Chris@16: /*==============================================================================
Chris@16:     Copyright (c) 2001-2010 Joel de Guzman
Chris@16:     Copyright (c) 2010 Thomas Heller
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 BOOST_PHOENIX_CORE_REFERENCE_HPP
Chris@16: #define BOOST_PHOENIX_CORE_REFERENCE_HPP
Chris@16: 
Chris@16: #include <boost/phoenix/core/limits.hpp>
Chris@16: #include <boost/ref.hpp>
Chris@16: #include <boost/phoenix/core/actor.hpp>
Chris@16: #include <boost/phoenix/core/terminal.hpp>
Chris@16: #include <boost/utility/result_of.hpp>
Chris@16: 
Chris@16: namespace boost { namespace phoenix
Chris@16: {
Chris@16:     /////////////////////////////////////////////////////////////////////////////
Chris@16:     //
Chris@16:     // reference
Chris@16:     //
Chris@16:     //      function for evaluating references, e.g. ref(123)
Chris@16:     //
Chris@16:     /////////////////////////////////////////////////////////////////////////////
Chris@16:     namespace expression
Chris@16:     {
Chris@16:         template <typename T>
Chris@16:         struct reference
Chris@16:             : expression::terminal<reference_wrapper<T> >
Chris@16:         {
Chris@16:             typedef
Chris@16:                 typename expression::terminal<reference_wrapper<T> >::type
Chris@16:                 type;
Chris@16: 
Chris@16:             static const type make(T & t)
Chris@16:             {
Chris@16:                 typename reference<T>::type const e = {{boost::ref(t)}};
Chris@16:                 return e;
Chris@16:             }
Chris@16:         };
Chris@16:         
Chris@16:         template <typename T>
Chris@16:         struct reference<T const>
Chris@16:             : expression::terminal<reference_wrapper<T const> >
Chris@16:         {
Chris@16:             typedef
Chris@16:                 typename expression::terminal<reference_wrapper<T const> >::type
Chris@16:                 type;
Chris@16: 
Chris@16:             static const type make(T const & t)
Chris@16:             {
Chris@16:                 typename reference<T const>::type const e = {{boost::cref(t)}};
Chris@16:                 return e;
Chris@16:             }
Chris@16:         };
Chris@16:     }
Chris@16: 
Chris@16:     namespace rule
Chris@16:     {
Chris@16:         struct reference
Chris@16:             : expression::reference<proto::_>
Chris@16:         {};
Chris@16:     }
Chris@16: 
Chris@16:     template <typename T>
Chris@101:     inline
Chris@16:     typename expression::reference<T>::type const
Chris@101:     ref(T & t)
Chris@16:     {
Chris@16:         return expression::reference<T>::make(t);
Chris@16:     }
Chris@16: 
Chris@16:     template <typename T>
Chris@101:     inline
Chris@16:     typename expression::reference<T const>::type const
Chris@101:     cref(T const & t)
Chris@16:     {
Chris@16:         return expression::reference<T const>::make(t);
Chris@16:     }
Chris@16: 
Chris@16:     // Call out boost::reference_wrapper for special handling
Chris@16:     template<typename T>
Chris@16:     struct is_custom_terminal<boost::reference_wrapper<T> >
Chris@16:       : mpl::true_
Chris@16:     {};
Chris@16: 
Chris@16:     // Special handling for boost::reference_wrapper
Chris@16:     template<typename T>
Chris@16:     struct custom_terminal<boost::reference_wrapper<T> >
Chris@16:     {
Chris@16:         typedef T &result_type;
Chris@16: 
Chris@16:         template <typename Context>
Chris@16:         T &operator()(boost::reference_wrapper<T> r, Context &) const
Chris@16:         {
Chris@16:             return r;
Chris@16:         }
Chris@16:     };
Chris@16:     
Chris@16:     template<typename Expr>
Chris@16:     struct custom_terminal<boost::reference_wrapper<actor<Expr> > >
Chris@16:     {
Chris@16:         template <typename Sig>
Chris@16:         struct result;
Chris@16: 
Chris@16:         template <typename This, typename Context>
Chris@16:         struct result<This(boost::reference_wrapper<actor<Expr> > const &, Context)>
Chris@16:             : boost::result_of<evaluator(actor<Expr> &, Context)>
Chris@16:         {};
Chris@16: 
Chris@16:         template <typename This, typename Context>
Chris@16:         struct result<This(boost::reference_wrapper<actor<Expr> > &, Context)>
Chris@16:             : boost::result_of<evaluator(actor<Expr> &, Context)>
Chris@16:         {};
Chris@16: 
Chris@16:         template <typename Context>
Chris@16:         typename boost::result_of<evaluator(actor<Expr> &, Context const &)>::type
Chris@16:         operator()(boost::reference_wrapper<actor<Expr> > & r, Context const & ctx) const
Chris@16:         {
Chris@16:             return boost::phoenix::eval(r, ctx);
Chris@16:         }
Chris@16:     };
Chris@16:     
Chris@16:     template<typename Expr>
Chris@16:     struct custom_terminal<boost::reference_wrapper<actor<Expr> const> >
Chris@16:     {
Chris@16:         template <typename Sig>
Chris@16:         struct result;
Chris@16: 
Chris@16:         template <typename This, typename Context>
Chris@16:         struct result<This(boost::reference_wrapper<actor<Expr> const> const &, Context)>
Chris@16:             : boost::result_of<evaluator(actor<Expr> const&, Context)>
Chris@16:         {};
Chris@16: 
Chris@16:         template <typename This, typename Context>
Chris@16:         struct result<This(boost::reference_wrapper<actor<Expr> const> &, Context)>
Chris@16:             : boost::result_of<evaluator(actor<Expr> const&, Context)>
Chris@16:         {};
Chris@16: 
Chris@16:         template <typename Context>
Chris@16:         typename boost::result_of<evaluator(actor<Expr> const&, Context const &)>::type
Chris@16:         operator()(boost::reference_wrapper<actor<Expr> const> const & r, Context & ctx) const
Chris@16:         {
Chris@16:             return boost::phoenix::eval(unwrap_ref(r), ctx);
Chris@16:         }
Chris@16:     };
Chris@16: }}
Chris@16: 
Chris@16: #endif