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42e73e1c 1=head1 NAME
2
3perlexperiment - A listing of experimental features in Perl
4
5=head1 DESCRIPTION
6
7This document lists the current and past experimental features in the perl
d1558b3e 8core. Although all of these are documented with their appropriate topics,
42e73e1c 9this succinct listing gives you an overview and basic facts about their
10status.
11
fe8d2675 12So far we've merely tried to find and list the experimental features and infer
d1558b3e 13their inception, versions, etc. There's a lot of speculation here.
42e73e1c 14
15=head2 Current experiments
16
17=over 8
18
42e73e1c 19=item C<our> can now have an experimental optional attribute C<unique>
20
21Introduced in Perl 5.8.0
22
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23Deprecated in Perl 5.10.0
24
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25The ticket for this feature is
26L<[perl #119313]|https://rt.perl.org/rt3/Ticket/Display.html?id=119313>.
27
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28=item Smart match (C<~~>)
29
30Introduced in Perl 5.10.0
31
32Modified in Perl 5.10.1, 5.12.0
33
34Using this feature triggers warnings in the category
35C<experimental::smartmatch>.
36
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37The ticket for this feature is
38L<[perl #119317]|https://rt.perl.org/rt3/Ticket/Display.html?id=119317>.
39
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40=item Pluggable keywords
41
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42The ticket for this feature is
43L<[perl #119455]|https://rt.perl.org/rt3/Ticket/Display.html?id=119455>.
44
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45See L<perlapi/PL_keyword_plugin> for the mechanism.
46
47Introduced in: Perl 5.11.2
48
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49=item Lexical subroutines
50
51Introduced in: Perl 5.18
52
53See also: L<perlsub/Lexical Subroutines>
54
55Using this feature triggers warnings in the category
56C<experimental::lexical_subs>.
57
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58The ticket for this feature is
59L<[perl #120085]|https://rt.perl.org/rt3/Ticket/Display.html?id=120085>.
60
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61=item Regular Expression Set Operations
62
63Introduced in: Perl 5.18
64
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65The ticket for this feature is
66L<[perl #119451]|https://rt.perl.org/rt3/Ticket/Display.html?id=119451>.
67
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68See also: L<perlrecharclass/Extended Bracketed Character Classes>
69
70Using this feature triggers warnings in the category
71C<experimental::regex_sets>.
72
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73=item Subroutine signatures
74
75Introduced in Perl 5.20.0
76
77Using this feature triggers warnings in the category
78C<experimental::signatures>.
79
80The ticket for this feature is
81L<[perl #121481]|https://rt.perl.org/Ticket/Display.html?id=121481>.
82
baabe3fb 83=item Aliasing via reference
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84
85Introduced in Perl 5.22.0
86
87Using this feature triggers warnings in the category
baabe3fb 88C<experimental::refaliasing>.
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89
90The ticket for this feature is
91L<[perl #122947]|https://rt.perl.org/rt3/Ticket/Display.html?id=122947>.
92
93See also: L<perlref/Assigning to References>
94
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95=item The "const" attribute
96
97Introduced in Perl 5.22.0
98
99Using this feature triggers warnings in the category
100C<experimental::const_attr>.
101
102The ticket for this feature is
1e50fc51 103L<[perl #123630]|https://rt.perl.org/rt3/Ticket/Display.html?id=123630>.
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104
105See also: L<perlsub/Constant Functions>
106
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107=item use re 'strict';
108
109Introduced in Perl 5.22.0
110
111Using this feature triggers warnings in the category
112C<experimental::re_strict>.
113
114See L<re/'strict' mode>
115
6207d112
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116=item String- and number-specific bitwise operators
117
118Introduced in: Perl 5.22.0
119
120See also: L<perlop/Bitwise String Operators>
121
122Using this feature triggers warnings in the category
123C<experimental::bitwise>.
124
125The ticket for this feature is
0fe81779 126L<[perl #123707]|https://rt.perl.org/rt3/Ticket/Display.html?id=123707>.
6207d112 127
706c19b7 128=item The <:win32> IO pseudolayer
42e73e1c 129
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130The ticket for this feature is
131L<[perl #119453]|https://rt.perl.org/rt3/Ticket/Display.html?id=119453>.
132
42e73e1c 133See also L<perlrun>
134
42e73e1c 135=item There is an C<installhtml> target in the Makefile.
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136
137The ticket for this feature is
138L<[perl #116487]|https://rt.perl.org/rt3/Ticket/Display.html?id=116487>.
42e73e1c 139
140=item Unicode in Perl on EBCDIC
141
42e73e1c 142=back
143
144=head2 Accepted features
145
146These features were so wildly successful and played so well with others that
147we decided to remove their experimental status and admit them as full, stable
51c34fa4 148features in the world of Perl, lavishing all the benefits and luxuries thereof.
42e73e1c 149They are also awarded +5 Stability and +3 Charisma.
150
151=over 8
152
51c34fa4 153=item 64-bit support
42e73e1c 154
51c34fa4 155Introduced in Perl 5.005
fe8d2675 156
51c34fa4 157=item die accepts a reference
fe8d2675 158
51c34fa4 159Introduced in Perl 5.005
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160
161=item DB module
162
163Introduced in Perl 5.6.0
164
165See also L<perldebug>, L<perldebtut>
166
167=item Weak references
168
169Introduced in Perl 5.6.0
170
171=item Internal file glob
172
173Introduced in Perl 5.6.0
174
51c34fa4 175=item fork() emulation
fe8d2675 176
51c34fa4 177Introduced in Perl 5.6.1
fe8d2675 178
51c34fa4 179See also L<perlfork>
fe8d2675 180
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181=item -Dusemultiplicity -Duseithreads
182
183Introduced in Perl 5.6.0
184
185Accepted in Perl 5.8.0
186
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187=item Support for long doubles
188
189Introduced in Perl 5.6.0
190
191Accepted in Perl 5.8.1
192
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193=item The C<\N> regex character class
194
195The C<\N> character class, not to be confused with the named character
196sequence C<\N{NAME}>, denotes any non-newline character in a regular
197expression.
198
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199Introduced in Perl 5.12
200
201Exact version of acceptance unclear, but no later than Perl 5.18.
fe8d2675 202
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203=item C<(?{code})> and C<(??{ code })>
204
205Introduced in Perl 5.6.0
206
207Accepted in Perl 5.20.0
208
209See also L<perlre>
210
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211=item Linux abstract Unix domain sockets
212
213Introduced in Perl 5.9.2
214
215Accepted before Perl 5.20.0. The Socket library is now primarily maintained
216on CPAN, rather than in the perl core.
217
218See also L<Socket>
219
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220=item Lvalue subroutines
221
222Introduced in Perl 5.6.0
223
224Accepted in Perl 5.20.0
225
226See also L<perlsub>
227
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228=item Backtracking control verbs
229
230C<(*ACCEPT)>
231
232Introduced in: Perl 5.10
233
234Accepted in Perl 5.20.0
235
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236=item The <:pop> IO pseudolayer
237
238See also L<perlrun>
239
240Accepted in Perl 5.20.0
241
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242=item C<\s> in regexp matches vertical tab
243
244Accepted in Perl 5.22.0
245
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246=item Postfix dereference syntax
247
248Introduced in Perl 5.20.0
249
250Accepted in Perl 5.24.0
251
42e73e1c 252=back
253
254=head2 Removed features
255
256These features are no longer considered experimental and their functionality
257has disappeared. It's your own fault if you wrote production programs using
258these features after we explicitly told you not to (see L<perlpolicy>).
259
260=over 8
261
51c34fa4 262=item 5.005-style threading
42e73e1c 263
51c34fa4 264Introduced in Perl 5.005
42e73e1c 265
51c34fa4 266Removed in Perl 5.10
42e73e1c 267
51c34fa4 268=item perlcc
fe8d2675 269
51c34fa4 270Introduced in Perl 5.005
fe8d2675 271
51c34fa4 272Moved from Perl 5.9.0 to CPAN
fe8d2675 273
51c34fa4 274=item The pseudo-hash data type
fe8d2675 275
51c34fa4 276Introduced in Perl 5.6.0
fe8d2675 277
51c34fa4 278Removed in Perl 5.9.0
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279
280=item GetOpt::Long Options can now take multiple values at once (experimental)
281
282C<Getopt::Long> upgraded to version 2.35
283
284Removed in Perl 5.8.8
285
51c34fa4 286=item Assertions
fe8d2675 287
51c34fa4 288The C<-A> command line switch
fe8d2675 289
51c34fa4 290Introduced in Perl 5.9.0
fe8d2675 291
51c34fa4 292Removed in Perl 5.9.5
fe8d2675 293
51c34fa4 294=item Test::Harness::Straps
fe8d2675 295
51c34fa4 296Moved from Perl 5.10.1 to CPAN
fe8d2675 297
51c34fa4 298=item C<legacy>
fe8d2675 299
51c34fa4 300The experimental C<legacy> pragma was swallowed by the C<feature> pragma.
fe8d2675 301
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302Introduced in: 5.11.2
303
304Removed in: 5.11.3
fe8d2675 305
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306=item Lexical C<$_>
307
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308Using this feature triggered warnings in the category
309C<experimental::lexical_topic>.
310
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311Introduced in Perl 5.10.0
312
313Removed in Perl 5.24.0
314
315=item Array and hash container functions accept references
316
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317Using this feature triggered warnings in the category
318C<experimental::autoderef>.
319
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320Superseded by L</Postfix dereference syntax>.
321
322Introduced in Perl 5.14.0
323
324Removed in Perl 5.24.0
325
42e73e1c 326=back
327
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328=head1 SEE ALSO
329
330For a complete list of features check L<feature>.
331
42e73e1c 332=head1 AUTHORS
333
334brian d foy C<< <brian.d.foy@gmail.com> >>
335
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336SE<eacute>bastien Aperghis-Tramoni C<< <saper@cpan.org> >>
337
42e73e1c 338=head1 COPYRIGHT
339
340Copyright 2010, brian d foy C<< <brian.d.foy@gmail.com> >>
341
342=head1 LICENSE
343
344You can use and redistribute this document under the same terms as Perl
345itself.
346
347=cut