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Fix code-before-declaration problem in universal.c
[perl5.git] / pod / perldelta.pod
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1=encoding utf8
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3=head1 NAME
4
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5[ this is a template for a new perldelta file. Any text flagged as
6XXX needs to be processed before release. ]
4c793fe3 7
ee0887a9 8perldelta - what is new for perl v5.13.6
4c793fe3 9
ee0887a9 10=head1 DESCRIPTION
0c692eed 11
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12This document describes differences between the 5.13.5 release and
13the 5.13.6 release.
0c692eed 14
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15If you are upgrading from an earlier release such as 5.13.4, first read
16L<perl5135delta>, which describes differences between 5.13.4 and
175.13.5.
0c692eed 18
ee0887a9 19=head1 Notice
0c692eed 20
ee0887a9 21XXX Any important notices here
4c793fe3 22
ee0887a9 23=head1 Core Enhancements
85318b69 24
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25XXX New core language features go here. Summarise user-visible core language
26enhancements. Particularly prominent performance optimisations could go
27here, but most should go in the L</Performance Enhancements> section.
85318b69 28
ee0887a9 29[ List each enhancement as a =head2 entry ]
85318b69 30
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31=head2 C<(?^...)> regex construct added to signify default modifiers
32
33A caret (also called a "cirumflex accent") C<"^"> immediately following
34a C<"(?"> in a regular expression now means that the subexpression is to
35not inherit the surrounding modifiers such as C</i>, but to revert to the
36Perl defaults. Any modifiers following the caret override the defaults.
37
38The stringification of regular expressions now uses this notation. The
39main purpose of this is to allow tests that rely on the stringification
40to not have to change when new modifiers are added. See
41L<perlre/Extended Patterns>.
42
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43=head2 C<"d">, C<"l">, and C<"u"> regex modifiers added
44
45These modifiers are currently only available within a C<(?...)> construct.
46
47The C<"l"> modifier says to compile the regular expression as if it were
48in the scope of C<use locale>, even if it is not.
49
50The C<"u"> modifier currently does nothing.
51
52The C<"d"> modifier is used in the scope of C<use locale> to compile the
53regular expression as if it were not in that scope.
54See L<perlre/(?dlupimsx-imsx)>.
55
ee0887a9 56=head1 Security
85318b69 57
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58XXX Any security-related notices go here. In particular, any security
59vulnerabilities closed should be noted here rather than in the
60L</Selected Bug Fixes> section.
85318b69 61
ee0887a9 62[ List each security issue as a =head2 entry ]
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63
64=head1 Incompatible Changes
65
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66=head2 Stringification of regexes has changed
67
68Default regular expression modifiers are now notated by using
69C<(?^...)>. Code relying on the old stringification will fail. The
70purpose of this is so that when new modifiers are added, such code will
71not have to change, as the stringification will automatically
72incorporate the new modifiers.
73
74Code that needs to work properly with both old- and new-style regexes
75can use something like the following:
76
77 # Accept both old and new-style stringification
78 my $modifiers = (qr/foobar/ =~ /\Q(?^/) ? '^' : '-xism';
44428a46 79
fb85c044 80And then use C<$modifiers> instead of C<-xism>.
44428a46 81
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82=head2 Regular expressions retain their localeness when interpolated
83
84Regular expressions compiled under C<"use locale"> now retain this when
85interpolated into a new regular expression compiled outside a
86C<"use locale">, and vice-versa.
87
88Previously, a regular expression interpolated into another one inherited
89the localeness of the surrounding one, losing whatever state it
90originally had. This is considered a bug fix, but may trip up code that
91has come to rely on the incorrect behavior.
92
ee0887a9 93[ List each incompatible change as a =head2 entry ]
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94
95=head1 Deprecations
96
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97XXX Any deprecated features, syntax, modules etc. should be listed here.
98In particular, deprecated modules should be listed here even if they are
99listed as an updated module in the L</Modules and Pragmata> section.
85318b69 100
ee0887a9 101[ List each deprecation as a =head2 entry ]
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102
103=head1 Performance Enhancements
104
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105XXX Changes which enhance performance without changing behaviour go here. There
106may well be none in a stable release.
4c793fe3 107
ee0887a9 108[ List each enhancement as a =item entry ]
4c793fe3 109
ee0887a9 110=over 4
4c793fe3 111
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112=item *
113
ee0887a9 114XXX
e2babdfb 115
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116=back
117
118=head1 Modules and Pragmata
119
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120XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
121go here. If Module::CoreList is updated, generate an initial draft of the
122following sections using F<Porting/corelist-perldelta.pl>, which prints stub
123entries to STDOUT. Results can be pasted in place of the '=head2' entries
124below. A paragraph summary for important changes should then be added by hand.
125In an ideal world, dual-life modules would have a F<Changes> file that could be
126cribbed.
fc1418b7 127
ee0887a9 128[ Within each section, list entries as a =item entry ]
df91fef1 129
ee0887a9 130=head2 New Modules and Pragmata
ccb45ef4 131
ee0887a9 132=over 4
df91fef1 133
ee0887a9 134=item *
df91fef1 135
ee0887a9 136XXX
e2babdfb 137
ee0887a9 138=back
e2babdfb 139
ee0887a9 140=head2 Updated Modules and Pragmata
fc1418b7 141
ee0887a9 142=over 4
fc1418b7 143
ee0887a9 144=item *
e2babdfb 145
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146C<NEXT> has been upgraded from version 0.64 to 0.65.
147
148=item *
149
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150C<PathTools> has been upgraded from version 3.31_01 to 3.33.
151
152=item *
153
154C<Unicode::Normalize> has been upgraded from version 1.06 to 1.07
c9a84c8b 155
ee0887a9 156=back
c9a84c8b 157
ee0887a9 158=head2 Removed Modules and Pragmata
c9a84c8b 159
ee0887a9 160=over 4
4c793fe3 161
ee0887a9 162=item *
48c1efd2 163
ee0887a9 164XXX
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165
166=back
167
168=head1 Documentation
169
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170XXX Changes to files in F<pod/> go here. Consider grouping entries by
171file and be sure to link to the appropriate page, e.g. L<perlfunc>.
4c793fe3 172
ee0887a9 173=head2 New Documentation
4c793fe3 174
ee0887a9 175XXX Changes which create B<new> files in F<pod/> go here.
4c793fe3 176
ee0887a9 177=head3 L<XXX>
4c793fe3 178
ee0887a9 179XXX Description of the purpose of the new file here
4c793fe3 180
ee0887a9 181=head2 Changes to Existing Documentation
fc1418b7 182
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183XXX Changes which significantly change existing files in F<pod/> go here.
184However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
185section.
fc1418b7 186
ee0887a9 187=head3 L<XXX>
e2babdfb 188
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189=over 4
190
191=item *
192
ee0887a9 193XXX Description of the change here
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194
195=back
e2babdfb 196
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197=head1 Diagnostics
198
199The following additions or changes have been made to diagnostic output,
200including warnings and fatal error messages. For the complete list of
201diagnostic messages, see L<perldiag>.
202
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203XXX New or changed warnings emitted by the core's C<C> code go here. Also
204include any changes in L<perldiag> that reconcile it to the C<C> code.
4c793fe3 205
ee0887a9 206[ Within each section, list entries as a =item entry ]
4c793fe3 207
ee0887a9 208=head2 New Diagnostics
4c793fe3 209
ee0887a9 210XXX Newly added diagnostic messages go here
fc1418b7 211
ee0887a9 212=over 4
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213
214=item *
215
ee0887a9 216XXX
ebce6c40 217
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218=back
219
ee0887a9 220=head2 Changes to Existing Diagnostics
4c793fe3 221
ee0887a9 222XXX Changes (i.e. rewording) of diagnostic messages go here
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223
224=over 4
225
226=item *
227
ee0887a9 228XXX
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229
230=back
231
ee0887a9 232=head1 Utility Changes
4c793fe3 233
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234XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go
235here. Most of these are built within the directories F<utils> and F<x2p>.
4c793fe3 236
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237[ List utility changes as a =head3 entry for each utility and =item
238entries for each change
239Use L<XXX> with program names to get proper documentation linking. ]
fc1418b7 240
ee0887a9 241=head3 L<XXX>
fc1418b7 242
ee0887a9 243=over 4
4c793fe3 244
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245=item *
246
ee0887a9 247XXX
44428a46 248
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249=back
250
ee0887a9 251=head1 Configuration and Compilation
4c793fe3 252
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253XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
254go here. Any other changes to the Perl build process should be listed here.
255However, any platform-specific changes should be listed in the
256L</Platform Support> section, instead.
4c793fe3 257
ee0887a9 258[ List changes as a =item entry ].
4c793fe3 259
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260=over 4
261
262=item *
263
ee0887a9 264XXX
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265
266=back
4c793fe3 267
ee0887a9 268=head1 Testing
0c692eed 269
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270XXX Any significant changes to the testing of a freshly built perl should be
271listed here. Changes which create B<new> files in F<t/> go here as do any
272large changes to the testing harness (e.g. when parallel testing was added).
273Changes to existing files in F<t/> aren't worth summarising, although the bugs
274that they represent may be covered elsewhere.
0c692eed 275
ee0887a9 276[ List each test improvement as a =item entry ]
0c692eed 277
ee0887a9 278=over 4
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279
280=item *
281
ee0887a9 282XXX
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283
284=back
285
ee0887a9 286=head1 Platform Support
4c793fe3 287
ee0887a9 288XXX Any changes to platform support should be listed in the sections below.
4c793fe3 289
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290[ Within the sections, list each platform as a =item entry with specific
291changes as paragraphs below it. ]
4c793fe3 292
ee0887a9 293=head2 New Platforms
0c692eed 294
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295XXX List any platforms that this version of perl compiles on, that previous
296versions did not. These will either be enabled by new files in the F<hints/>
297directories, or new subdirectories and F<README> files at the top level of the
298source tree.
0c692eed 299
ee0887a9 300=over 4
0c692eed 301
ee0887a9 302=item XXX-some-platform
0c692eed 303
ee0887a9 304XXX
0c692eed 305
ee0887a9 306=back
0c692eed 307
ee0887a9 308=head2 Discontinued Platforms
4c793fe3 309
ee0887a9 310XXX List any platforms that this version of perl no longer compiles on.
8ebb9810 311
ee0887a9 312=over 4
8ebb9810 313
ee0887a9 314=item XXX-some-platform
48c1efd2 315
ee0887a9 316XXX
48c1efd2 317
ee0887a9 318=back
44428a46 319
ee0887a9 320=head2 Platform-Specific Notes
44428a46 321
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322XXX List any changes for specific platforms. This could include configuration
323and compilation changes or changes in portability/compatibility. However,
324changes within modules for platforms should generally be listed in the
325L</Modules and Pragmata> section.
f4beb78f 326
ee0887a9 327=over 4
f4beb78f 328
ee0887a9 329=item XXX-some-platform
ccb45ef4 330
ee0887a9 331XXX
ccb45ef4 332
ee0887a9 333=back
85318b69 334
ee0887a9 335=head1 Internal Changes
85318b69 336
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337XXX Changes which affect the interface available to C<XS> code go here.
338Other significant internal changes for future core maintainers should
339be noted as well.
85318b69 340
ee0887a9 341[ List each test improvement as a =item entry ]
80b6a949 342
ee0887a9 343=over 4
80b6a949 344
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345=item *
346
9de15fec 347See L</Regular expressions retain their localeness when interpolated>
e2babdfb 348
ee0887a9 349=back
e2babdfb 350
ee0887a9 351=head1 Selected Bug Fixes
e2babdfb 352
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353XXX Important bug fixes in the core language are summarised here.
354Bug fixes in files in F<ext/> and F<lib/> are best summarised in
355L</Modules and Pragmata>.
e2babdfb 356
ee0887a9 357[ List each fix as a =item entry ]
346e4e56 358
ee0887a9 359=over 4
346e4e56 360
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361=item *
362
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363A regular expression match in the right-hand side of a global substitution
364(C<s///g>) that is in the same scope will no longer cause match variables
365to have the wrong values on subsequent iterations. This can happen when an
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366array or hash subscript is interpolated in the right-hand side, as in
367C<s|(.)|@a{ print($1), /./ }|g>
368L<[perl #19078]|http://rt.perl.org/rt3//Public/Bug/Display.html?id=19078>.
369
370=item *
371
372Constant-folding used to cause
373
374 $text =~ ( 1 ? /phoo/ : /bear/)
375
376to turn into
377
378 $text =~ /phoo/
379
380at compile time. Now it correctly matches against C<$_>
381L<[perl #20444]|http://rt.perl.org/rt3//Public/Bug/Display.html?id=20444>.
78846812 382
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383=back
384
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385=head1 Known Problems
386
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387XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
388tests that had to be C<TODO>ed for the release would be noted here, unless
389they were specific to a particular platform (see below).
962fbe1d 390
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391This is a list of some significant unfixed bugs, which are regressions
392from either 5.XXX.XXX or 5.XXX.XXX.
962fbe1d 393
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394[ List each fix as a =item entry ]
395
396=over 4
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397
398=item *
399
ee0887a9 400XXX
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401
402=back
403
ee0887a9 404=head1 Obituary
4c793fe3 405
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406XXX If any significant core contributor has died, we've added a short obituary
407here.
0195fb5f 408
ee0887a9 409=head1 Acknowledgements
0195fb5f 410
ee0887a9 411XXX The list of people to thank goes here.
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412
413=head1 Reporting Bugs
414
415If you find what you think is a bug, you might check the articles
416recently posted to the comp.lang.perl.misc newsgroup and the perl
417bug database at http://rt.perl.org/perlbug/ . There may also be
418information at http://www.perl.org/ , the Perl Home Page.
419
420If you believe you have an unreported bug, please run the B<perlbug>
421program included with your release. Be sure to trim your bug down
422to a tiny but sufficient test case. Your bug report, along with the
423output of C<perl -V>, will be sent off to perlbug@perl.org to be
424analysed by the Perl porting team.
425
426If the bug you are reporting has security implications, which make it
427inappropriate to send to a publicly archived mailing list, then please send
ee0887a9 428it to perl5-security-report@perl.org. This points to a closed subscription
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429unarchived mailing list, which includes all the core committers, who be able
430to help assess the impact of issues, figure out a resolution, and help
431co-ordinate the release of patches to mitigate or fix the problem across all
ee0887a9 432platforms on which Perl is supported. Please only use this address for
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433security issues in the Perl core, not for modules independently
434distributed on CPAN.
435
436=head1 SEE ALSO
437
438The F<Changes> file for an explanation of how to view exhaustive details
439on what changed.
440
441The F<INSTALL> file for how to build Perl.
442
443The F<README> file for general stuff.
444
445The F<Artistic> and F<Copying> files for copyright information.
446
447=cut