DEFINITION Dictionaries

(*
 *	Entwicklung objekt-orientierter Bibliotheken, Aufgabe 10
 *
 *	Abstraktion fuer assoziative Arrays.
 *)
DEFINITION Dictionaries;

   IMPORT ConstStrings, Disciplines, Iterators, Objects;

   CONST
      any = 0;
      sorted = 1;
      reverse = 2;

   TYPE
      Order = Iterators.Mode;		(* any, sorted, reverse *)

      Key = ConstStrings.String;

      Entry = POINTER TO EntryRec;
      EntryRec =
	 RECORD
	    (Disciplines.ObjectRec)
	    key:     Key;
	    object:  Objects.Object;
	 END;

      Dictionary = POINTER TO DictionaryRec;
      DictionaryRec =
	 RECORD
	    (Disciplines.ObjectRec)
	 END;

      AddProc = PROCEDURE (dict: Dictionary; key: Key; object: Objects.Object);

      RemoveProc = PROCEDURE (dict: Dictionary; key: Key);

      GetProc = PROCEDURE (dict: Dictionary; key: Key;
			   VAR object: Objects.Object): BOOLEAN;

      CardProc = PROCEDURE (dict: Dictionary): INTEGER;

      GetEntriesProc = PROCEDURE (dict: Dictionary; order: Order;
				 VAR it: Iterators.Iterator);

      Interface = POINTER TO InterfaceRec;
      InterfaceRec =
	 RECORD
	    (Objects.ObjectRec)
	    add:        AddProc;		(* mandatory *)
	    remove:     RemoveProc;		(* optional *)
	    get:        GetProc;		(* mandatory *)
	    card:       CardProc;		(* mandatory *)
	    getEntries: GetEntriesProc;		(* optional *)
	 END;

   CONST
      remove = 0;
      getEntries = 1;
      sortEntries = 2;			(* specifying order makes sense *)

   TYPE
      CapabilitySet = SET; (* OF remove..sortEntries *)

   PROCEDURE Init(dict: Dictionary; if: Interface; caps: CapabilitySet);

   PROCEDURE Add(dict: Dictionary; key: Key; object: Objects.Object);

   PROCEDURE Remove(dict: Dictionary; key: Key);

   PROCEDURE Get(dict: Dictionary;
		  key: Key; VAR object: Objects.Object): BOOLEAN;

   PROCEDURE Card(dict: Dictionary): INTEGER;

   PROCEDURE GetEntries(dict: Dictionary; order: Order;
			VAR it: Iterators.Iterator);
      (* iteration must not be carried on over change operations *)

END Dictionaries.