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perl5112delta(1)       Perl Programmers Reference Guide       perl5112delta(1)




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 $[.


Performance Enhancements

       o   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

       o   "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.



perl v5.12.0                      2010-01-18                  perl5112delta(1)

perl 5.12.0 - Generated Thu Apr 29 06:33:26 CDT 2010
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