[Oberon] Tidyness of iteration.

[peter at easthope.ca]

(* Pre-2013. *)
PROCEDURE LOOPiteration();
BEGIN
	Texts.OpenReader(R, t, 0);
	LOOP
		Texts.Read(R, ch);
		IF R.eot THEN EXIT ELSE (* Process ch *) END
	END	
END LOOPinteration.

Project Oberon 2013, Page 5.
"2. The LOOP and EXIT statements (repetitions with multiple exit points) have been discarded." 

(* Using REPEAT, R.eot must be checked twice in each iteration. *)
PROCEDURE REPEATiteration();
BEGIN
	Texts.OpenReader(R, t, 0);
	REPEAT
		IF ~R.eot THEN Texts.Read(R, ch); (* Process ch *) END
	UNTIL R.eot
END REPEATinteration.

(* Using WHILE, Texts.Read is duplicated. *)
PROCEDURE WHILEiteration();
BEGIN
	Texts.OpenReader(R, t, 0);
	Texts.Read(R, ch);
	WHILE ~R.eot
		(* Process ch *);
		Texts.Read(R, ch)
	END
END WHILEinteration.

Can the REPEAT example or the WHILE example be simplified further?
(One must wonder about discarding REPEAT and WHILE and retaining LOOP with 
strictly one EXIT.)

Thanks,            ... Lyall E.


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