This week is to be filed in the categpry "busy" for the Perl 5 porters. Read about new optimisations, new ideas, new warnings, bugs, fixes, and other future plans for the next major version of Per 5.
Paul Johnson revamped the internal OP structure so that optrees now take less memory (while the speed impact is not mesureable.) This is going only in bleadperl, because, obviously, it breaks binary compatibility.
http://groups.google.com/groups?selm=20040221174213.5c39a8b5.rgarciasuarez%40free.fr
Dave Mitchell continues his series of impressive patches by extending the AELEMFAST optimisation to lexical arrays. This optimisation was already in place for global arrays, to access an element where the index is an integer constant between 0 and 255. As a result, access to fixed elements of lexical arrays seems to be faster by a factor of 50%.
http://groups.google.com/groups?selm=20040222160435.GA20408%40fdisolutions.com
Michael Bell reports (as bug #26787) that read() can return 0 on Linux even when not at end-of-file, when under a high system load. It is a bug in perl, or a misfeature, or a bug in Linux? Should read() return undef on EOF?
http://groups.google.com/groups?selm=rt-3.0.8-26787-78336.2.2498005290219%40perl.org
Stas Bekman reports (bug #26670) that perl (with the PerlIO implementation, default since 5.8.0) seems to handle dup(2) badly when some STD streams are closed, emitting an obscure warning Filehandle STDOUT reopened only for input (or the inverse). Nick Ing-Simmons points out that this is in fact expected behaviour: since STDOUT was closed, the next open() reuses filehandle number 1, which is, by definition, STDOUT (in perl and in C); so perl, here, warns about a potential bogus situation. Nick's advice is to reopen a closed STD handle to /dev/null.
http://groups.google.com/groups?selm=rt-3.0.8-26670-78082.19.4315995467592%40perl.org
Ton Hospel notices (bug #26866) that the autovivification of hash and array references does not seem to happen consistently. For example, this is valid:
$u = undef; $x = $u->{foo}
but this dies with a fatal error:
$x = ($u=undef)->{foo}
Nicholas Clark points out that this is probably the same problem that was reported as bug #18635.
http://groups.google.com/groups?selm=c101e9$jf8$1%40post.home.lunix
$_Continuing a thread from last week, a proposal to extend the prototype syntax was discussed: a new prototype character, _, could stand for optional value that defaults to $_. For example, a function that takes a list as a parameter, but that uses $_ if passed the empty list, could have the prototype sub mychomp(_@). However, this implies that the prototypes of built-ins would change.
The complete thread:
http://groups.google.com/groups?selm=20040206164438.GK19932%40c3.convolution.nl
The dubious construct
my $foo = $bar if $condition;
(and other equivalent ones) now produces a deprecation warning, thanks to Dave Mitchell. (See our previous episodes for details).
Jamie Lokier reports (bug #26909) that in a (?{...}) regular expression block, lexical variables are captured, just like in closures, but without warning the user as of 5.8.0. This lack of warning is fixed in recent perls.
He also reported (as bug #26910) that use strict 'vars' doesn't seem to be active in (?{...}) blocks.
Sean O'Rourke reported that calling a subroutine f() recursively with goto &f leaks memory, and suggests that it may come from lexicals not being freed. (Bug #26959.)
Rafael announced that he plans to make a new developement release of perl, 5.9.1, in March.
Meanwhile, Leon Brocard released perl 5.005_04 RC2.
http://groups.google.com/groups?selm=20040219142651.GA31294%40kanga.astray.com
Brendan O'Dea sent a batch of patches that he applied to the Debian 5.8.3-2 release of perl.
http://groups.google.com/groups?selm=20040215122717.GA26812%40londo.c47.org
Russ Allbery released Term::ANSIColor 1.08. MIME::Base64 3.00, which was released a while ago, was also integrated into the perl distribution.
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 perl5-summary-subscribe@perl.org. (I've been trying to use gmane (http://news.gmane.org/) as a message archive, but it's horribly slow.) Corrections and comments are welcome.