verb-token.hpp

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/*
  VERB-TOKEN.hpp  -  double dispatch based on DSL tokens

  Copyright (C)         Lumiera.org
    2014,               Hermann Vosseler <Ichthyostega@web.de>

  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation; either version 2 of
  the License, or (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/


#ifndef LIB_VERB_TOKEN_H
#define LIB_VERB_TOKEN_H


#include "lib/symbol.hpp"
#include "lib/util.hpp"

#include <utility>
#include <string>


namespace lib {
  
  using std::string;
  
  
  template<class REC, class SIG>
  class VerbToken;
  
  template<class REC, class RET, typename... ARGS>
  class VerbToken<REC, RET(ARGS...)>
    {
    public:
      typedef RET (REC::*Handler) (ARGS...);
      
    protected:
      Handler handler_;
      Literal token_;
      
    public:
      RET
      applyTo (REC& receiver, ARGS&& ...args)
        {
          REQUIRE ("NIL" != token_);
          return (receiver.*handler_)(std::forward<ARGS>(args)...);
        }
      
      VerbToken(Handler handlerFunction, Literal token)
        : handler_(handlerFunction)
        , token_(token)
        { }
      
      VerbToken()
        : handler_{}
        , token_("NIL")
        { }
      
      /* default copyable */
      
      operator string()  const
        {
          return string(token_);
        }
      
      Literal const&
      getID()  const
        {
          return token_;
        }
      
      bool operator== (VerbToken const& o)  const { return token_ == o.token_; }
      bool operator!= (VerbToken const& o)  const { return token_ != o.token_; }
    };
  
#define VERB(RECEIVER, FUN) VERB_##FUN (&RECEIVER::FUN, STRINGIFY(FUN))
  
  
  
  
  
} // namespace lib  
#endif /*LIB_VERB_TOKEN_H*/