Perhaps a bit late, but ready at least, here is your latest P5P summary, full of last week's selected threads. Read about I/O problems and other language issues.
I'm not sure I understand fully the details, but : Dan Kogai, maintainer
of the Encode module, implemented a way to handle internal states, and
thus BOMs in encoded text. This was a consequence of bug report #22261,
about unrecognized BOM when reading a file larger than 1k with
encoding(UTF-16).
The bug : http://xrl.us/inj
What's a BOM : http://www.unicode.org/unicode/faq/utf_bom.html
sysread() do ?Nick Ing-Simmons and Gurusamy Sarathy have been working on the semantics
of the sysread() function and try to reach a consensus. Should it read
characters, or bytes ? That makes a difference when reading Unicode data,
or when doing CRLF line-ending translation. Moreover, the third edition of
the Camel Book and the perlfunc man page don't agree on this topic.
Jarkko Hietaniemi votes for bytes, and for characters when the filehandle
has been marked as UTF-8. But the common expectation seems to be that
sysread() should do what the C-level read() does, or, at least, that it
should always have byte semantics. That's the opinion of Nick, Graham
Barr, Ton Hospel, and others.
http://xrl.us/ink
John Peacock (still working on version objects!) wants to overload the
assignment operator. The subsequent thread explores the semantic
intricacies of this proposal. What happens when both sides of the
assignment are objects that overload = ?
Dan Sugalski says that overloading = is simply a tie, because
overloading as it stands now works on the value, while tying works on
the variable. But, in this case, how would work a tied variable holding a
blessed value ? Interesting thread.
http://xrl.us/inl
Stas Bekman asked for a way to disable the warning Constant subroutine redefined, which is produced by code like
use constant FOO => 1 ; use constant FOO => 2 ;
(That's bug id #22291.) This warning can't be disabled via the no
warnings pragma, and that's on purpose, because the FOO constant might
have been inlined in some code that uses it between the first and the
second redefinitions, leading to the dangerous situation where FOO !=
FOO. However, while developing mod_perl modules under Apache::Reload,
those warnings can be annoying. In this case the recommended way to shut
them up is to use a custom $SIG{__WARN__} handler.
http://xrl.us/inm
Alan Burlison asked for a (usable) general performance benchmark for perl. Nicholas Clark, while claiming that finding a useful benchmark seems to be a holy grail, suggests to use SpamAssassin with a fixed spam corpus.
Nicholas reported (as bug #22270) a strange behaviour of the tainting mechanism he didn't understand, and Spider Boardman provided a brilliant explanation of it, pointing his finger at the right place in the documentation.
http://xrl.us/inn
As a consequence from a discussion we had last month, Dave Mitchell added
a new warning, Useless localization, intended to warn at some usages of
local() on lvalues, that actually do nothing (e.g. local($x = 10).)
Jeff 'japhy' Pinyan did submit, a while ago, a patch to add a new
zero-width assertion \K to regular expressions. This was not
integrated, so he's asking for further advice. Your summarizer pointed him
at the old thread about this question, where Hugo suggested to turn this
patch into a built-in optimization.
A new alpha of MakeMaker, version 6.10_04, was released and integrated. Paul Johnson asked for a way to parse correctly a MANIFEST file (esp. now that MakeMaker can add a META.yml file to it) ; Michael G Schwern pointed him at ExtUtils::Manifest::maniread().
Jarkko released a new snapshot of maintperl.
This was yet another summary written by Rafael Garcia-Suarez. Weekly summaries like this very one are usually available on http://use.perl.org/ and via a mailing list, which subscription address is perl5-summary-subscribe@perl.org . Feedback welcome.