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Document qr overloading in perldelta
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1=head1 NAME
2
3[ Any text flagged as XXX needs to be processed before release. ]
4
5perldelta - what is new for perl v5.11.2
6
7=head1 DESCRIPTION
8
9This document describes differences between the 5.11.1 release and
10the 5.11.2 release.
11
12=head1 Notice
13
14XXX Unlikely to need this section.
15
16=head1 Incompatible Changes
17
d83f38d8 18=head2 Use of C<:=> to mean an empty attribute list is now deprecated.
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d83f38d8 20An accident of Perl's parser means that these constructions are all equivalent:
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22 my $pi := 4;
23 my $pi : = 4;
24 my $pi : = 4;
25
26with the C<:> being treated as the start of an attribute list, which ends
27before the C<=>. As whitespace is not significant here, all are parsed as an
28empty attribute list, hence all the above are equivalent to, and better written
29as
30
31 my $pi = 4;
32
33because no attribute processing is done for an empty list.
34
35As is, this means that C<:=> cannot be used as a new token, without silently
36changing the meaning of existing code. Hence that particular form is now
37deprecated, and will become a syntax error. If it is absolutely necessary to
38have empty attribute lists (for example, because of a code generator) the
39avoid the warning by adding a space before the C<=>.
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40
41=head1 Core Enhancements
42
43XXX New core language features go here. Summarise user-visible core language
44enhancements. Particularly prominent performance optimisations could go
45here, but most should go in the L</Performance Enhancements> section.
46
97352077
RGS
47=head2 qr overloading
48
49It is now possible to overload the C<qr//> operator, that is, conversion
50to regexp, like it was already possible to overload conversion to
51boolean, string or number of objects. It is invoked when an object
52appears on the right hand side of the C<=~> operator, or when it is
53interpolated into a regexp. See L<overload>.
54
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55=head1 New Platforms
56
57XXX List any platforms that this version of perl compiles on, that previous
58versions did not. These will either be enabled by new files in the F<hints/>
59directories, or new subdirectories and F<README> files at the top level of the
60source tree.
61
62=head1 Modules and Pragmata
63
64XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
65go here, in a list ordered by distribution name. Minimally it should be the
66module version, but it's more useful to the end user to give a paragraph's
67summary of the module's changes. In an ideal world, dual-life modules would
68have a F<Changes> file that could be cribbed.
69
70=head2 New Modules and Pragmata
71
72=over 4
73
74=item C<XXX>
75
76XXX
77
78=back
79
80=head2 Pragmata Changes
81
82=over 4
83
84=item C<XXX>
85
86XXX
87
88=back
89
90=head2 Updated Modules
91
92=over 4
93
94=item C<XXX>
95
96XXX
97
98=back
99
100=head1 Utility Changes
101
102XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go
103here. Most of these are built within the directories F<utils> and F<x2p>.
104
105=over 4
106
107=item F<XXX>
108
109XXX
110
111=back
112
113=head1 New Documentation
114
115XXX Changes which create B<new> files in F<pod/> go here.
116
117=over 4
118
119=item L<XXX>
120
121XXX
122
123=back
124
125=head1 Changes to Existing Documentation
126
127XXX Changes which significantly change existing files in F<pod/> go here.
128Any changes to F<pod/perldiag.pod> should go in L</New or Changed Diagnostics>.
129
130
131=head1 Performance Enhancements
132
133XXX Changes which enhance performance without changing behaviour go here. There
134may well be none in a stable release.
135
136=over 4
137
138=item *
139
140XXX
141
142=back
143
144=head1 Installation and Configuration Improvements
145
146XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
147go here.
148
149=head2 Configuration improvements
150
151XXX
152
153=head2 Compilation improvements
154
155XXX
156
157=head2 Platform Specific Changes
158
159=over 4
160
161=item XXX-some-platform
162
163XXX
164
165=back
166
167=head1 Selected Bug Fixes
168
169XXX Important bug fixes in the core language are summarised here.
170Bug fixes in files in F<ext/> and F<lib/> are best summarised in
171L</Modules and Pragmata>.
172
173=over 4
174
175=item *
176
177XXX
178
179=back
180
181=head1 New or Changed Diagnostics
182
183XXX New or changed warnings emitted by the core's C<C> code go here.
184
185=over 4
186
187=item C<XXX>
188
189XXX
190
191=back
192
193=head1 Changed Internals
194
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195=over 4
196
197=item *
198
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199C<Perl_pmflag> has been removed from the public API. Calling it now generates
200a deprecation warning, and it will be removed in a future release. Although
201listed as part of the API, it was never documented, and only ever used in
202F<toke.c>, and prior to 5.10, F<regcomp.c>. In core, it has been replaced by a
203static function.
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204
205=back
206
207=head1 New Tests
208
209XXX Changes which create B<new> files in F<t/> go here. Changes to
210existing files in F<t/> aren't worth summarising, although the bugs that
211they represent may be.
212
213=over 4
214
215=item F<XXX>
216
217XXX
218
219=back
220
221=head1 Known Problems
222
223XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
224tests that had to be C<TODO>ed for the release would be noted here, unless
225they were specific to a particular platform (see below).
226
227This is a list of some significant unfixed bugs, which are regressions
228from either 5.10.1 or 5.11.1.
229
230=over 4
231
232=item *
233
234XXX
235
236=back
237
238=head1 Deprecations
239
240XXX Add any new known deprecations here.
241
242The following items are now deprecated.
243
244=over 4
245
246=item *
247
248XXX
249
250=back
251
252=head1 Platform Specific Notes
253
254XXX Any changes specific to a particular platform. VMS and Win32 are the usual
255stars here. It's probably best to group changes under the same section layout
256as the main perldelta
257
258=head1 Obituary
259
260XXX If any significant core contributor has died, we've added a short obituary
261here.
262
263=head1 Acknowledgements
264
265XXX The list of people to thank goes here.
266
267
268=head1 Reporting Bugs
269
270If you find what you think is a bug, you might check the articles
271recently posted to the comp.lang.perl.misc newsgroup and the perl
272bug database at http://rt.perl.org/perlbug/ . There may also be
273information at http://www.perl.org/ , the Perl Home Page.
274
275If you believe you have an unreported bug, please run the B<perlbug>
276program included with your release. Be sure to trim your bug down
277to a tiny but sufficient test case. Your bug report, along with the
278output of C<perl -V>, will be sent off to perlbug@perl.org to be
279analysed by the Perl porting team.
280
281If the bug you are reporting has security implications, which make it
282inappropriate to send to a publicly archived mailing list, then please send
283it to perl5-security-report@perl.org. This points to a closed subscription
284unarchived mailing list, which includes all the core committers, who be able
285to help assess the impact of issues, figure out a resolution, and help
286co-ordinate the release of patches to mitigate or fix the problem across all
287platforms on which Perl is supported. Please only use this address for
288security issues in the Perl core, not for modules independently
289distributed on CPAN.
290
291=head1 SEE ALSO
292
293The F<Changes> file for an explanation of how to view exhaustive details
294on what changed.
295
296The F<INSTALL> file for how to build Perl.
297
298The F<README> file for general stuff.
299
300The F<Artistic> and F<Copying> files for copyright information.
301
302=cut