This week is to be filed in the category "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%40fre e.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
read() return value and EOFMichael 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
http://groups.google.com/groups?selm=rt-3.0.8-26670-78082.19.4315995467592%40per l.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.
Wouldn't that be half as fast? My guess is that you mean "50% faster" or equivalently, "faster by a factor of 1.5"