/*
 * Copyright (c) 1995, 1996 Gunther Schadow.  All rights reserved.
 *
 * 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 PG_REPEATBASE_H_
#define PG_REPEATBASE_H_

#include <pg_config.h>

#pragma interface

#include <PGObject.h>
#include <iostream.h>
#include <sys/types.h>

class RepeatBase : public PGObject
{
 protected:
  RepeatBase(PGObject::subclass_t);
  RepeatBase(const RepeatBase&);

  const RepeatBase& operator = (const RepeatBase&);

 public:
  ~RepeatBase();

  void unset();
  bool ispresent() const;

  PGObject& operator [] (u_int);
  
  PGObject  &car() const;
  RepeatBase *cdr() const;
  bool end() const;

  PGObject &prepend();
  PGObject &prepend(const PGObject&);
  PGObject &append();
  PGObject &append(const PGObject&);
  
  bool commit();
  bool OK() const;

 protected:
  PGObject  *_car;
  RepeatBase *_cdr;
  
  virtual PGObject*  ctora() const = 0;
  virtual PGObject*  ctora(const PGObject*) const = 0;
  virtual RepeatBase* ctord() const = 0;  
};

#ifndef OUTLINE
# include "RepeatBase.icc"
#endif

#endif /* !PG_REPEATBASE_H_ */