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Postings from February 2013
On 17 February 2013 02:56, Tom Christiansen <tchrist@perl.com> wrote:
> I've seen people try to do this:
>
> my $delim = $if_something ? " " : qr/\s+/;
> @fields = split $delim, $string;
>
> And they are *very* surprised that it doesn't work the same as
>
> @fields = split $if_something ? " " : /\s+/, $string;
>
> That is really hard to explain, you know? Not easy to justify either.
>
> Either it should clearly state that this space trick is a magic literal
> literal and that cannot be in variable, or else it should be fixed so
> anything that shows up as a U+0020 counts as that.
Well it looks like this isnt going to be easy at all. And frankly I
don't understand why some of the changes were done. It looks like FC
in an attempt to fix a "bug" (of dubious provenance) ended up making
this kind of thing a lot harder, and in fact you could argue that the
change that FC made in 5255171e6cd0accee6f76ea2980e32b3b5b8e171
completely makes this impossible.
I personally think that commit was a mistake, and that #94490 should
have been marked as "not a bug". I regret I didnt spot it at the time.
Had 5255171e6 not been committed fixing this would have been possible.
/grrrrr
Yves
git log -SSKIPWHITE
commit cccd1425414e6518c1fc8b7bcaccfb119320c513
Author: Father Chrysostomos <sprout@cpan.org>
Date: Thu Oct 11 09:27:18 2012 -0700
Define RXf_SPLIT and RXf_SKIPWHITE as 0
They are on longer used in core, and we need room for more flags.
The only CPAN modules that use them check whether RXf_SPLIT is set
(which no longer happens) before setting RXf_SKIPWHITE (which is
ignored).
commit 5255171e6cd0accee6f76ea2980e32b3b5b8e171
Author: Father Chrysostomos <sprout@cpan.org>
Date: Sat Sep 22 17:54:12 2012 -0700
[perl #94490] const fold should not trigger special split " "
The easiest way to fix this was to move the special handling out of
the regexp engine. Now a flag is set on the split op itself for
this case. A real regexp is still created, as that is the most
convenient way to propagate locale settings, and it prevents the
need to rework pp_split to handle a null regexp.
This also means that custom regexp plugins no longer need to handle
split specially (which they all do currently).
commit 7bd1e61447493a93405e0d15fe2f8a0b6bf71de1
Author: Yves Orton <demerphq@gmail.com>
Date: Thu Jun 28 22:14:14 2007 +0000
Replace pattern parsing logic with optree "parsing" logic.
p4raw-id: //depot/perl@31496
commit 0ac6acaed7c2092a5668c6b70ddeaf3003e989d8
Author: Ævar Arnfjörð Bjarmason <avar@cpan.org>
Date: Thu Jun 28 20:06:50 2007 +0000
Move the RXf_WHITE logic for split " " into the regex engine
From: "Ævar Arnfjörð Bjarmason"
<avarab@gmail.com>
Message-ID: <51dd1af80706281306i4dbba39em3eeb8da1d67ea27c@mail.gmail.com>
(with tweaks)
p4raw-id: //depot/perl@31495
--
perl -Mre=debug -e "/just|another|perl|hacker/"
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