NAME¶
perl5112delta - what is new for perl v5.11.2
DESCRIPTION¶
This document describes differences between the 5.11.1 release and the 5.11.2
release.
Core Enhancements¶
qr overloading¶
It is now possible to overload the "qr//" operator, that is,
conversion to regexp, like it was already possible to overload conversion to
boolean, string or number of objects. It is invoked when an object appears on
the right hand side of the "=~" operator, or when it is interpolated
into a regexp. See overload.
Pluggable keywords¶
Extension modules can now cleanly hook into the Perl parser to define new kinds
of keyword-headed expression and compound statement. The syntax following the
keyword is defined entirely by the extension. This allow a completely non-Perl
sublanguage to be parsed inline, with the right ops cleanly generated. This
feature is currently considered experimental.
See "PL_keyword_plugin" in perlapi for the mechanism. The Perl core
source distribution also includes a new module XS::APItest::KeywordRPN, which
implements reverse Polish notation arithmetic via pluggable keywords. This
module is mainly used for test purposes, and is not normally installed, but
also serves as an example of how to use the new mechanism.
APIs for more internals¶
The lowest layers of the lexer and parts of the pad system now have C APIs
available to XS extensions. These are necessary to support proper use of
pluggable keywords, but have other uses too. The new APIs are experimental,
and only cover a small proportion of what would be necessary to take full
advantage of the core's facilities in these areas. It is intended that the
Perl 5.13 development cycle will see the addition of a full range of clean,
supported interfaces.
Overridable function lookup¶
Where an extension module hooks the creation of rv2cv ops to modify the
subroutine lookup process, this now works correctly for bareword subroutine
calls. This means that prototypes on subroutines referenced this way will be
processed correctly. (Previously bareword subroutine names were initially
looked up, for parsing purposes, by an unhookable mechanism, so extensions
could only properly influence subroutine names that appeared with an
"&" sigil.)
Modules and Pragmata¶
New Modules and Pragmata¶
- "legacy"
- Preserves legacy behaviors or enable new non-default
behaviors. Currently the only behaviour concerns semantics for the 128
characters on ASCII systems that have the 8th bit set.
Pragmata Changes¶
- "diagnostics"
- Supports %.0f formatting internally.
- "overload"
- Allow overloading of 'qr'.
Updated Modules¶
- "B::Concise"
- Optimize reversing an array in-place, avoid using defined
%hash in core code and tests.
- "B::Deparse"
- Teach B::Deparse about in-place reverse.
- "Carp"
- Refine Carp caller() fix and add tests.
- "Compress::Zlib"
- Updated to 2.022.
- "CPANPLUS"
- Updated to 0.89_09.
- "Encode"
- Updated to 2.38.
- "ExtUtils::CBuilder"
- Updated to 0.27.
- "Env"
- Add EXISTS and DELETE methods to Env.pm.
- "File::Fetch"
- Updated to 0.22.
- "I8N::Langinfo"
- Correctly document export of I18N::Langinfo.
- "I8N::LangTags"
- In I18N::LangTags::Detect, avoid using defined @array and
defined %hash.
- "IO::Compress"
- Updated to 2.022.
- "IPC::Cmd"
- Updated to 0.54.
- "List::Util"
- Updated to 1.22.
- "Locale::Maketext"
- In Locale::Maketext, avoid using defined @array and defined
%hash. Convert the odd Locale::Maketext test out from Test to
Test::More.
- "Module::Build"
- Updated to 0.35_08.
- "Module::CoreList"
- Implemented is_deprecated().
- "Pod::Simple"
- Updated to 3.10.
- "Scalar::Util"
- Updated to 1.22.
- "Switch"
- Updated to 2.16.
Utility Changes¶
- a2p
- Fixed bugs with the match() operator in list
context, remove mention of $[.
- •
- Reversing an array to itself (as in "@a = reverse
@a") in void context now happens in-place and is several orders of
magnitude faster than it used to be. It will also preserve non-existent
elements whenever possible, i.e. for non magical arrays or tied arrays
with "EXISTS" and "DELETE" methods.
New or Changed Diagnostics¶
Several new diagnostics, see perldiag for details.
- "Bad plugin affecting keyword '%s'"
- "gmtime(%.0f) too large"
- "Lexing code attempted to stuff non-Latin-1 character
into Latin-1 input"
- "Lexing code internal error (%s)"
- "localtime(%.0f) too large"
- "Overloaded dereference did not return a
reference"
- "Overloaded qr did not return a REGEXP"
- "Perl_pmflag() is deprecated, and will be removed from
the XS API"
One diagnostic has been removed:
- "Runaway format"
Changed Internals¶
- •
- "Perl_pmflag" has been removed from the public
API. Calling it now generates a deprecation warning, and it will be
removed in a future release. Although listed as part of the API, it was
never documented, and only ever used in toke.c, and prior to 5.10,
regcomp.c. In core, it has been replaced by a static function.
New Tests¶
- t/op/while_readdir.t
- Test that a bare readdir in while loop sets $_.
Known Problems¶
- Known test failures on VMS
- Perl 5.11.2 fails a small set of core and CPAN tests as of
this release. With luck, that'll be sorted out for 5.11.3.
Deprecations¶
The following items are now deprecated.
Use of ":=" to mean an empty attribute list is now
deprecated.¶
An accident of Perl's parser meant that these constructions were all equivalent:
my $pi := 4;
my $pi : = 4;
my $pi : = 4;
with the ":" being treated as the start of an attribute list, which
ends before the "=". As whitespace is not significant here, all are
parsed as an empty attribute list, hence all the above are equivalent to, and
better written as
my $pi = 4;
because no attribute processing is done for an empty list.
As is, this meant that ":=" cannot be used as a new token, without
silently changing the meaning of existing code. Hence that particular form is
now deprecated, and will become a syntax error. If it is absolutely necessary
to have empty attribute lists (for example, because of a code generator) then
avoid the warning by adding a space before the "=".
Acknowledgements¶
Perl 5.11.2 represents approximately 3 weeks development since Perl 5.11.1 and
contains 29,992 lines of changes across 458 files from 38 authors and
committers:
Abhijit Menon-Sen, Abigail, Ben Morrow, Bo Borgerson, Brad Gilbert, Bram, Chris
Williams, Craig A. Berry, Daniel Frederick Crisman, Dave Rolsky, David E.
Wheeler, David Golden, Eric Brine, Father Chrysostomos, Frank Wiegand, Gerard
Goossen, Gisle Aas, Graham Barr, Harmen, H.Merijn Brand, Jan Dubois, Jerry D.
Hedden, Jesse Vincent, Karl Williamson, Kevin Ryde, Leon Brocard, Nicholas
Clark, Paul Marquess, Philippe Bruhat, Rafael Garcia-Suarez, Sisyphus, Steffen
Mueller, Steve Hay, Steve Peters, Vincent Pit, Yuval Kogman, Yves Orton, and
Zefram.
Many of the changes included in this version originated in the CPAN modules
included in Perl's core. We're grateful to the entire CPAN community for
helping Perl to flourish.
Reporting Bugs¶
If you find what you think is a bug, you might check the articles recently
posted to the comp.lang.perl.misc newsgroup and the perl bug database at
http://rt.perl.org/perlbug/ . There may also be information at
http://www.perl.org/ , the Perl Home Page.
If you believe you have an unreported bug, please run the
perlbug program
included with your release. Be sure to trim your bug down to a tiny but
sufficient test case. Your bug report, along with the output of "perl
-V", will be sent off to perlbug@perl.org to be analysed by the Perl
porting team.
If the bug you are reporting has security implications, which make it
inappropriate to send to a publicly archived mailing list, then please send it
to perl5-security-report@perl.org. This points to a closed subscription
unarchived mailing list, which includes all the core committers, who be able
to help assess the impact of issues, figure out a resolution, and help
co-ordinate the release of patches to mitigate or fix the problem across all
platforms on which Perl is supported. Please only use this address for
security issues in the Perl core, not for modules independently distributed on
CPAN.
SEE ALSO¶
The
Changes file for an explanation of how to view exhaustive details on
what changed.
The
INSTALL file for how to build Perl.
The
README file for general stuff.
The
Artistic and
Copying files for copyright information.