This Week on perl5-porters (23-29 September 2002)
This was a nice week, with lots of discussion, on various interesting
topics. Read on for strange bugs, strange fixes, strange error messages,
and as always, the ongoing efforts made to improve Perl 5.
"our(%hash)"
The construct "our(%hash)" appears to be a lot slower than "our %hash",
written without the parens (this is strange bug #17376). Yitzchak
Scott-Thoennes diagnosed the cause of this -- the parens trigger list
context, for no apparent purpose, hence the slowdown for large hashes
--, and he proposed new tests for it, with the appropriate failing tests
marked as TODO.
http://groups.google.com/groups?threadm=JNri9gzkgSBB092yn%40efn.org
Source code reorganization
Dave Mitchell proposed a huge patch to move all code related to the
handling of pads in new files, pod.h and pod.c. In addition to making
the code clearer, better organized, and more maintainable, Dave also
made the -DX debugging flag more comprehensive, and spotted a few places
where improvements could be made. This kind of reengineering effort is
rare enough to deserve to be underlined.
http://groups.google.com/groups?threadm=20020925234023.A20044%40fdgroup.com
Strange package names
Marc Lehmann discovered that when you declare a package as
package test::
then the "__PACKAGE__" token contains "test::" instead of "test". Mike
Guy says that this behavior is to be expected, and gives some examples.
http://groups.google.com/groups?threadm=rt-17571-38545.5.9750724209421%40bugs6.perl.org
Misleading warning
Arthur Bergman was puzzled by this warning : this one-liner
perl -we "close(STDOUT); open(F, qq{out.txt}) || die;"
says *Filehandle STDOUT opened only for input* (where out.txt is an
existing file.) In fact, once STDOUT has been closed, F gets the file
descriptor number of STDOUT. Hugo proposed to make the warning message
more explicit, like Filehandle STDOUT reopened as F only for input.
http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2002-09/msg00942.html
Memory usage
Elizabeth Mattijsen warns : *In order to determine ways of reducing
memory usage with perl, and with threaded perl in particular, I will be
annoying p5p with some memory benchmarks in the coming time.* She adds
also that every related message she'll send to p5p will have "[Memory]"
in the subject line.
http://groups.google.com/groups?threadm=4.2.0.58.20020925194559.04498d80%40mickey.dijkmat.nl
She started immediately to post a memory-related message, wondering why
the threads module overloads the "==" operator. A long thread was the
consequence of this first post, where we learned why a specific
comparison method is needed (in fact, the "==" operator on threads
compares thread ids to know whether two threads objects refer to the
same thread.)
http://groups.google.com/groups?threadm=4.2.0.58.20020925195132.028317c0%40mickey.dijkmat.nl
Making "charnames" more flexible
H.Merijn Brand proposed to extend the "charnames" pragma to allow
user-defined aliases for commonly used Unicode characters. Jarkko
discussed some implementation and API issues with the proposed
implementation. Everybody seems to agree now, but there is apparently no
definitive patch in.
http://groups.google.com/groups?threadm=20020926112635.BB02.H.M.BRAND%40hccnet.nl
Per-filehandle state variables
Eric Roode proposed to allow the I/O tuning variables ($,, $/, $\, $:
and $^L) to be set on a per-filehandle basis. Hugo provided insightful
advice about the proposed implementation and the potential problems.
http://groups.google.com/groups?threadm=20020927202723.GE584%40orwell.myxa.com
In brief
Ton Hospel reported an obscure regexp behavior, bug #17542. At least
perl golf is useful to uncover obscure bugs, isn't it ?
While we're at regexps, Barrie Slaymaker made the regexp engine dump
core via recursion, matching a quite long string (bug #17611).
And also, bug #17605 is about a change of behavior between perl 5.6.x
and 5.8.0 in the s///e operator, when the right side (the Perl
expression) is empty. Nobody commented.
Sudhindra Herle proposed to add to Pod::Html the ability to translate
links of form L<description|URL>. However Ronald J Kimball pointed out
that this syntax is not valid POD, according to the specs.
Marcel Gr�nauer (author of Getopt::Attribute, this very cool module you
should try) found a bug (#17587) in Attribute::Handlers, that wasn't
recognizing "shared" and "unique" as built-in attributes. Rafael
Garcia-Suarez provided a patch (will hopefully will end up on CPAN).
Jarkko Hietaniemi provided a new manpage, perl573delta, missing from
perl 5.8.0.
Andreas J. Koenig posted a documentation patch to the perlunicode
manpage, providing a bit of good advice about porting code from perl
5.6.x. A code example included in the patch quickly triggered a
discussion about the relative merits and readability of several perl
constructs. The original intent of the patch was lost somewhere in the
middle.
G. Rossati reported bug #17632, about stat() not behaving properly; it
turned out to be caused by File::stat, overriding the core function
stat(), but inconsistently (not checking for list context.) Hugo thinks
it's too late to change it to avoid difficult-to-spot breakages.
About this summary
This summary brought to you, as usual, by Rafael Garcia-Suarez. It's
also available via a mailing list, which subscription address is
[EMAIL PROTECTED] As usual, comments, corrections and
additions welcome. (Last minute -- for some reason Google sometimes
doesn't seem to return the whole thread. So I link sometimes to another
archive.)
