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Postings from December 2011
On Wed Oct 29 10:59:37 2003, ysth wrote:
> On Wed, Oct 29, 2003 at 08:08:37AM +0000, Graham Barr
> <gbarr@pobox.com> wrote:
> > On Oct 29, 2003, at 5:55, Yitzchak Scott-Thoennes wrote:
> > >On Wed, Oct 29, 2003 at 02:06:12AM -0000, "perl-5.8.0@ton.iguana.be
> > >(via RT)" <perlbug-followup@perl.org> wrote:
> > >>Sure, I can see what's going on here from an implementation point
> of
> > >>view, and the substr docs are pretty unspecific on this, so I
> can't
> > >>absolutely claim it as a bug. But it feels wrong to me to be able
> to
> > >>pull in stuff from outside the [0..3] range of the original string
> > >>into the substr window. Assigning something to a variable and have
> it
> > >>be different as a result is hardly normal lvalue behaviour.
> > >>(what happens to $a is as expected in all cases). I think it
> should
> > >>not only narrow or expand the original string as needed, but also
> > >>the range of the substr alias itself.
> > >
> > >Yes, I'd like to see this addressed for 5.10.0. Issues need to be
> > >worked out for how it should work with negative offset or length.
> >
> > Why would negative offsets be an issue ? When the LV is created any
> > negative offset is resolved and the LV is created with an absolute
> > offset and a length.
>
> That is how it is now, yes. But I can see a case for storing the
> negative
> values instead for situations like this:
>
> perl -wle'$x = "abcdef"; for (substr($x,-4,-1)) { chop$x; chop$x;
> print $_ }'
>
Unfortunately this never was addressed for 5.10.0. It is getting in the
way of other bugs, such as this:
sub myprint { print @_ }
print substr("", 2); # warning
myprint substr("", 2); # error
so I’m working on it for 5.15.6.
See
<http://www.nntp.perl.org/group/perl.perl5.porters/;msgid=63562EAE-84D6-48BF-8564-7AEE9504482D@cpan.org>.
(I’m adding it to this ticket mainly for future reference.)
--
Father Chrysostomos
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