_THE OBERON PROGRAMMING LANGUAGE_
by Josef Templ
  

Example 1:

MODULE M;
IMPORT M1, M2 := MyModule;

TYPE
  T* = RECORD
    f1*: INTEGER;
    f2: ARRAY 32 OF CHAR
  END ;

PROCEDURE P*(VAR p: T);
BEGIN
  M1.P(p.f1, p.f2)
END P;

END M.


Example 2: 

  WITH v: T1 DO
    v treated as beeing declared with static
    type T1 in this statement sequence
  END



Example 3: 

TYPE
  Object = POINTER TO ObjDesc;
  ObjDesc = RECORD ... END ;

  ObjMsg = RECORD END ;

  CopyMsg = RECORD(ObjMsg)
    deep: BOOLEAN; cpy: Object
  END ;

  ConsumeMsg = RECORD(ObjMsg)
    obj: Object; x, y: INTEGER
  END ;


Example 4: 
 
PROCEDURE Handle (O: Object; VAR M: ObjMsg);
BEGIN
  IF M IS CopyMsg THEN handle copy message
  ELSIF M IS ... handle further message types
  ELSE ignore
  END
END Handle;


Example 5: 


(a)

TYPE   Object = POINTER TO ObjDesc;
  ObjMsg = RECORD END ;
  Handler = PROCEDURE (O: Object; VAR M: ObjMsg);
  ObjDesc = RECORD
    handle: Handler
  END ;


(b)


TYPE
  MyObject = POINTER TO MyObjDesc;
  MyObjDesc = RECORD (Object)
    extended fields
  END ;



(c)

VAR o: MyObject;
NEW(o); o.handle := MyHandle;


(d)

VAR m: CopyMsg;
m.deep := TRUE; m.obj := NIL;
o.handle(o, m);


Example 6:

PROCEDURE MyHandle (O: Object; VAR M: ObjMsg);
BEGIN
  WITH O: MyObject DO
    IF M IS CopyMsg THEN handle copy message
    ELSIF M IS ... handle further message types
    ELSE Objects.Handle(O, M)
    END
  END
END MyHandle;


Example 7:

PROCEDURE Broadcast(VAR M: ObjMsg);
  VAR o: Object;
BEGIN o := firstObj;
  WHILE o _ NIL DO o.handle(o, M); o := nextObj END
END Broadcast;