On Tue, Apr 12, 2011 at 08:34:49AM +1000, Erik de Castro Lopo wrote:
> Yury Euceda wrote:
>
> > Well, I have this option in my tool I developed. But I defined my own way
> > due my
> > own need (And well, I didn't know anything about this but I supposed to be
> > necesary
> > and I invented my own way not knowing the other notation)
> > for example:
> >
> > a>>3
> >
> > defines that a MUST appear three times ---> aaa is accepted
> >
> > and
> >
> > a<<3
> >
> > defines that a can appear 0, 1, 2 or 3 times ---> epsilon, a , aa , aaa are
> > accepted
> >
> > I would like to hear about your comments for my notation.
>
> I think that notation is far less clear than the regular expression
> notation that has been used in lexers for 30+ years. Ie
>
> a{0,3}
>
> Erik
I know you didn't reply to me. I'm the original author of this
thread, and since it is alive again, I did go with the {n,m}
notation exactly as presented by another user on this list.
I made this one of my atomic operators so I could push rule
counting down into what amounts to my inner loop. I was able to
simplify a couple of my existing grammars using this form as well.
-Alan
--
.i ma'a lo bradi ku penmi gi'e du
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