// Copyright (c) 1997  Utrecht University (The Netherlands),
// ETH Zurich (Switzerland), Freie Universitaet Berlin (Germany),
// INRIA Sophia-Antipolis (France), Martin-Luther-University Halle-Wittenberg
// (Germany), Max-Planck-Institute Saarbruecken (Germany), RISC Linz (Austria),
// and Tel-Aviv University (Israel).  All rights reserved.
//
// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; version 2.1 of the License.
// See the file LICENSE.LGPL distributed with CGAL.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $Source: /CVSROOT/CGAL/Packages/Modifier/include/CGAL/Modifier_base.h,v $
// $Revision: 1.4 $ $Date: 2003/10/21 12:20:49 $
// $Name:  $
//
// Author(s)     : Lutz Kettner  <kettner@inf.ethz.ch>

#ifndef CGAL_MODIFIER_BASE_H
#define CGAL_MODIFIER_BASE_H 1

CGAL_BEGIN_NAMESPACE

template <class R>
class Modifier_base {
    // Abstract Base Class for protected internal access.
    // It defines the common interface for all modifiers.
public:
    typedef R Representation;
    virtual void operator()( R& rep) = 0;
        // Postcondition: `rep' is a valid representation.
    virtual ~Modifier_base() {}
};

CGAL_END_NAMESPACE

#endif // CGAL_MODIFIER_BASE_H //
// EOF //