5 perldelta - what is new for perl v5.13.2
9 This document describes differences between the 5.13.2 release and
12 If you are upgrading from an earlier release such as 5.10, first read
13 L<perl5120delta>, which describes differences between 5.10 and
18 XXX Any important notices here
20 =head1 Incompatible Changes
22 =head2 localised tied scalars are tied again.
24 The change in behaviour in 5.13.1 of localising tied scalar values has
25 been reverted to the existing 5.12.0 and earlier behaviour (the change for
26 arrays and hashes remains).
28 =head2 Naming fixes in Policy_sh.SH may invalidate Policy.sh
30 Several long-standing typos and naming confusions in Policy_sh.SH have
31 been fixed, standardizing on the variable names used in config.sh.
33 This will change the behavior of Policy.sh if you happen to have been
34 accidentally relying on the Policy.sh incorrect behavior. We'd appreciate
35 feedback from anyone using Policy.sh to be sure nothing is broken by
38 =head1 Core Enhancements
40 XXX New core language features go here. Summarise user-visible core language
41 enhancements. Particularly prominent performance optimisations could go
42 here, but most should go in the L</Performance Enhancements> section.
44 =head2 Non-destructive substitution
46 The substitution operator now supports a C</r> option that
47 copies the input variable, carries out the substitution on
48 the copy and returns the result. The original remains unmodified.
51 my $new = $old =~ s/cat/dog/r;
52 # $old is 'cat' and $new is 'dog'
54 This is particularly useful with C<map>. See L<perlop> for more examples
57 =head2 package block syntax
59 A package declaration can now contain a code block, in which case the
60 declaration is in scope only inside that block. So C<package Foo { ... }>
61 is precisely equivalent to C<{ package Foo; ... }>. It also works with
62 a version number in the declaration, as in C<package Foo 1.2 { ... }>.
63 See L<perlfunc> (434da3..36f77d, 702646).
65 =head2 perl -h no longer recommends -w
67 perl -h used to mark the -w option as recommended; since this option is
68 far less useful than it used to be due to lexical 'use warnings' and since
69 perl -h is primary a list and brief explanation of the command line switches,
70 the recommendation has now been removed (60eaec).
74 XXX List any platforms that this version of perl compiles on, that previous
75 versions did not. These will either be enabled by new files in the F<hints/>
76 directories, or new subdirectories and F<README> files at the top level of the
79 =head1 Modules and Pragmata
81 XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
82 go here. If Module::CoreList is updated, generate an initial draft of the
83 following sections using F<Porting/corelist-perldelta.pl>, which prints stub
84 entries to STDOUT. Results can be pasted in place of the '=head2' entries
85 below. A paragraph summary for important changes should then be added by hand.
86 In an ideal world, dual-life modules would have a F<Changes> file that could be
89 =head2 New Modules and Pragmata
91 =head2 Pragmata Changes
93 =head2 Updated Modules
95 Locale::Country, Locale::Language and Locale::Currency were updated from
96 3.12 to 3.13 of the Locale-Codes distribution to include locale code changes
99 =head2 Removed Modules and Pragmata
101 =head1 Utility Changes
103 XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go
104 here. Most of these are built within the directories F<utils> and F<x2p>.
114 =head1 New Documentation
116 XXX Changes which create B<new> files in F<pod/> go here.
126 =head1 Changes to Existing Documentation
128 XXX Changes which significantly change existing files in F<pod/> go here.
129 Any changes to F<pod/perldiag.pod> should go in L</New or Changed Diagnostics>.
131 =head2 Replace wrong tr/// table in perlebcdic.pod
133 perlebcdic.pod contains a helpful table to use in tr/// to convert
134 between EBCDIC and Latin1/ASCII. Unfortunately, the table was the
135 inverse of the one it describes, though the code that used the table
136 worked correctly for the specific example given.
138 The table has been changed to its inverse, and the sample code changed
139 to correspond, as this is easier for the person trying to follow the
140 instructions since deriving the old table is somewhat more complicated.
142 The table has also been changed to hex from octal, as that is more the norm
143 these days, and the recipes in the pod altered to print out leading
144 zeros to make all the values the same length, as the table that they can
145 generate has them (5f26d5).
147 =head2 Document tricks for user-defined casing
149 perlunicode.pod now contains an explanation of how to override, mangle
150 and otherwise tweak the way perl handles upper, lower and other case
151 conversions on unicode data, and how to provide scoped changes to alter
152 one's own code's behaviour without stomping on anybody else (71648f).
154 =head2 INSTALL explicitly states the requirement for C89
156 This was already true but it's now Officially Stated For The Record (51eec7).
158 =head2 No longer advertise Math::TrulyRandom
160 This module hasn't been updated since 1996 so we can't recommend it any more
163 =head1 Performance Enhancements
165 Only allocate entries for @_ on demand - this not only saves memory per
166 subroutine defined but should hopefully improve COW behaviour (77bac2).
168 Multiple small improvements to threads:
174 Change the internal structured of thread->params from an SV (RV) to an AV
175 - so we now pass around and store the array directly, rather than creating,
176 holding and dereferencing a reference to it (78b7eff).
180 Change S_ithread_create() params from a single AV* to a pair of SV** pointers.
181 This saves creating, duplicating and freeing and AV, which is only ever used for
182 an internal calling convention (4cf5ea).
186 Remove redundant hv_exists() calls from ithread_create()'s spec parser (b1faab).
190 Skip unnecessary newAV() in ithread_create() (39f3f7).
194 Avoid duping pads created for recursion since there's no point pre-allocating
195 the same memory in the new thread (6de654).
199 Eliminated xhv_fill from struct xpvhv: This saves 1 IV per hash and on some
200 systems will cause struct xpvhv to become cache aligned. To avoid this
201 memory saving causing a slowdown elsewhere, boolean use of HvFILL now
202 calls HvTOTALKEYS instead (which is equivalent) - so while the fill data when
203 actually required is now calculated on demand, the cases when this needs to
204 be done should be few and far between (f4431c .. fcd245).
206 The foldEQ_utf8 API function for case-insensitive comparison of strings (which
207 is used heavily by the regexp engine) was substantially refactored and
208 optimised - and its documentation much improved as a free bonus gift
211 =head1 Installation and Configuration Improvements
213 XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
216 =head2 Configuration improvements
220 =head2 Compilation improvements
222 Fix CCINCDIR and CCLIBDIR for mingw64 cross compiler to correctly be under
223 $(CCHOME)\mingw\include and \lib rather than immediately below $(CCHOME).
225 This means the 'incpath', 'libpth', 'ldflags', 'lddlflags' and
226 'ldflags_nolargefiles' values in Config.pm and Config_heavy.pl are now
227 set correctly (23ae7f).
229 =head2 Platform Specific Changes
233 =item XXX-some-platform
239 =head1 Selected Bug Fixes
241 Timely cleanup of SVs that are cloned into a new thread but then discovered
242 to be orphaned (i.e. their owners are -not- cloned) (e42956)
244 Don't accidentally clone lexicals in scope within active stack frames in
245 the parent when creating a child thread (RT #73086) (05d04d).
247 Avoid loading feature.pm when 'no 5.13.2;' or similar is encountered (faee19).
249 Trap invalid use of SvIVX on SVt_REGEXP when assertions are on (e77da3)
251 Don't stamp on $DB::single, $DB::trace and $DB::signal if they already have
252 values when $^P is assigned to (RT #72422) (4c0f30).
254 chop now correctly handles perl's extended UTF-8 (RT #73246) (65ab92)
256 Defer signal handling when shared SV locks are held to avoid deadlocks
257 (RT #74868) (65c742).
259 glob() no longer crashes when %File::Glob:: is empty and CORE::GLOBAL::glob
260 isn't present (4984aa).
262 perlbug now always permits the sender address to be changed before sending
263 - if you were having trouble sending bug reports before now, this should
264 fix it, we hope (e6eb90).
270 Overloading now works properly in conjunction with tied variables. What
271 formerly happened was that most ops checked their arguments for overloading
272 I<before> checking for magic, so for example an overloaded object returned
273 by a tied array access would usually be treated as not overloaded
274 (RT #57012) (6f1401, ed3b9b, 6a5f8c .. 24328f).
278 Independently, a bug was fixed that prevented $tied->() from always calling
279 FETCH correctly (RT #8438) (7c7501)
281 =head1 New or Changed Diagnostics
283 XXX New or changed warnings emitted by the core's C<C> code go here.
293 =head1 Changed Internals
295 XXX Changes which affect the interface available to C<XS> code go here.
301 The C<find_rundefsvoffset> function has been deprecated. It appeared that
302 its design was insufficient to reliably get the lexical C<$_> at run-time.
304 Use the new C<find_rundefsv> function or the C<UNDERBAR> macro instead.
305 They directly return the right SV representing C<$_>, whether it's lexical
306 or dynamic (789bd8 .. 03d5bc).
310 The following new functions or macros have been added to the public API:
311 C<SvNV_nomg>, C<sv_2nv_flags>, C<find_rundefsv>.
315 The C<UNDERBAR> macro now calls C<find_rundefsv>. C<dUNDERBAR> is now a
316 noop but should still be used to ensure past and future compatibility.
320 The ibcmp_* functions have been renamed and are now called foldEQ,
321 foldEQ_locale and foldEQ_utf8 (e6226b).
325 The ibcmp_* functions have been renamed and are now called foldEQ,
326 foldEQ_locale and foldEQ_utf8 (e6226b).
332 XXX Changes which create B<new> files in F<t/> go here. Changes to
333 existing files in F<t/> aren't worth summarising, although the bugs that
334 they represent may be.
344 =head1 Known Problems
346 XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
347 tests that had to be C<TODO>ed for the release would be noted here, unless
348 they were specific to a particular platform (see below).
350 This is a list of some significant unfixed bugs, which are regressions
351 from either 5.XXX.XXX or 5.XXX.XXX.
363 XXX Add any new known deprecations here.
365 The following items are now deprecated.
371 Omitting a space between a regex pattern or pattern modifiers and the following
372 word is deprecated. For example, C<< m/foo/sand $bar >> will still be parsed
373 as C<< m/foo/s and $bar >> but will issue a warning.
377 =head1 Platform Specific Notes
379 XXX Any changes specific to a particular platform. VMS and Win32 are the usual
380 stars here. It's probably best to group changes under the same section layout
381 as the main perldelta
385 XXX If any significant core contributor has died, we've added a short obituary
388 =head1 Acknowledgements
390 XXX The list of people to thank goes here.
392 Your humble release manager would like to specifically call out
393 Karl Williamson for making the tests a better place to be, and Shlomi
394 Fish for a passel of tiny incremental docfixes of the sort that don't get
397 =head1 Reporting Bugs
399 If you find what you think is a bug, you might check the articles
400 recently posted to the comp.lang.perl.misc newsgroup and the perl
401 bug database at http://rt.perl.org/perlbug/ . There may also be
402 information at http://www.perl.org/ , the Perl Home Page.
404 If you believe you have an unreported bug, please run the B<perlbug>
405 program included with your release. Be sure to trim your bug down
406 to a tiny but sufficient test case. Your bug report, along with the
407 output of C<perl -V>, will be sent off to perlbug@perl.org to be
408 analysed by the Perl porting team.
410 If the bug you are reporting has security implications, which make it
411 inappropriate to send to a publicly archived mailing list, then please send
412 it to perl5-security-report@perl.org. This points to a closed subscription
413 unarchived mailing list, which includes all the core committers, who be able
414 to help assess the impact of issues, figure out a resolution, and help
415 co-ordinate the release of patches to mitigate or fix the problem across all
416 platforms on which Perl is supported. Please only use this address for
417 security issues in the Perl core, not for modules independently
422 The F<Changes> file for an explanation of how to view exhaustive details
425 The F<INSTALL> file for how to build Perl.
427 The F<README> file for general stuff.
429 The F<Artistic> and F<Copying> files for copyright information.