Re: Look for a LALR grammar for visual basic

> Scott Stanchfield <thetick@scruz.net> wrote:
> >Unfornately, my NDA with them prevents me from saying much more about
> >it... I think I can say that it was a fairly nasty beast in some areas:
> >Think about
> >
> > IF x = 1 THEN
> > END
> > 100: END IF
> >
> >which would complicate a grammar significantly (yes, VB allows a label
> >on things like "END IF" -- yuck!


Gene Wirchenko wrote:
> If you're going to allow goto, it makes sense to me to allow a
> branch to the end of a block (from within the block only I hope).


I'd agree if the label were on the next statement _after_ the if block,
as in


    IF x = 1 THEN
        END
    END IF
    100


or were on a separate line (a true null statement) before the END IF.


I'm pretty sure your C example would need to be


    if (x == 1) {
        exit(EXIT_SUCCESS);
target ; }


(note the semi for the null statement.)


Labels are normally only allowed in front of a statement. END IF isn't
a statement, but a block terminator. Allowing labels at the beginning
of any line makes the language incredibly nasty to implement with no
added benefit to a user...


-- Scott
--

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