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Re: PSC #055 2022-02-18

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February 21, 2022 04:57
Re: PSC #055 2022-02-18
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On Mon, 21 Feb 2022 at 04:01, demerphq <> wrote:

> On Mon, 21 Feb 2022, 07:24 Neil Bowers, <> wrote:
>> De-experimentalising variable-length look-behind (`experimental::vlb`).
>> See
> I don't think this is ready for prime time yet. The feature is way under
> tested, and without my recent PR it is plain broken, and I'm pretty sure I
> can find other issues and work that needs to be done given a bit of time. I
> have a feeling when I start poking it with a stick later today I'm going to
> find more issues that will need fixing and we are rapidly approaching code
> freezes and etc. I just don't think it's reasonable to expect to get it
> into a shape where I could in good conscience sign off on it in the time
> available.
> I'll do my best but I am not optimistic. The regex engine is garly as heck
> and even though I now have rewrapped my brain around the state machine I
> expect the changes needed will be in the compiler (regcomp.c) which is even
> more gnarly than the state machine (regexec.c).
To repeat what I said in the ticket....

I retract this. I was *wrong*. (Rarely have I been so pleased to say
that!)  I thought when I tested yesterday that (?<=x+) was allowed. But
further testing this morning shows it is not. The length restrictions
appear to be working correctly.  Also I thought my patch may have broken
(?<=) but they did not.

Therefore and assuming no further issues are revealed in additional tests,
especially nested lookbehind/lookahead tests, I am comfortable with signing
this off.

Karl did a great job with the length restrictions. I apologize for doubting

I will push a de-experimentalizing patch to go with my PR.

Sorry for the noise from my original mail. It was *very* hot here yesterday
and I came to incorrect conclusions while working on the fix for #19168.


perl -Mre=debug -e "/just|another|perl|hacker/"

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