(* Lists.def provides an unordered list manipulation package.

Copyright (C) 2001-2023 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 Lists ;

(*
   Author     : Gaius Mulley
   Title      : Lists
   Date       : Tue Dec 12 20:53:36 EST 1989
   SYSTEM     : UNIX (GNU Modula-2)
   Description: Provides an unordered list manipulation package.
   Last update: $Date: 2010/10/03 19:01:05 $
   Version    : $Revision: 1.9 $
*)

FROM SYSTEM IMPORT WORD ;
FROM SymbolKey IMPORT PerformOperation ;

EXPORT QUALIFIED List,
                 InitList, KillList, PutItemIntoList, GetItemFromList,
                 GetIndexOfList,
                 NoOfItemsInList, IsItemInList, IncludeItemIntoList,
                 RemoveItemFromList, ForeachItemInListDo, DuplicateList ;

TYPE
   List ;


(*
   InitList - creates a new list, l.
*)

PROCEDURE InitList (VAR l: List) ;


(*
   KillList - deletes the complete list, l.
*)

PROCEDURE KillList (VAR l: List) ;


(*
   PutItemIntoList - places a CARDINAL, c, into list, l.
*)

PROCEDURE PutItemIntoList (l: List; c: WORD) ;


(*
   GetItemFromList - retrieves the nth WORD from list, l.
*)

PROCEDURE GetItemFromList (l: List; n: CARDINAL) : WORD ;


(*
   GetIndexOfList - returns the index for WORD, c, in list, l.
                    If more than one CARDINAL, c, exists the index
                    for the first is returned.
*)

PROCEDURE GetIndexOfList (l: List; c: WORD) : CARDINAL ;


(*
   NoOfItemsInList - returns the number of items in list, l.
*)

PROCEDURE NoOfItemsInList (l: List) : CARDINAL ;


(*
   IncludeItemIntoList - adds a WORD, c, into a list providing
                         the value does not already exist.
*)

PROCEDURE IncludeItemIntoList (l: List; c: WORD) ;


(*
   RemoveItemFromList - removes a WORD, c, from a list.
                        It assumes that this value only appears once.
*)

PROCEDURE RemoveItemFromList (l: List; c: WORD) ;


(*
   IsItemInList - returns true if a WORD, c, was found in list, l.
*)

PROCEDURE IsItemInList (l: List; c: WORD) : BOOLEAN ;


(*
   ForeachItemInListDo - calls procedure, P, foreach item in list, l.
*)

PROCEDURE ForeachItemInListDo (l: List; P: PerformOperation) ;


(*
   DuplicateList - returns a duplicate list derived from, l.
*)

PROCEDURE DuplicateList (l: List) : List ;


END Lists.