back::proto_grammar, Args2::arity + 1, Args1::arity> > {}; // How terminal_matches<> handles references and cv-qualifiers. // The cv and ref matter *only* if the grammar has a top-level ref. // // Expr | Grammar | Matches? // ------------------------------------- // T T yes // T & T yes // T const & T yes // T T & no // T & T & yes // T const & T & no // T T const & no // T & T const & no // T const & T const & yes template<typename T, typename U> struct is_cv_ref_compatible : mpl::true_ {}; template<typename T, typename U> struct is_cv_ref_compatible<T, U &> : mpl::false_ {}; template<typename T, typename U> struct is_cv_ref_compatible<T &, U &> : mpl::bool_<is_const<T>::value == is_const<U>::value> {}; #if BOOST_WORKAROUND(BOOST_MSVC, == 1310) // MSVC-7.1 has lots of problems with array types that have been // deduced. Partially specializing terminal_matches<> on array types // doesn't seem to work. template< typename T , typename U , bool B = is_array<BOOST_PROTO_UNCVREF(T)>::value > struct terminal_array_matches : mpl::false_ {}; template<typename T, typename U, std::size_t M> struct terminal_array_matches<T, U(&)[M], true> : is_convertible<T, U(&)[M]> {}; template<typename T, typename U> struct terminal_array_matches<T, U(&)[proto::N], true> : is_convertible<T, U *> {}; template<typename T, typename U> struct terminal_array_matches<T, U *, true> : is_convertible<T, U *> {}; // terminal_matches template<typename T, typename U> struct terminal_matches : mpl::or_< mpl::and_< is_cv_ref_compatible<T, U> , lambda_matches< BOOST_PROTO_UNCVREF(T) , BOOST_PROTO_UNCVREF(U) > > , terminal_array_matches<T, U> > {}; #else // terminal_matches template<typename T, typename U> struct terminal_matches : mpl::and_< is_cv_ref_compatible<T, U> , lambda_matches< BOOST_PROTO_UNCVREF(T) , BOOST_PROTO_UNCVREF(U) > > {}; template<typename T, std::size_t M> struct terminal_matches<T(&)[M], T(&)[proto::N]> : mpl::true_ {}; template<typename T, std::size_t M> struct terminal_matches<T(&)[M], T *> : mpl::true_ {}; // Avoid ambiguity errors on MSVC #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1500)) template<typename T, std::size_t M> struct terminal_matches<T const (&)[M], T const[M]> : mpl::true_ {}; #endif #endif template<typename T> struct terminal_matches<T, T> : mpl::true_ {}; template<typename T> struct terminal_matches<T &, T> : mpl::true_ {}; template<typename T> struct terminal_matches<T const &, T> : mpl::true_ {}; template<typename T> struct terminal_matches<T, proto::_> : mpl::true_ {}; template<typename T> struct terminal_matches<T, exact<T> > : mpl::true_ {}; template<typename T, typename U> struct terminal_matches<T, proto::convertible_to<U> > : is_convertible<T, U> {}; // matches_ template<typename Expr, typename BasicExpr, typename Grammar> struct matches_ : mpl::false_ {}; template<typename Expr, typename BasicExpr> struct matches_< Expr, BasicExpr, proto::_ > : mpl::true_ {}; template<typename Expr, typename Tag, typename Args1, long N1, typename Args2, long N2> struct matches_< Expr, proto::basic_expr<Tag, Args1, N1>, proto::basic_expr<Tag, Args2, N2> > : vararg_matches< Expr, Args1, Args2, typename Args2::back_, (N1+2 > N2), (N2 > N1) > {}; template<typename Expr, typename Tag, typename Args1, long N1, typename Args2, long N2> struct matches_< Expr, proto::basic_expr<Tag, Args1, N1>, proto::basic_expr<proto::_, Args2, N2> > : vararg_matches< Expr, Args1, Args2, typename Args2::back_, (N1+2 > N2), (N2 > N1) > {}; template<typename Expr, typename Tag, typename Args1, typename Args2> struct matches_< Expr, proto::basic_expr<Tag, Args1, 0>, proto::basic_expr<Tag, Args2, 0> > : terminal_matches<typename Args1::child0, typename Args2::child0> {}; template<typename Expr, typename Tag, typename Args1, typename Args2, long N2> struct matches_< Expr, proto::basic_expr<Tag, Args1, 0>, proto::basic_expr<proto::_, Args2, N2> > : mpl::false_ {}; template<typename Expr, typename Tag, typename Args1, typename Args2> struct matches_< Expr, proto::basic_expr<Tag, Args1, 0>, proto::basic_expr<proto::_, Args2, 0> > : terminal_matches<typename Args1::child0, typename Args2::child0> {}; template<typename Expr, typename Tag, typename Args1, typename Args2> struct matches_< Expr, proto::basic_expr<Tag, Args1, 1>, proto::basic_expr<Tag, Args2, 1> > : matches_< typename detail::expr_traits<typename Args1::child0>::value_type::proto_derived_expr , typename detail::expr_traits<typename Args1::child0>::value_type::proto_grammar , typename Args2::child0::proto_grammar > {}; template<typename Expr, typename Tag, typename Args1, typename Args2> struct matches_< Expr, proto::basic_expr<Tag, Args1, 1>, proto::basic_expr<proto::_, Args2, 1> > : matches_< typename detail::expr_traits<typename Args1::child0>::value_type::proto_derived_expr , typename detail::expr_traits<typename Args1::child0>::value_type::proto_grammar , typename Args2::child0::proto_grammar > {}; #include <boost/proto/detail/and_n.hpp> #include <boost/proto/detail/or_n.hpp> #include <boost/proto/detail/matches_.hpp> #include <boost/proto/detail/vararg_matches_impl.hpp> #include <boost/proto/detail/lambda_matches.hpp> // handle proto::if_ template<typename Expr, typename Tag, typename Args, long Arity, typename If, typename Then, typename Else> struct matches_<Expr, proto::basic_expr<Tag, Args, Arity>, proto::if_<If, Then, Else> > : mpl::eval_if_c< remove_reference< typename when<_, If>::template impl<Expr, int, int>::result_type >::type::value , matches_<Expr, proto::basic_expr<Tag, Args, Arity>, typename Then::proto_grammar> , matches_<Expr, proto::basic_expr<Tag, Args, Arity>, typename Else::proto_grammar> >::type { typedef typename mpl::if_c< remove_reference< typename when<_, If>::template impl<Expr, int, int>::result_type >::type::value , Then , Else >::type which; }; // handle degenerate cases of proto::or_ template<typename Expr, typename BasicExpr> struct matches_<Expr, BasicExpr, or_<> > : mpl::false_ { typedef not_<_> which; }; template<typename Expr, typename BasicExpr, typename G0> struct matches_<Expr, BasicExpr, or_<G0> > : matches_<Expr, BasicExpr, typename G0::proto_grammar> { typedef G0 which; }; // handle degenerate cases of proto::and_ template<typename Expr, typename BasicExpr> struct matches_<Expr, BasicExpr, and_<> > : mpl::true_ {}; template<typename Expr, typename BasicExpr, typename G0> struct matches_<Expr, BasicExpr, and_<G0> > : matches_<Expr, BasicExpr, typename G0::proto_grammar> {}; // handle proto::not_ template<typename Expr, typename BasicExpr, typename Grammar> struct matches_<Expr, BasicExpr, not_<Grammar> > : mpl::not_<matches_<Expr, BasicExpr, typename Grammar::proto_grammar> > {}; // handle proto::switch_ template<typename Expr, typename Tag, typename Args, long Arity, typename Cases, typename Transform> struct matches_<Expr, proto::basic_expr<Tag, Args, Arity>, switch_<Cases, Transform> > : matches_< Expr , proto::basic_expr<Tag, Args, Arity> , typename Cases::template case_< typename when<_,Transform>::template impl<Expr,int,int>::result_type >::proto_grammar > { typedef typename Cases::template case_< typename when<_, Transform>::template impl<Expr, int, int>::result_type > which; }; // handle proto::switch_ with the default Transform for specially for better compile times template<typename Expr, typename Tag, typename Args, long Arity, typename Cases> struct matches_<Expr, proto::basic_expr<Tag, Args, Arity>, switch_<Cases> > : matches_< Expr , proto::basic_expr<Tag, Args, Arity> , typename Cases::template case_<Tag>::proto_grammar > { typedef typename Cases::template case_<Tag> which; }; } /// \brief A Boolean metafunction that evaluates whether a given /// expression type matches a grammar. /// /// <tt>matches\<Expr,Grammar\></tt> inherits (indirectly) from /// \c mpl::true_ if <tt>Expr::proto_grammar</tt> matches /// <tt>Grammar::proto_grammar</tt>, and from \c mpl::false_ /// otherwise. /// /// Non-terminal expressions are matched against a grammar /// according to the following rules: /// /// \li The wildcard pattern, \c _, matches any expression. /// \li An expression <tt>expr\<AT, listN\<A0,A1,...An\> \></tt> /// matches a grammar <tt>expr\<BT, listN\<B0,B1,...Bn\> \></tt> /// if \c BT is \c _ or \c AT, and if \c Ax matches \c Bx for /// each \c x in <tt>[0,n)</tt>. /// \li An expression <tt>expr\<AT, listN\<A0,...An,U0,...Um\> \></tt> /// matches a grammar <tt>expr\<BT, listM\<B0,...Bn,vararg\<V\> \> \></tt> /// if \c BT is \c _ or \c AT, and if \c Ax matches \c Bx /// for each \c x in <tt>[0,n)</tt> and if \c Ux matches \c V /// for each \c x in <tt>[0,m)</tt>. /// \li An expression \c E matches <tt>or_\<B0,B1,...Bn\></tt> if \c E /// matches some \c Bx for \c x in <tt>[0,n)</tt>. /// \li An expression \c E matches <tt>and_\<B0,B1,...Bn\></tt> if \c E /// matches all \c Bx for \c x in <tt>[0,n)</tt>. /// \li An expression \c E matches <tt>if_\<T,U,V\></tt> if /// <tt>boost::result_of\<when\<_,T\>(E,int,int)\>::type::value</tt> /// is \c true and \c E matches \c U; or, if /// <tt>boost::result_of\<when\<_,T\>(E,int,int)\>::type::value</tt> /// is \c false and \c E matches \c V. (Note: \c U defaults to \c _ /// and \c V defaults to \c not_\<_\>.) /// \li An expression \c E matches <tt>not_\<T\></tt> if \c E does /// not match \c T. /// \li An expression \c E matches <tt>switch_\<C,T\></tt> if /// \c E matches <tt>C::case_\<boost::result_of\<T(E)\>::type\></tt>. /// (Note: T defaults to <tt>tag_of\<_\>()</tt>.) /// /// A terminal expression <tt>expr\<AT,term\<A\> \></tt> matches /// a grammar <tt>expr\<BT,term\<B\> \></tt> if \c BT is \c AT or /// \c proto::_ and if one of the following is true: /// /// \li \c B is the wildcard pattern, \c _ /// \li \c A is \c B /// \li \c A is <tt>B &</tt> /// \li \c A is <tt>B const &</tt> /// \li \c B is <tt>exact\<A\></tt> /// \li \c B is <tt>convertible_to\<X\></tt> and /// <tt>is_convertible\<A,X\>::value</tt> is \c true. /// \li \c A is <tt>X[M]</tt> or <tt>X(&)[M]</tt> and /// \c B is <tt>X[proto::N]</tt>. /// \li \c A is <tt>X(&)[M]</tt> and \c B is <tt>X(&)[proto::N]</tt>. /// \li \c A is <tt>X[M]</tt> or <tt>X(&)[M]</tt> and /// \c B is <tt>X*</tt>. /// \li \c B lambda-matches \c A (see below). /// /// A type \c B lambda-matches \c A if one of the following is true: /// /// \li \c B is \c A /// \li \c B is the wildcard pattern, \c _ /// \li \c B is <tt>T\<B0,B1,...Bn\></tt> and \c A is /// <tt>T\<A0,A1,...An\></tt> and for each \c x in /// <tt>[0,n)</tt>, \c Ax and \c Bx are types /// such that \c Ax lambda-matches \c Bx template<typename Expr, typename Grammar> struct matches : detail::matches_< typename Expr::proto_derived_expr , typename Expr::proto_grammar , typename Grammar::proto_grammar > {}; /// INTERNAL ONLY /// template<typename Expr, typename Grammar> struct matches<Expr &, Grammar> : detail::matches_< typename Expr::proto_derived_expr , typename Expr::proto_grammar , typename Grammar::proto_grammar > {}; /// \brief A wildcard grammar element that matches any expression, /// and a transform that returns the current expression unchanged. /// /// The wildcard type, \c _, is a grammar element such that /// <tt>matches\<E,_\>::value</tt> is \c true for any expression /// type \c E. /// /// The wildcard can also be used as a stand-in for a template /// argument when matching terminals. For instance, the following /// is a grammar that will match any <tt>std::complex\<\></tt> /// terminal: /// /// \code /// BOOST_MPL_ASSERT(( /// matches< /// terminal<std::complex<double> >::type /// , terminal<std::complex< _ > > /// > /// )); /// \endcode /// /// When used as a transform, \c _ returns the current expression /// unchanged. For instance, in the following, \c _ is used with /// the \c fold\<\> transform to fold the children of a node: /// /// \code /// struct CountChildren /// : or_< /// // Terminals have no children /// when<terminal<_>, mpl::int_<0>()> /// // Use fold<> to count the children of non-terminals /// , otherwise< /// fold< /// _ // <-- fold the current expression /// , mpl::int_<0>() /// , mpl::plus<_state, mpl::int_<1> >() /// > /// > /// > /// {}; /// \endcode struct _ : transform<_> { typedef _ proto_grammar; template<typename Expr, typename State, typename Data> struct impl : transform_impl<Expr, State, Data> { typedef Expr result_type; /// \param expr An expression /// \return \c e #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; } }; }; namespace detail { template<typename Expr, typename State, typename Data> struct _and_impl<proto::and_<>, Expr, State, Data> : proto::_::impl<Expr, State, Data> {}; template<typename G0, typename Expr, typename State, typename Data> struct _and_impl<proto::and_<G0>, Expr, State, Data> : proto::when<proto::_, G0>::template impl<Expr, State, Data> {}; } /// \brief Inverts the set of expressions matched by a grammar. When /// used as a transform, \c not_\<\> returns the current expression /// unchanged. /// /// If an expression type \c E does not match a grammar \c G, then /// \c E \e does match <tt>not_\<G\></tt>. For example, /// <tt>not_\<terminal\<_\> \></tt> will match any non-terminal. template<typename Grammar> struct not_ : transform<not_<Grammar> > { typedef not_ proto_grammar; template<typename Expr, typename State, typename Data> struct impl : transform_impl<Expr, State, Data> { typedef Expr result_type; /// \param e An expression /// \pre <tt>matches\<Expr,not_\>::value</tt> is \c true. /// \return \c e #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; } }; }; /// \brief Used to select one grammar or another based on the result /// of a compile-time Boolean. When used as a transform, \c if_\<\> /// selects between two transforms based on a compile-time Boolean. /// /// When <tt>if_\<If,Then,Else\></tt> is used as a grammar, \c If /// must be a Proto transform and \c Then and \c Else must be grammars. /// An expression type \c E matches <tt>if_\<If,Then,Else\></tt> if /// <tt>boost::result_of\<when\<_,If\>(E,int,int)\>::type::value</tt> /// is \c true and \c E matches \c U; or, if /// <tt>boost::result_of\<when\<_,If\>(E,int,int)\>::type::value</tt> /// is \c false and \c E matches \c V. /// /// The template parameter \c Then defaults to \c _ /// and \c Else defaults to \c not\<_\>, so an expression type \c E /// will match <tt>if_\<If\></tt> if and only if /// <tt>boost::result_of\<when\<_,If\>(E,int,int)\>::type::value</tt> /// is \c true. /// /// \code /// // A grammar that only matches integral terminals, /// // using is_integral<> from Boost.Type_traits. /// struct IsIntegral /// : and_< /// terminal<_> /// , if_< is_integral<_value>() > /// > /// {}; /// \endcode /// /// When <tt>if_\<If,Then,Else\></tt> is used as a transform, \c If, /// \c Then and \c Else must be Proto transforms. When applying /// the transform to an expression \c E, state \c S and data \c V, /// if <tt>boost::result_of\<when\<_,If\>(E,S,V)\>::type::value</tt> /// is \c true then the \c Then transform is applied; otherwise /// the \c Else transform is applied. /// /// \code /// // Match a terminal. If the terminal is integral, return /// // mpl::true_; otherwise, return mpl::false_. /// struct IsIntegral2 /// : when< /// terminal<_> /// , if_< /// is_integral<_value>() /// , mpl::true_() /// , mpl::false_() /// > /// > /// {}; /// \endcode template< typename If , typename Then // = _ , typename Else // = not_<_> > struct if_ : transform<if_<If, Then, Else> > { typedef if_ proto_grammar; template<typename Expr, typename State, typename Data> struct impl : transform_impl<Expr, State, Data> { typedef typename when<_, If>::template impl<Expr, State, Data>::result_type condition; typedef typename mpl::if_c< remove_reference<condition>::type::value , when<_, Then> , when<_, Else> >::type which; typedef typename which::template impl<Expr, State, Data>::result_type result_type; /// \param e An expression /// \param s The current state /// \param d A data of arbitrary type /// \return <tt>which::impl<Expr, State, Data>()(e, s, d)</tt> result_type operator ()( typename impl::expr_param e , typename impl::state_param s , typename impl::data_param d ) const { return typename which::template impl<Expr, State, Data>()(e, s, d); } }; }; /// \brief For matching one of a set of alternate grammars. Alternates /// tried in order to avoid ambiguity. When used as a transform, \c or_\<\> /// applies the transform associated with the first grammar that matches /// the expression. /// /// An expression type \c E matches <tt>or_\<B0,B1,...Bn\></tt> if \c E /// matches any \c Bx for \c x in <tt>[0,n)</tt>. /// /// When applying <tt>or_\<B0,B1,...Bn\></tt> as a transform with an /// expression \c e of type \c E, state \c s and data \c d, it is /// equivalent to <tt>Bx()(e, s, d)</tt>, where \c x is the lowest /// number such that <tt>matches\<E,Bx\>::value</tt> is \c true. template<BOOST_PROTO_LOGICAL_typename_G> struct or_ : transform<or_<BOOST_PROTO_LOGICAL_G> > { typedef or_ proto_grammar; /// \param e An expression /// \param s The current state /// \param d A data of arbitrary type /// \pre <tt>matches\<Expr,or_\>::value</tt> is \c true. /// \return <tt>which()(e, s, d)</tt>, where <tt>which</tt> is the /// sub-grammar that matched <tt>Expr</tt>. template<typename Expr, typename State, typename Data> struct impl : detail::matches_< typename Expr::proto_derived_expr , typename Expr::proto_grammar , or_ >::which::template impl<Expr, State, Data> {}; template<typename Expr, typename State, typename Data> struct impl<Expr &, State, Data> : detail::matches_< typename Expr::proto_derived_expr , typename Expr::proto_grammar , or_ >::which::template impl<Expr &, State, Data> {}; }; /// \brief For matching all of a set of grammars. When used as a /// transform, \c and_\<\> applies the transforms associated with /// the each grammar in the set, and returns the result of the last. /// /// An expression type \c E matches <tt>and_\<B0,B1,...Bn\></tt> if \c E /// matches all \c Bx for \c x in <tt>[0,n)</tt>. /// /// When applying <tt>and_\<B0,B1,...Bn\></tt> as a transform with an /// expression \c e, state \c s and data \c d, it is /// equivalent to <tt>(B0()(e, s, d),B1()(e, s, d),...Bn()(e, s, d))</tt>. template<BOOST_PROTO_LOGICAL_typename_G> struct and_ : transform<and_<BOOST_PROTO_LOGICAL_G> > { typedef and_ proto_grammar; template<typename Expr, typename State, typename Data> struct impl : detail::_and_impl<and_, Expr, State, Data> {}; }; /// \brief For matching one of a set of alternate grammars, which /// are looked up based on some property of an expression. The /// property on which to dispatch is specified by the \c Transform /// template parameter, which defaults to <tt>tag_of\<_\>()</tt>. /// That is, when the \c Trannsform is not specified, the alternate /// grammar is looked up using the tag type of the current expression. /// /// When used as a transform, \c switch_\<\> applies the transform /// associated with the grammar that matches the expression. /// /// \note \c switch_\<\> is functionally identical to \c or_\<\> but /// is often more efficient. It does a fast, O(1) lookup using the /// result of the specified transform to find a sub-grammar that may /// potentially match the expression. /// /// An expression type \c E matches <tt>switch_\<C,T\></tt> if \c E /// matches <tt>C::case_\<boost::result_of\<T(E)\>::type\></tt>. /// /// When applying <tt>switch_\<C,T\></tt> as a transform with an /// expression \c e of type \c E, state \c s of type \S and data /// \c d of type \c D, it is equivalent to /// <tt>C::case_\<boost::result_of\<T(E,S,D)\>::type\>()(e, s, d)</tt>. template<typename Cases, typename Transform> struct switch_ : transform<switch_<Cases, Transform> > { typedef switch_ proto_grammar; template<typename Expr, typename State, typename Data> struct impl : Cases::template case_< typename when<_, Transform>::template impl<Expr, State, Data>::result_type >::template impl<Expr, State, Data> {}; }; /// INTERNAL ONLY (This is merely a compile-time optimization for the common case) /// template<typename Cases> struct switch_<Cases> : transform<switch_<Cases> > { typedef switch_ proto_grammar; template<typename Expr, typename State, typename Data> struct impl : Cases::template case_<typename Expr::proto_tag>::template impl<Expr, State, Data> {}; template<typename Expr, typename State, typename Data> struct impl<Expr &, State, Data> : Cases::template case_<typename Expr::proto_tag>::template impl<Expr &, State, Data> {}; }; /// \brief For forcing exact matches of terminal types. /// /// By default, matching terminals ignores references and /// cv-qualifiers. For instance, a terminal expression of /// type <tt>terminal\<int const &\>::type</tt> will match /// the grammar <tt>terminal\<int\></tt>. If that is not /// desired, you can force an exact match with /// <tt>terminal\<exact\<int\> \></tt>. This will only /// match integer terminals where the terminal is held by /// value. template<typename T> struct exact {}; /// \brief For matching terminals that are convertible to /// a type. /// /// Use \c convertible_to\<\> to match a terminal that is /// convertible to some type. For example, the grammar /// <tt>terminal\<convertible_to\<int\> \></tt> will match /// any terminal whose argument is convertible to an integer. /// /// \note The trait \c is_convertible\<\> from Boost.Type_traits /// is used to determinal convertibility. template<typename T> struct convertible_to {}; /// \brief For matching a Grammar to a variable number of /// sub-expressions. /// /// An expression type <tt>expr\<AT, listN\<A0,...An,U0,...Um\> \></tt> /// matches a grammar <tt>expr\<BT, listM\<B0,...Bn,vararg\<V\> \> \></tt> /// if \c BT is \c _ or \c AT, and if \c Ax matches \c Bx /// for each \c x in <tt>[0,n)</tt> and if \c Ux matches \c V /// for each \c x in <tt>[0,m)</tt>. /// /// For example: /// /// \code /// // Match any function call expression, irregardless /// // of the number of function arguments: /// struct Function /// : function< vararg<_> > /// {}; /// \endcode /// /// When used as a transform, <tt>vararg\<G\></tt> applies /// <tt>G</tt>'s transform. template<typename Grammar> struct vararg : Grammar { /// INTERNAL ONLY typedef void proto_is_vararg_; }; /// INTERNAL ONLY /// template<BOOST_PROTO_LOGICAL_typename_G> struct is_callable<or_<BOOST_PROTO_LOGICAL_G> > : mpl::true_ {}; /// INTERNAL ONLY /// template<BOOST_PROTO_LOGICAL_typename_G> struct is_callable<and_<BOOST_PROTO_LOGICAL_G> > : mpl::true_ {}; /// INTERNAL ONLY /// template<typename Grammar> struct is_callable<not_<Grammar> > : mpl::true_ {}; /// INTERNAL ONLY /// template<typename If, typename Then, typename Else> struct is_callable<if_<If, Then, Else> > : mpl::true_ {}; /// INTERNAL ONLY /// template<typename Grammar> struct is_callable<vararg<Grammar> > : mpl::true_ {}; /// INTERNAL ONLY /// template<typename Cases, typename Transform> struct is_callable<switch_<Cases, Transform> > : mpl::true_ {}; }} #undef BOOST_PROTO_LOGICAL_typename_G #undef BOOST_PROTO_LOGICAL_G #if defined(_MSC_VER) && (_MSC_VER >= 1020) # pragma warning(pop) #endif #endif