3 perlexperiment - A listing of experimental features in Perl
7 This document lists the current and past experimental features in the perl
8 core. Although all of these are documented with their appropriate topics,
9 this succinct listing gives you an overview and basic facts about their
12 So far we've merely tried to find and list the experimental features and infer
13 their inception, versions, etc. There's a lot of speculation here.
15 =head2 Current experiments
19 =item C<our> can now have an experimental optional attribute C<unique>
21 Introduced in Perl 5.8.0
23 Deprecated in Perl 5.10.0
25 The ticket for this feature is
26 L<[perl #119313]|https://rt.perl.org/rt3/Ticket/Display.html?id=119313>.
28 =item Smart match (C<~~>)
30 Introduced in Perl 5.10.0
32 Modified in Perl 5.10.1, 5.12.0
34 Using this feature triggers warnings in the category
35 C<experimental::smartmatch>.
37 The ticket for this feature is
38 L<[perl #119317]|https://rt.perl.org/rt3/Ticket/Display.html?id=119317>.
42 Introduced in Perl 5.10.0
44 Using this feature triggers warnings in the category
45 C<experimental::lexical_topic>.
47 The ticket for this feature is
48 L<[perl #119315]|https://rt.perl.org/rt3/Ticket/Display.html?id=119315>.
50 =item Pluggable keywords
52 See L<perlapi/PL_keyword_plugin> for the mechanism.
54 Introduced in: Perl 5.11.2
56 =item Array and hash container functions accept references
58 Introduced in Perl 5.14.0
60 =item Lexical subroutines
62 Introduced in: Perl 5.18
64 See also: L<perlsub/Lexical Subroutines>
66 Using this feature triggers warnings in the category
67 C<experimental::lexical_subs>.
69 =item Regular Expression Set Operations
71 Introduced in: Perl 5.18
73 See also: L<perlrecharclass/Extended Bracketed Character Classes>
75 Using this feature triggers warnings in the category
76 C<experimental::regex_sets>.
78 =item C<\s> in regexp matches vertical tab
80 Introduced in Perl 5.18
82 =item The <:win32> IO pseudolayer
86 =item There is an C<installhtml> target in the Makefile.
88 The ticket for this feature is
89 L<[perl #116487]|https://rt.perl.org/rt3/Ticket/Display.html?id=116487>.
91 =item Unicode in Perl on EBCDIC
93 See also: L<perlre/"Special Backtracking Control Verbs">
97 =head2 Accepted features
99 These features were so wildly successful and played so well with others that
100 we decided to remove their experimental status and admit them as full, stable
101 features in the world of Perl, lavishing all the benefits and luxuries thereof.
102 They are also awarded +5 Stability and +3 Charisma.
108 Introduced in Perl 5.005
110 =item die accepts a reference
112 Introduced in Perl 5.005
116 Introduced in Perl 5.6.0
118 See also L<perldebug>, L<perldebtut>
120 =item Weak references
122 Introduced in Perl 5.6.0
124 =item Internal file glob
126 Introduced in Perl 5.6.0
128 =item fork() emulation
130 Introduced in Perl 5.6.1
134 =item -Dusemultiplicity -Duseithreads
136 Introduced in Perl 5.6.0
138 Accepted in Perl 5.8.0
140 =item Support for long doubles
142 Introduced in Perl 5.6.0
144 Accepted in Perl 5.8.1
146 =item The C<\N> regex character class
148 The C<\N> character class, not to be confused with the named character
149 sequence C<\N{NAME}>, denotes any non-newline character in a regular
152 Introduced in Perl 5.12
154 Exact version of acceptance unclear, but no later than Perl 5.18.
156 =item C<(?{code})> and C<(??{ code })>
158 Introduced in Perl 5.6.0
160 Accepted in Perl 5.20.0
164 =item Linux abstract Unix domain sockets
166 Introduced in Perl 5.9.2
168 Accepted before Perl 5.20.0. The Socket library is now primarily maintained
169 on CPAN, rather than in the perl core.
173 =item Lvalue subroutines
175 Introduced in Perl 5.6.0
177 Accepted in Perl 5.20.0
181 =item Backtracking control verbs
185 Introduced in: Perl 5.10
187 Accepted in Perl 5.20.0
189 =item The <:pop> IO pseudolayer
193 Accepted in Perl 5.20.0
197 =head2 Removed features
199 These features are no longer considered experimental and their functionality
200 has disappeared. It's your own fault if you wrote production programs using
201 these features after we explicitly told you not to (see L<perlpolicy>).
205 =item 5.005-style threading
207 Introduced in Perl 5.005
213 Introduced in Perl 5.005
215 Moved from Perl 5.9.0 to CPAN
217 =item The pseudo-hash data type
219 Introduced in Perl 5.6.0
221 Removed in Perl 5.9.0
223 =item GetOpt::Long Options can now take multiple values at once (experimental)
225 C<Getopt::Long> upgraded to version 2.35
227 Removed in Perl 5.8.8
231 The C<-A> command line switch
233 Introduced in Perl 5.9.0
235 Removed in Perl 5.9.5
237 =item Test::Harness::Straps
239 Moved from Perl 5.10.1 to CPAN
243 The experimental C<legacy> pragma was swallowed by the C<feature> pragma.
245 Introduced in: 5.11.2
253 brian d foy C<< <brian.d.foy@gmail.com> >>
255 SE<eacute>bastien Aperghis-Tramoni C<< <saper@cpan.org> >>
259 Copyright 2010, brian d foy C<< <brian.d.foy@gmail.com> >>
263 You can use and redistribute this document under the same terms as Perl