(*
6.3 Height Balanced Binary Search Tree Utilities

This module provides the facility for displaying the hierarchy of
a binary tree on the terminal while presenting an example using
active iterators. Printing the tree is also possible depending
on whether standard output has been so redirected. Also provided
is a routine to determine the height of a given tree.
*)

DEFINITION MODULE AVLSUMIU;
(*==============================================================
    Version  : V2.01  08 December 1989.
    Compiler : JPI TopSpeed Modula-2
    Component: AVL Tree SUMI Utilities

    REVISION HISTORY
    v1.00  17 Mar 1988  C. Lins
      Initial implementation for TML Modula-2.
    v1.01  01 Oct 1988  C. Lins
      Cleanup of comments.
          Changed PrintTree to use a single procedure parameter.
          Added HeightOf selector.
    v1.03  29 Jan 1989  C. Lins
      Changed to use Key and Data aliases for generic Items.
    v2.00  08 Oct 1989  C. Lins
         Created generic pc version
    v2.01  08 Dec 1989  I.S.C. Houston.
          Adapted to JPI Compiler:
          Use of type transfer functions instead of VAL.
          Use of shortened library module names.

        (C) Copyright 1989 Charles A. Lins
==============================================================*)

FROM TreeTypes IMPORT
    (*--Type*) Key, Data;

FROM AVLSUMI IMPORT
    (*--Type*) Tree, Balance;


        (*-----------------------*)

(*
6.3.1 Utility Selectors

HeightOf returns the height of the given tree.
*)

PROCEDURE HeightOf (    theTree : Tree     (*--in   *))
                                                                : CARDINAL (*--out  *);

(*
6.3.2 Debugging Iterators

PrintTree iterates over the given tree such that the nodes may be
printed. Trees are normally displayed with the root at the top and
the leaves at the bottom. To simplify the printing process, PrintTree
displays the tree rotated 90Æ to the left. Thus the root is shown at
the left of the page/screen with the leaves at the right. Furthermore,
the left branches are shown towards the bottom of the display and the
right branches at the top. The PrintProc routine is responsible for
indenting the display appropriately based on the level parameter.
*)

TYPE  Level    = CARDINAL;

TYPE  PrintProc  = PROCEDURE (Level, Key, Data, Balance);

PROCEDURE PrintTree (    theTree: Tree       (*--in   *);
                         print  : PrintProc  (*--in   *));

END AVLSUMIU.