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(* SymbolKey.def binary tree operations for storing symbols.
Copyright (C) 2001-2025 Free Software Foundation, Inc.
Contributed by Gaius Mulley <gaius.mulley@southwales.ac.uk>.
This file is part of GNU Modula-2.
GNU Modula-2 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 3, or (at your option)
any later version.
GNU Modula-2 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 GNU Modula-2; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. *)
DEFINITION MODULE SymbolKey ;
(*
Author : Gaius Mulley
Title : SymbolKey
Date : 4/3/87
Description: Provides binary tree operations for storing symbols.
Used by the MODULE SymbolTable to provide scoping of symbols.
Last update: Date: Wed 31-01-1990 Time: 18:20:32.63
Mon Aug 30 12:07:12 BST 1999
*)
FROM SYSTEM IMPORT WORD ;
FROM NameKey IMPORT Name ;
EXPORT QUALIFIED NulKey, SymbolTree,
IsSymbol, PerformOperation,
InitTree, KillTree, GetSymKey, PutSymKey, DelSymKey,
IsEmptyTree,
DoesTreeContainAny, ForeachNodeDo, ContainsSymKey,
NoOfNodes, ForeachNodeConditionDo ;
CONST
NulKey = 0 ;
TYPE
SymbolTree ;
IsSymbol = PROCEDURE (WORD) : BOOLEAN ;
PerformOperation = PROCEDURE (WORD) ;
(*
InitTree - Initializes a SymbolTree pointed to by t.
*)
PROCEDURE InitTree (VAR t: SymbolTree) ;
(*
KillTree - Destroys the SymbolTree pointed to by t.
*)
PROCEDURE KillTree (VAR t: SymbolTree) ;
(*
GetSymKey - Searches the SymbolTree t for an entry NameKey. If
found then the SymKey is returned. NulKey = not found.
*)
PROCEDURE GetSymKey (t: SymbolTree; NameKey: Name) : WORD ;
(*
PutSymKey - Puts an symbol entry NameKey in the SymbolTree t.
SymKey is the value stored with NameKey.
*)
PROCEDURE PutSymKey (t: SymbolTree; NameKey: Name; SymKey: WORD) ;
(*
DelSymKey - Deletes a symbol entry NameKey in the SymbolTree t.
*)
PROCEDURE DelSymKey (t: SymbolTree; NameKey: Name) ;
(*
IsEmptyTree - returns true if SymbolTree, t, is empty.
*)
PROCEDURE IsEmptyTree (t: SymbolTree) : BOOLEAN ;
(*
DoesTreeContainAny - returns true if SymbolTree, t, contains any
symbols which in turn return true when procedure,
P, is called with a symbol as its parameter.
*)
PROCEDURE DoesTreeContainAny (t: SymbolTree; P: IsSymbol) : BOOLEAN ;
(*
ForeachNodeDo - for each node in SymbolTree, t, a procedure, P,
is called with the node symbol as its parameter.
It traverse the tree in order.
*)
PROCEDURE ForeachNodeDo (t: SymbolTree; P: PerformOperation) ;
(*
ContainsSymKey - return TRUE if tree, t, contains an entry for, NameKey.
*)
PROCEDURE ContainsSymKey (t: SymbolTree; NameKey: Name) : BOOLEAN ;
(*
NoOfNodes - returns the number of nodes in the tree t.
*)
PROCEDURE NoOfNodes (t: SymbolTree; condition: IsSymbol) : CARDINAL ;
(*
ForeachNodeConditionDo - traverse the tree t and for any node which satisfied
condition call P.
*)
PROCEDURE ForeachNodeConditionDo (t: SymbolTree;
condition: IsSymbol;
P: PerformOperation) ;
END SymbolKey.
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