/* -*-C-*-

Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
    1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
    2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016,
    2017, 2018, 2019, 2020 Massachusetts Institute of Technology

This file is part of MIT/GNU Scheme.

MIT/GNU Scheme 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.

MIT/GNU Scheme 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 MIT/GNU Scheme; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301,
USA.

*/

#ifndef AVLTREE_H
#define AVLTREE_H

/* This file contains external declarations for a simple
   AVL tree library.
   It is used by the MIT/GNU Scheme microcode to quickly map
   names to indices into various tables.  */

#include "config.h"

extern const char * tree_error_message;
extern const char * tree_error_noise;

typedef struct tree_node_s * tree_node;

struct tree_node_s
{
  int height;
  tree_node left;
  tree_node rite;
  const char * name;
  unsigned long value;
};

extern tree_node tree_build (unsigned long, const char **, unsigned long);
extern tree_node tree_lookup (tree_node, const char *);
extern tree_node tree_insert (tree_node, const char *, unsigned long);
extern void tree_free (tree_node);

#endif /* AVLTREE_H */
