Re: Can LPeg parse PNG?

[KHMan <keinhong@...>]

On 12/10/2016 7:18 PM, Soni L. wrote:
> On 10/12/16 12:12 AM, KHMan wrote:
> > On 12/10/2016 9:46 AM, Duncan Cross wrote:
> > > On Sat, Dec 10, 2016 at 12:10 AM, Soni L. wrote:
> > > > I was told PNG is a regular language, in the sense that you
> > > > can validate any
> > > > PNG chunk with a VERY VERY VERY LONG regex.
> > >
> > > Including the 32-bit CRC at the end of the chunk? That's got to
> > > be a
> > > hell of a regex.
> >
> > I'm really curious about the "I was told PNG is a regular
> > language" though. It directs the blame for the idea on an
> > anonymous someone else.
> >
> > Perhaps he has VERY VERY VERY LARGE amounts of free time this
> > weekend, or perhaps he wants to trap some unsuspecting folks
> > trying it. I think both.
>
> Each PNG chunk is a finite sequence of bytes. Thus, a long enough
> regex can parse a stream of PNG chunks.

Sure, sure.

Oh, don't mind me, I'm just shooting the breeze here. If I sounded 
too negative, it's because I'm a dinosaur in Internet years and I 
mostly sit back and gawk at the younger folks who enthusiastically 
apply themselves to interesting problems such as this one... :-) 
;-) It's a generation gap thing, no biggie.

--
Cheers,
Kein-Hong Man (esq.)
Selangor, Malaysia