Re: %prec doesn't seem to work?

[Adam Smalin]

Interesting, but than the issue is how do I make > > higher than > and ?:
but lower than *
I think i'm going to go through severe pain. I'm going to keep this last so
i can make all syntax changes at the end and break everything once.



On Wed, Apr 3, 2013 at 12:39 AM, Akim Demaille <address@hidden> wrote:

>
> Le 3 avr. 2013 à 04:52, Adam Smalin <address@hidden> a écrit :
>
> > It didnt seem to do anything. First i wrote
> >
> >    | rval '<' rval
> >    | rval '<' '<' rval %dprec 1
> >    | rval '>' rval %dprec 1
> >    | rval '>' '>' rval
> >
> > than after not getting the results i tried adding %dprec 2 to the other
> two
> > lines. Then i changed one to 3s wondering if that would solve it. All in
> > all it didnt seem to do anything :| is it because i already have
> precedence
> > rules on '<' and '>'?
> >
> > I than tried moving the above out of my main expression and doing
> something
> > similar with your sum/prod example. The problem is if i hide rval in the
> > prod (pretend i'm doing addition/multiplication) I
> >
> > 1) have to go straight to literals which means higher precedence wont
> work
> > because i'm not using rval
> > 2) use rval which would break everything because you cant have a rval
> rval
> > in the language and actually that rule would mean rval+ where + means one
> > or more
> > 3) rewrite all my rules to be like the prod/sum example. The expr rule
> (am
> > i calling it right?) is 150lines so that is going to be brutal to
> rewrite.
> >
> > The way i been checking if this works is by looking at 1>2< <3>4 and
> seeing
> > if the left (and right) are both literals (vs an expression for
> failure). I
> > checked with << and saw it pass. Than  did < < and saw it fail with
> %prec,
> > %dprec 1/3 (with the other having no dprec and a 2)
> >
> > crap. I have no idea how i can fix this without rewriting it all.
> > If %left and %right seem to do things why doesnt %prec seem to do what i
> > need. There must be a way? I'm just going to pretend i will have to
> rewrite
> > this because now after going through the above i think i need to rewrite
> > those 150+ lines which is going to be difficult.
>
> You should post a small, self contained, example, if you'd like people
> to give a try to your problem.  No need for the whole set of operators,
> just a few.
>
> For %dprec to be useful, you need to leave conflicts for the given
> tokens, if you "fix" everything with %left and others, it cannot come into
> action.
>
>