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Postings from August 2010
* karl williamson <public@khwilliamson.com> [2010-08-05 19:25]:
> Aristotle Pagaltzis wrote:
> >* karl williamson <public@khwilliamson.com> [2010-08-04 15:40]:
> >>FWIW, I have given this some thought, and came to the
> >>conclusion that Perl is almost certainly never going to
> >>change the defaults, because of the backward compatibility
> >>issues.
> >
> >Yet you *are* changing the past default right now, *in spite*
> >of back compat issues… :-)
>
> I'm not sure I understand. The default options remain the same.
> Ben made the point in your quote above that by doing this now
> when we are pretty much agreed that something should be done
> will cause this to likely be the last time adding a flag would
> cause backward compatibility issues.
If the default is not allowed to change again, then we gain
nothing from `(?~:)`.
Right now, the problem is that the default is changing, such that
`(?-xism)` is not an accurate representation of it.
This is caused by the fact that we are introducing a flag that
*requires* a choice of default.
What happens if we run into this situation again in the future?
If the meaning of `(?~:)` is not allowed to change, then it will
no longer be an accurate representation, so patterns will have to
stringify to `(?~Xy:)`.
And thus we get the exact same breakage that we are having now
with `(?-xism)`.
(Personally I would rather skip the entire discussion and train
people to do
( my $re_defaults = "" . qr/ / ) =~ s/ //g;
and use *that* instead of hardcoding *either* `(?-xism:)` *or*
`(?~:)` *or* anything else, because that’s guaranteed to yield
the right default stringification now and forever.)
Regards,
--
Aristotle Pagaltzis // <http://plasmasturm.org/>
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