DEFINITION Dictionaries

(*
 *	Entwicklung objekt-orientierter Bibliotheken, Aufgabe 15
 *
 *	Abstraktion fuer assoziative Arrays.
 *)
DEFINITION Dictionaries;

   IMPORT
      ConstStrings, Disciplines, Events, Iterators, Objects, Services;

   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:  Disciplines.Object;
	 END;

      CompareProc = PROCEDURE (entry1, entry2: Entry): INTEGER;

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

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

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

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

      CardProc = PROCEDURE (dict: Dictionary): INTEGER;

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

      GetCompareProc = PROCEDURE (dict: Dictionary; VAR compare: CompareProc);

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

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

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

   CONST
      keyExists = 0;			(* key exists *)
      keyNotFound = 1;			(* key not found *)
      errors = 2;

   TYPE
      ErrorCode = SHORTINT;		(* keyExists, keyNotFound *)
      ErrorEvent = POINTER TO ErrorEventRec;
      ErrorEventRec =
	 RECORD
	    (Events.EventRec)
	    errorcode: ErrorCode;
	    dictionary: Dictionary;
	    key: Key;
	 END;

   VAR
      error: Events.EventType;
      errormsg: ARRAY errors OF Events.Message;

   PROCEDURE CompareKeys(entry1, entry2: Entry): INTEGER;

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

   PROCEDURE Capabilities(dict: Dictionary): CapabilitySet;

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

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

   PROCEDURE Get(dict: Dictionary;
		  key: Key; VAR object: Disciplines.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 *)

   PROCEDURE GetCompare(dict: Dictionary; VAR compare: CompareProc);

END Dictionaries.