This Week on perl5-porters (12-18 April 2004)
This was an RC-2 week, rich in events and discussions. Read about the
little-known dualvars, the always popular version strings, the set UID
perl, Unicode classes, and various other bugs.
Release Candidate 2
Nicholas Clark released a second RC of perl 5.8.4. The first RC was
backwards-incompatible with regard to the sperl and suidperl
executables, which must not be called directly anymore. It has been
decided that now, sperl and suidperl will be regular copies of perl
(that is, with regular permissions), while a new executable, setuidperl,
will be installed set-uid. This way, scripts that invoke
/usr/bin/s{,uid}perl won't break. (This is not a definitive plan;
moreover, the plan for bleadperl is still a bit unclear at this point.)
http://groups.google.com/groups?selm=20040414145128.GI676%40plum.flirble.org
Zero, but true
Zefram reports (as bug #28538) that a Math::BigInt object constructed
from the string literal "O but true" is not-a-number ("NaN"), instead of
being 0. It turns out that "O but true" is a string special-cased in the
perl internals: it doesn't trigger any warning about non-numerical
arguments. Similarly, Math::BigInt doesn't seem to have a very
consistent behaviour with dualvars -- scalar variables that have a
different numerical and string value.
http://groups.google.com/groups?selm=rt-3.0.8-28538-84956.7.86182961869045%40perl.org
A plea for an error variable
Stas Bekman wants to introduce a new convention about a standard error
variables, to be used by perl modules (logically equivalent to what $!
does for system errors.) Several names come up: $E::err, ${^ERROR}. This
variable would be used as a dualvar (numerical error code and error
message), as $! already is.
http://groups.google.com/groups?selm=407E4D97.6030702%40stason.org
Dual data dumping
While we're at dualvars, Zefram noticed (bug #28839) that Data::Dumper
doesn't output them correctly, and proposed a patch, which emits, in the
Data::Dumper output, code that uses Scalar::Util to reconstruct the
dualvar. Yves Orton replied that, given the high number of oddities one
can come up with in perl, dealing with dualvars was probably beyond the
scope of Data::Dumper, which is aimed, mostly, as dumping data.
http://groups.google.com/groups?selm=rt-3.0.8-28839-85361.16.3440539442637%40perl.org
More on version strings
David Dyck notices that the current version of ExtUtils::MakeMaker in
bleadperl is 6.21_02, which is parsed as 6.021002; and this causes
problems with modules that require a version of ExtUtils::MakeMaker
greater than or equal to 6.03. John Peacock explains that the underbar
is treated, for version parsing purposes, as a dot; although people
apparently expect it to be parsed more like a floating point version
number.
http://groups.google.com/groups?selm=Pine.LNX.4.51.0404120919230.16344%40dd.tc.fluke.com
Test diagnostics
Gisle Aas proposed a patch to the Test module, firstly to quote the
got/expected values when they contain weird characters, and secondly to
run diff(1) on those values when the environment variable PERL_TEST_DIFF
contains the path to a diff program.
Barrie Slaymaker points out that he wrote a module, Test::Differences,
to provide this diff functionality. Fergal Daly adds that one could use
Text::Diff if available instead of relying on an external program. Sean
M. Burke (who maintains Test) is pleased with this last idea.
http://groups.google.com/groups?selm=lrbrlwfdid.fsf%40caliper.activestate.com
Current package name weirdness
Michael G. Schwern reports a strange case where the __PACKAGE__ token
doesn't seem to have the value it should (across several files and
compilation units.) Further analysis is proposed, but no definitive
explanation: there may be a bug lurking in there.
http://groups.google.com/groups?selm=4933BB14-8D7B-11D8-AD86-0050E4A09F6A%40grantstreet.com
Unicode class names
Jeff Pinyan proposed a patch to extend the possibilities for the user to
define new Unicode classes; notably, to allow to reuse user-defined
Unicode classes in other ones, and to combine Unicode classes with the
logical operand "&" (in addition to the already supported "-", "+",
"!").
In Brief
Zefram remarked that a /...(\z/)?/ match doesn't populate $1 (bug
#28532). Hugo van der Sanden proposed a patch.
Dave Rolsky says that getting the source code of perl is too hard for
the novice porter, and proposes to send patches for http://dev.perl.org/
to fix this.
http://groups.google.com/groups?selm=Pine.LNX.4.58.0404150902340.17218%40urth.org
Jan Dubois fixed a buffer overflow in the Win32 build of perl (bug
#28525.)
Elizabeth Mattijsen found a bug in List::Util 1.08 (bug #28438):
returning from a "first" block segfaults. This used to produce a neat
error message.
http://groups.google.com/groups?selm=rt-3.0.8-28438-84380.11.3552556593606%40perl.org
About this summary
This summary was written by Rafael Garcia-Suarez. Weekly summaries are
published on http://use.perl.org/ and posted on a mailing list, which
subscription address is [EMAIL PROTECTED] Comments and
corrections welcome.
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