1PERLEXPERIMENT(1)      Perl Programmers Reference Guide      PERLEXPERIMENT(1)
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NAME

6       perlexperiment - A listing of experimental features in Perl
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DESCRIPTION

9       This document lists the current and past experimental features in the
10       perl core. Although all of these are documented with their appropriate
11       topics, this succinct listing gives you an overview and basic facts
12       about their status.
13
14       So far we've merely tried to find and list the experimental features
15       and infer their inception, versions, etc. There's a lot of speculation
16       here.
17
18   Current experiments
19       Smart match ("~~")
20               Introduced in Perl 5.10.0
21
22               Modified in Perl 5.10.1, 5.12.0
23
24               Using this feature triggers warnings in the category
25               "experimental::smartmatch".
26
27               The ticket for this feature is [perl #13173]
28               <https://github.com/Perl/perl5/issues/13173>.
29
30       Pluggable keywords
31               The ticket for this feature is [perl #13199]
32               <https://github.com/Perl/perl5/issues/13199>.
33
34               See "PL_keyword_plugin" in perlapi for the mechanism.
35
36               Introduced in Perl 5.11.2
37
38       Regular Expression Set Operations
39               Introduced in Perl 5.18
40
41               The ticket for this feature is [perl #13197]
42               <https://github.com/Perl/perl5/issues/13197>.
43
44               See also: "Extended Bracketed Character Classes" in
45               perlrecharclass
46
47               Using this feature triggers warnings in the category
48               "experimental::regex_sets".
49
50       Subroutine signatures
51               Introduced in Perl 5.20.0
52
53               Using this feature triggers warnings in the category
54               "experimental::signatures".
55
56               The ticket for this feature is [perl #13681]
57               <https://github.com/Perl/perl5/issues/13681>.
58
59       Aliasing via reference
60               Introduced in Perl 5.22.0
61
62               Using this feature triggers warnings in the category
63               "experimental::refaliasing".
64
65               The ticket for this feature is [perl #14150]
66               <https://github.com/Perl/perl5/issues/14150>.
67
68               See also: "Assigning to References" in perlref
69
70       The "const" attribute
71               Introduced in Perl 5.22.0
72
73               Using this feature triggers warnings in the category
74               "experimental::const_attr".
75
76               The ticket for this feature is [perl #14428]
77               <https://github.com/Perl/perl5/issues/14428>.
78
79               See also: "Constant Functions" in perlsub
80
81       use re 'strict';
82               Introduced in Perl 5.22.0
83
84               Using this feature triggers warnings in the category
85               "experimental::re_strict".
86
87               See "'strict' mode" in re
88
89       The <:win32> IO pseudolayer
90               The ticket for this feature is [perl #13198]
91               <https://github.com/Perl/perl5/issues/13198>.
92
93               See also "PERLIO" in perlrun
94
95       Declaring a reference to a variable
96               Introduced in Perl 5.26.0
97
98               Using this feature triggers warnings in the category
99               "experimental::declared_refs".
100
101               The ticket for this feature is [perl #15458]
102               <https://github.com/Perl/perl5/issues/15458>.
103
104               See also: "Declaring a Reference to a Variable" in perlref
105
106       There is an "installhtml" target in the Makefile.
107               The ticket for this feature is [perl #12726]
108               <https://github.com/Perl/perl5/issues/12726>.
109
110       (Limited) Variable-length look-behind
111               Introduced in Perl 5.30.0.  Variability of up to 255 characters
112               is handled.
113
114               Using this feature triggers warnings in the category
115               "experimental::vlb".
116
117               See also: "(*positive_lookbehind:pattern)" in perlre and
118               "(*negative_lookbehind:pattern)" in perlre
119
120   Accepted features
121       These features were so wildly successful and played so well with others
122       that we decided to remove their experimental status and admit them as
123       full, stable features in the world of Perl, lavishing all the benefits
124       and luxuries thereof.  They are also awarded +5 Stability and +3
125       Charisma.
126
127       64-bit support
128               Introduced in Perl 5.005
129
130       die accepts a reference
131               Introduced in Perl 5.005
132
133       DB module
134               Introduced in Perl 5.6.0
135
136               See also perldebug, perldebtut
137
138       Weak references
139               Introduced in Perl 5.6.0
140
141       Internal file glob
142               Introduced in Perl 5.6.0
143
144       fork() emulation
145               Introduced in Perl 5.6.1
146
147               See also perlfork
148
149       -Dusemultiplicity -Duseithreads
150               Introduced in Perl 5.6.0
151
152               Accepted in Perl 5.8.0
153
154       Support for long doubles
155               Introduced in Perl 5.6.0
156
157               Accepted in Perl 5.8.1
158
159       The "\N" regex character class
160               The "\N" character class, not to be confused with the named
161               character sequence "\N{NAME}", denotes any non-newline
162               character in a regular expression.
163
164               Introduced in Perl 5.12
165
166               Exact version of acceptance unclear, but no later than Perl
167               5.18.
168
169       "(?{code})" and "(??{ code })"
170               Introduced in Perl 5.6.0
171
172               Accepted in Perl 5.20.0
173
174               See also perlre
175
176       Linux abstract Unix domain sockets
177               Introduced in Perl 5.9.2
178
179               Accepted before Perl 5.20.0.  The Socket library is now
180               primarily maintained on CPAN, rather than in the perl core.
181
182               See also Socket
183
184       Lvalue subroutines
185               Introduced in Perl 5.6.0
186
187               Accepted in Perl 5.20.0
188
189               See also perlsub
190
191       Backtracking control verbs
192               "(*ACCEPT)"
193
194               Introduced in Perl 5.10
195
196               Accepted in Perl 5.20.0
197
198       The <:pop> IO pseudolayer
199               See also "PERLIO" in perlrun
200
201               Accepted in Perl 5.20.0
202
203       "\s" in regexp matches vertical tab
204               Accepted in Perl 5.22.0
205
206       Postfix dereference syntax
207               Introduced in Perl 5.20.0
208
209               Accepted in Perl 5.24.0
210
211       Lexical subroutines
212               Introduced in Perl 5.18.0
213
214               Accepted in Perl 5.26.0
215
216       String- and number-specific bitwise operators
217               Introduced in Perl 5.22.0
218
219               Accepted in Perl 5.28.0
220
221       Alphabetic assertions
222               Introduced in Perl 5.28.0
223
224               Accepted in Perl 5.32.0
225
226       Script runs
227               Introduced in Perl 5.28.0
228
229               Accepted in Perl 5.32.0
230
231   Removed features
232       These features are no longer considered experimental and their
233       functionality has disappeared. It's your own fault if you wrote
234       production programs using these features after we explicitly told you
235       not to (see perlpolicy).
236
237       5.005-style threading
238               Introduced in Perl 5.005
239
240               Removed in Perl 5.10
241
242       perlcc  Introduced in Perl 5.005
243
244               Moved from Perl 5.9.0 to CPAN
245
246       The pseudo-hash data type
247               Introduced in Perl 5.6.0
248
249               Removed in Perl 5.9.0
250
251       GetOpt::Long Options can now take multiple values at once
252       (experimental)
253               "Getopt::Long" upgraded to version 2.35
254
255               Removed in Perl 5.8.8
256
257       Assertions
258               The "-A" command line switch
259
260               Introduced in Perl 5.9.0
261
262               Removed in Perl 5.9.5
263
264       Test::Harness::Straps
265               Moved from Perl 5.10.1 to CPAN
266
267       "legacy"
268               The experimental "legacy" pragma was swallowed by the "feature"
269               pragma.
270
271               Introduced in Perl 5.11.2
272
273               Removed in Perl 5.11.3
274
275       Lexical $_
276               Using this feature triggered warnings in the category
277               "experimental::lexical_topic".
278
279               Introduced in Perl 5.10.0
280
281               Removed in Perl 5.24.0
282
283       Array and hash container functions accept references
284               Using this feature triggered warnings in the category
285               "experimental::autoderef".
286
287               Superseded by "Postfix dereference syntax".
288
289               Introduced in Perl 5.14.0
290
291               Removed in Perl 5.24.0
292
293       "our" can have an experimental optional attribute "unique"
294               Introduced in Perl 5.8.0
295
296               Deprecated in Perl 5.10.0
297
298               Removed in Perl 5.28.0
299

SEE ALSO

301       For a complete list of features check feature.
302

AUTHORS

304       brian d foy "<brian.d.foy@gmail.com>"
305
306       Sebastien Aperghis-Tramoni "<saper@cpan.org>"
307

309       Copyright 2010, brian d foy "<brian.d.foy@gmail.com>"
310

LICENSE

312       You can use and redistribute this document under the same terms as Perl
313       itself.
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317perl v5.32.1                      2021-03-31                 PERLEXPERIMENT(1)
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