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Re: PATCH: [perl #58182] partial, "The Unicode Bug". Add unicode semantics for \s, \w

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May 18, 2010 12:22
Re: PATCH: [perl #58182] partial, "The Unicode Bug". Add unicode semantics for \s, \w
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On 18 May 2010 20:29, Jesse Vincent <> wrote:
> On Tue, May 18, 2010 at 06:20:15PM +0000, ?var Arnfj?r? Bjarmason wrote:
>> On Tue, May 18, 2010 at 17:52, karl williamson <> wrote:
>> > I asked Yves privately about this, and he wonders if it is worth trying to
>> > not break constructs like '/foo/lt +2'
>> I don't think it's worth it. We should just pick the modifier letters
>> that make sense and not bend over backwards to be backwards compatible
>> with a *very* small amount of code out there.
> I'd rather we design a solution that doesn't break backward
> compatibility, no matter how much code we _think_ it might break. If
> that turns out to be completely untenable, then we can talk about how we
> hurt our users.

I have to say that while I tend to agree with you in general on this
one I think the boat already sailed.

For instance, what characters can follow an s/// expression and a m//
expression vary.

So, on one hand we have stuff like:

m/..../ge +1

which is a syntax error, but

m/..../le +1

is a valid expression, yet

s/...//ge +1

is interpreted as (s/...//ge) (+1).

Given how muddy the waters already are IMO this type of breakage is
only of interest to golfers. And is likely to involve only a mere
handful of scripts who probably aren't going to upgrade anyway. Anyone
sane puts a space after a regex and its modifiers anyway IMO.

Anyway, if we really are going to care about this now I really think
we aught to introduce deprecation warning when a character is
encountered immediately following a regex pattern (of any sort) that
is not a legal modifier so that we dont have to worry about it ever

And I will note that the introduction of /p was achieved without
anyone reporting any problems like this.


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

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