// Copyright (c) 2006  INRIA Sophia-Antipolis (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org)
//
// $URL: https://github.com/CGAL/cgal/blob/v5.4/Kernel_23/include/CGAL/Kernel/Return_base_tag.h $
// $Id: Return_base_tag.h 0779373 2020-03-26T13:31:46+01:00 Sébastien Loriot
// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s)     : Sylvain Pion

#ifndef CGAL_KERNEL_RETURN_BASE_TAG_H
#define CGAL_KERNEL_RETURN_BASE_TAG_H

#include <CGAL/config.h>

// This is a simple tag which is used as additional (first) argument in
// some kernel functors, to tell them to return the base (rep) class,
// instead of the main type (e.g. Kernel_base::Point_2 instead
// of Kernel::Point_2).  This is a minor optimization which prevents
// useless copies of the "reps".

// Those functors are only those used in the constructors of the kernel
// types like Point_2, so it's limited.

// The real solution will be to use "forwarding constructors", when they
// will be available in C++.
// In the mean time, this should be a mostly/hopefully internal hack.

namespace CGAL {

struct Return_base_tag {};

} //namespace CGAL

#endif
