[perl #130586] [REGEX] "Iteration Past End" with Empty Character Class that has unescaped space in it <[email protected]>

Further discussion on https://github.com/rakudo/rakudo/issues/1622.

On 2017-01-21 14:13:42, [email protected] wrote:
> On Wed, 18 Jan 2017 18:16:20 -0800, [email protected] wrote:
> > the :sigspace adverb does not affect spaces inside character class.
> > Should it?
> >
> No, I don't think so. `<.ws>` can match any number of characters
> (including zero). A char class is defining something a matcher for a
> single character.
>
> > Note that having JUST space inside also causes a weird error to be
> > thrown:
> >
> > <Zoffix> m: say " " ~~ m:s/<-[ ]>/
> > <camelia> rakudo-moar 1aeea1: OUTPUT«===SORRY!===␤Iteration past end
> > of iterator␤»
> >
> That one's certainly a bug. Since whitespace in a charclass is not
> significant, then it should complain about an empty charclass,
> preferably with a hint about space.
>
> > <Zoffix> m: say " " ~~ m:s/<-[x ]>/
> > <camelia> rakudo-moar 1aeea1: OUTPUT«｢ ｣␤»
> This matches because it's the same as m:s/<-[x]>/. You'd need to write
> <-[x\ ]> to make the space significant.
>
> > <Zoffix> m: say " " ~~ m:s/<-[ x]>/
> > <camelia> rakudo-moar 1aeea1: OUTPUT«｢ ｣␤»
> Ditto.
>
> /jnthn