expr.h

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/****
 Hierarchical Data Objects
 Copyright (C) 2005-2010 Werner Van Belle
 http://flow.yellowcouch.org/data/

 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
****/
#ifndef __loaded__expr_h__
#define __loaded__expr_h__
using namespace std;
#line 1 "expr.h++"
#include "reference-count.h"
namespace BorgIv{
  class ExpData;
  
  class Key
  {
  public:
    virtual ~Key()
    {
    };
  };

  class Exp: public Smart<ExpData>, public Key
  {
  public:
    Exp();
    Exp(ExpData * d);
    Exp(ExpData& scratch);
    Exp operator[](Key* key) const;
    template <class TargetType> 
    operator const TargetType() const
    {
      return dynamic_cast<const TargetType>(ptr);
    }

    void operator =(ExpData* data)
    {
      Smart<ExpData>::operator=((const Smart<ExpData>)data);
    }
  };
  
  class ExpData: public ReferenceCount
  {
  protected:
    friend class Exp;
    virtual ExpData* new_copy() const = 0;
    virtual Exp operator[](Key* key) const = 0;
    ExpData* copy_if_necessary() 
    {
      if (reference_count==0) return new_copy();
      return this;
    }
  };

  Exp::Exp(ExpData * d): Smart<ExpData>(d->copy_if_necessary())
  {
    assert(d);
  }

  Exp::Exp(ExpData& scratch): Smart<ExpData>(scratch.copy_if_necessary())
  {
  }

  Exp Exp::operator[](Key* key) const
  {
    return ptr[0][key];
  }
  
  Exp::Exp(): Smart<ExpData>()
  {
  };
  
} // end namespace
#endif // __loaded__expr_h__

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