Chris@16: /*=============================================================================
Chris@16:     Copyright (c) 2001-2007 Joel de Guzman
Chris@16: 
Chris@16:     Distributed under the Boost Software License, Version 1.0. (See accompanying 
Chris@16:     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: ==============================================================================*/
Chris@16: #ifndef PHOENIX_STATEMENT_SWITCH_HPP
Chris@16: #define PHOENIX_STATEMENT_SWITCH_HPP
Chris@16: 
Chris@16: #include <boost/spirit/home/phoenix/core/composite.hpp>
Chris@16: #include <boost/spirit/home/phoenix/core/compose.hpp>
Chris@16: #include <boost/spirit/home/phoenix/core/nothing.hpp>
Chris@16: #include <boost/spirit/home/phoenix/statement/detail/switch_eval.hpp>
Chris@16: #include <boost/spirit/home/phoenix/statement/detail/switch.hpp>
Chris@16: #include <boost/utility/enable_if.hpp>
Chris@16: #include <boost/mpl/not.hpp>
Chris@16: 
Chris@16: namespace boost { namespace phoenix
Chris@16: {
Chris@16:     template <typename Derived, typename Actor>
Chris@16:     struct switch_case_base 
Chris@16:     {
Chris@16:         typedef Derived derived_t;
Chris@16:         typedef Actor actor_t;
Chris@16:         typedef typename Actor::no_nullary no_nullary;
Chris@16: 
Chris@16:         template <typename Env>
Chris@16:         struct result
Chris@16:         {
Chris@16:             typedef typename Actor::eval_type::template result<Env>::type type;
Chris@16:         };
Chris@16: 
Chris@16:         switch_case_base(Actor const& actor)
Chris@16:             : actor(actor) {}
Chris@16: 
Chris@16:         template <typename Env>
Chris@16:         typename result<Env>::type
Chris@16:         eval(Env const& env) const
Chris@16:         {
Chris@16:             return actor.eval(env);
Chris@16:         }
Chris@16: 
Chris@16:         Actor actor;
Chris@16:     };
Chris@16: 
Chris@16:     template <typename Actor, typename K, K Value>
Chris@16:     struct switch_case : switch_case_base<switch_case<Actor, K, Value>, Actor>
Chris@16:     {
Chris@16:         typedef switch_case_base<switch_case<Actor, K, Value>, Actor> base_t;
Chris@16:         static K const value = Value;
Chris@16:         static bool const is_default = false;
Chris@16: 
Chris@16:         switch_case(Actor const& actor)
Chris@16:             : base_t(actor) {}
Chris@16:     };
Chris@16: 
Chris@16:     template <typename Actor>
Chris@16:     struct default_case : switch_case_base<default_case<Actor>, Actor>
Chris@16:     {
Chris@16:         typedef switch_case_base<default_case<Actor>, Actor> base_t;
Chris@16:         static bool const is_default = true;
Chris@16: 
Chris@16:         default_case(Actor const& actor)
Chris@16:             : base_t(actor) {}
Chris@16:     };
Chris@16: 
Chris@16:     template <typename Cond>
Chris@16:     struct switch_gen
Chris@16:     {
Chris@16:         switch_gen(Cond const& cond)
Chris@16:             : cond(cond) {}
Chris@16: 
Chris@16:         template <typename Cases>
Chris@16:         typename lazy_enable_if<
Chris@16:             fusion::traits::is_sequence<Cases>
Chris@16:           , detail::switch_composite_actor<Cond, Cases>
Chris@16:         >::type
Chris@16:         operator[](Cases const& cases) const
Chris@16:         {
Chris@16:             typedef typename
Chris@16:                 detail::switch_composite<Cond, Cases>
Chris@16:             switch_composite;
Chris@16:             return switch_composite::eval(cond, cases);
Chris@16:         }
Chris@16: 
Chris@16:         template <typename D, typename A>
Chris@16:         actor<typename detail::
Chris@16:             switch_composite<Cond, fusion::vector<actor<D> > >::type>
Chris@16:         operator[](switch_case_base<D, A> const& case_) const
Chris@16:         {
Chris@16:             typedef typename
Chris@16:                 detail::switch_composite<Cond, fusion::vector<actor<D> > >
Chris@16:             switch_composite;
Chris@16:             return switch_composite::eval(cond,
Chris@16:                 fusion::vector<actor<D> >(static_cast<D const&>(case_)));
Chris@16:         }
Chris@16: 
Chris@16:         Cond cond;
Chris@16:     };
Chris@16: 
Chris@16:     template <typename Cond>
Chris@16:     inline switch_gen<typename as_actor<Cond>::type>
Chris@16:     switch_(Cond const& cond)
Chris@16:     {
Chris@16:         return switch_gen<typename as_actor<Cond>::type>(
Chris@16:             as_actor<Cond>::convert(cond));
Chris@16:     }
Chris@16: 
Chris@16:     template <int N, typename A0>
Chris@16:     switch_case<typename as_actor<A0>::type, int, N>
Chris@16:     case_(A0 const& _0)
Chris@16:     {
Chris@16:         return switch_case<typename as_actor<A0>::type, int, N>
Chris@16:             (as_actor<A0>::convert(_0));
Chris@16:     }
Chris@16: 
Chris@16:     template <typename A0>
Chris@16:     default_case<typename as_actor<A0>::type>
Chris@16:     default_(A0 const& _0)
Chris@16:     {
Chris@16:         return default_case<typename as_actor<A0>::type>
Chris@16:             (as_actor<A0>::convert(_0));
Chris@16:     }
Chris@16: 
Chris@16:     template <typename D0, typename A0, typename D1, typename A1>
Chris@16:     inline typename detail::compose_case_a<D0, D1>::type
Chris@16:     operator,(
Chris@16:         switch_case_base<D0, A0> const& _0
Chris@16:       , switch_case_base<D1, A1> const& _1
Chris@16:     )
Chris@16:     {
Chris@16:         return detail::compose_case_a<D0, D1>::eval(
Chris@16:             static_cast<D0 const&>(_0)
Chris@16:           , static_cast<D1 const&>(_1)
Chris@16:         );
Chris@16:     }
Chris@16: 
Chris@16:     template <typename Seq, typename D, typename A>
Chris@16:     inline typename
Chris@16:         lazy_enable_if<
Chris@16:             fusion::traits::is_sequence<Seq>
Chris@16:           , detail::compose_case_b<Seq, D>
Chris@16:         >::type
Chris@16:     operator,(Seq const& seq, switch_case_base<D, A> const& case_)
Chris@16:     {
Chris@16:         return detail::compose_case_b<Seq, D>::eval(
Chris@16:             seq, static_cast<D const&>(case_));
Chris@16:     }
Chris@16: 
Chris@16:     // Implementation of routines in detail/switch.hpp that depend on
Chris@16:     // the completeness of default_case.
Chris@16:     namespace detail {
Chris@16:         template <typename Cases>
Chris@16:         typename ensure_default<Cases>::type
Chris@16:         ensure_default<Cases>::eval(Cases const& cases, mpl::false_)
Chris@16:         {
Chris@16:             actor<default_case<actor<null_actor> > > default_
Chris@16:               = default_case<actor<null_actor> >(nothing);
Chris@16:             return fusion::push_front(cases, default_);
Chris@16:         }
Chris@16:     }
Chris@16: }}
Chris@16: 
Chris@16: #endif