[Oberon] *****SPAM***** Re: *****SPAM***** Re: Oberon-2 type bound procedure scope

[Joerg]

In addition to August‘s example with TYPE, NW’s compiler accepts this:

PROCEDURE P;
  CONST max = 100;
  PROCEDURE Q;
    BEGIN Out.Int(max, 0); Out.Ln END Q;
  END P;

The parser nicely nests the scopes.
The parser finds the variables in the intermediate scopes but the generator has the access restrictions to them.

br
Jörg

> Am 12.12.2023 um 22:46 schrieb werner.heiz at gmail.com:
> 
> Sorry, if I missed something, but if this local/global rule is strictly
> applied without exception, recursive calls like this would not be allowed:
> 
> PROCEDURE P;  (*P is at scope level 0 = global scope *)
> 
>  PROCEDURE Q(n: INTEGER);  (* Q is at scope level 1 (local to P); n is at
> scope level 2 (local to Q) *)
>  BEGIN
>    IF n > 0 THEN DEC(n); Q(n) END;   (* not allowed if rule strictly
> applied as Q (scope level 1) is called from scope level 2 *)
>  END Q;
> 
> BEGIN (*P*)
>  Q(10);
> END P;
> 
> I'm currently working on an Oberon compiler just for fun, and I think this
> should be allowed.
> 
> Werner Heiz
> 
> -----Ursprüngliche Nachricht-----
> Von: Oberon <oberon-bounces at lists.inf.ethz.ch> Im Auftrag von August
> Karlstrom
> Gesendet: Mittwoch, 13. Dezember 2023 10:27
> An: oberon at lists.inf.ethz.ch
> Betreff: Re: [Oberon] *****SPAM***** Re: *****SPAM***** Re: Oberon-2 type
> bound procedure scope
> 
> On 2023-12-12 10:02, Diego Sardina wrote:
> [...]
>> ...however since then only strictly local and strictly global objects are
> available to a procedure.
> 
> Indeed, this has been confirmed by Niklaus Wirth. For instance I asked him
> about the validity of the following procedure:
> 
>    PROCEDURE P;
>       TYPE T = INTEGER;
> 
>       PROCEDURE Q(x: T): T;
>       RETURN 0
>       END Q;
>    END P;
> 
> His reply was "You are right. Your procedure Q should be diagnosed in
> error."
> 
> As mentioned before, the Project Oberon 2013 compiler does not fully conform
> to the language report. I don't know if it's due to lack of time to make the
> changes to the compiler or if he want's the implementation to be different.
> 
> 
> August
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