[M3devel] Man or Boy test

[Martin Bishop]

Sorry if I wasn't clean, but what I am asking is for why specifically it 
segfaults, I'm sure it's something to do with the recursive nature of 
the problem, just not sure how Modula-3 handles it.

Martin Bishop wrote:
> I tried implementing Knuth's Man or Boy test in Modula-3, but I can't 
> get it to work.
>
> I assumed the code I had wouldn't work (and I was right), but 
> eventually I fiddled enough and got it to compile, but now it just 
> segfaults when run.
>
> MODULE ManOrBoy EXPORTS Main;
>
> IMPORT IO, Fmt;
>
> PROCEDURE Zero(): INTEGER = BEGIN RETURN 0; END Zero;
> PROCEDURE One(): INTEGER = BEGIN RETURN 1; END One;
> PROCEDURE Neg(): INTEGER = BEGIN RETURN -1; END Neg;
>
> PROCEDURE A(k:INTEGER; x1, x2, x3, x4, x5: INTEGER): INTEGER =
>
>  PROCEDURE B(): INTEGER =
>    BEGIN
>      DEC(k);
>      RETURN A(k, B(), x1, x2, x3, x4);
>    END B;
>
>  BEGIN
>    IF k <= 0 THEN
>      RETURN x4 + x5;
>    ELSE
>      RETURN B();
>    END;
>  END A;
>
> BEGIN
>  IO.Put(Fmt.Int(A(10, One(), Neg(), Neg(), One(), Zero())) & "\n");
> END ManOrBoy.
>
> All I know is that it segfaults at procedure B.
>