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 Lvalue subroutines
21 Introduced in Perl 5.6.0
25 =item C<our> can now have an experimental optional attribute C<unique>
27 Introduced in Perl 5.8.0
29 Deprecated in Perl 5.10.0
31 =item Linux abstract Unix domain sockets
33 Introduced in Perl 5.9.2
37 =item Smart match (C<~~>)
39 Introduced in Perl 5.10.0
41 Modified in Perl 5.10.1, 5.12.0
43 Using this feature triggers warnings in the category
44 C<experimental::smartmatch>.
48 Introduced in Perl 5.10.0
50 Using this feature triggers warnings in the category
51 C<experimental::lexical_topic>.
53 =item Pluggable keywords
55 See L<perlapi/PL_keyword_plugin> for the mechanism.
57 Introduced in: Perl 5.11.2
59 =item Array and hash container functions accept references
61 Introduced in Perl 5.14.0
63 =item Lexical subroutines
65 Introduced in: Perl 5.18
67 See also: L<perlsub/Lexical Subroutines>
69 Using this feature triggers warnings in the category
70 C<experimental::lexical_subs>.
72 =item Regular Expression Set Operations
74 Introduced in: Perl 5.18
76 See also: L<perlrecharclass/Extended Bracketed Character Classes>
78 Using this feature triggers warnings in the category
79 C<experimental::regex_sets>.
81 =item C<\s> in regexp matches vertical tab
83 Introduced in Perl 5.18
85 =item The <:pop> IO pseudolayer
89 =item The <:win32> IO pseudolayer
97 =item internal functions with M flag
103 Introduced in Perl 5.13.7
105 =item internal API for C<%^H>
107 Introduced in Perl 5.13.7
109 See also C<cophh_> in L<perlapi>.
113 Introduced in Perl 5.18.0
115 =item av_create_and_push
117 =item av_create_and_unshift_one
119 =item av_create_and_unshift_one
121 =item cop_store_label
123 Introduced in Perl 5.16.0
125 =item PL_keyword_plugin
127 =item gv_fetchmethod_*_flags
129 Introduced in Perl 5.16.0
131 =item hv_iternext_flags
137 =item lex_grow_linestr
141 =item lex_peek_unichar
147 =item lex_read_unichar
167 =item PL_parser-E<gt>bufend
169 =item PL_parser-E<gt>bufptr
171 =item PL_parser-E<gt>linestart
173 =item PL_parser-E<gt>linestr
181 =item sv_utf8_downgrade
183 =item bytes_from_utf8
189 =item There is an C<installhtml> target in the Makefile.
191 =item Unicode in Perl on EBCDIC
193 See also: L<perlre/"Special Backtracking Control Verbs">
195 =item Code expressions, conditional expressions, and independent expressions in regexes
197 =item gv_try_downgrade
199 See also L<perlintern>
201 =item Experimental Support for Sun Studio Compilers for Linux OS
203 See also L<perllinux>
207 =head2 Accepted features
209 These features were so wildly successful and played so well with others that
210 we decided to remove their experimental status and admit them as full, stable
211 features in the world of Perl, lavishing all the benefits and luxuries thereof.
212 They are also awarded +5 Stability and +3 Charisma.
218 Introduced in Perl 5.005
220 =item die accepts a reference
222 Introduced in Perl 5.005
226 Introduced in Perl 5.6.0
228 See also L<perldebug>, L<perldebtut>
230 =item Weak references
232 Introduced in Perl 5.6.0
234 =item Internal file glob
236 Introduced in Perl 5.6.0
238 =item fork() emulation
240 Introduced in Perl 5.6.1
244 =item -Dusemultiplicity -Duseithreads
246 Introduced in Perl 5.6.0
248 Accepted in Perl 5.8.0
250 =item Support for long doubles
252 Introduced in Perl 5.6.0
254 Accepted in Perl 5.8.1
256 =item The C<\N> regex character class
258 The C<\N> character class, not to be confused with the named character
259 sequence C<\N{NAME}>, denotes any non-newline character in a regular
262 Introduced in Perl 5.12
264 Exact version of acceptance unclear, but no later than Perl 5.18.
266 =item C<(?{code})> and C<(??{ code })>
268 Introduced in Perl 5.6.0
270 Accepted in Perl 5.20.0
274 =item Backtracking control verbs
278 Introduced in: Perl 5.10
280 Accepted in Perl 5.20.0
284 =head2 Removed features
286 These features are no longer considered experimental and their functionality
287 has disappeared. It's your own fault if you wrote production programs using
288 these features after we explicitly told you not to (see L<perlpolicy>).
292 =item 5.005-style threading
294 Introduced in Perl 5.005
300 Introduced in Perl 5.005
302 Moved from Perl 5.9.0 to CPAN
304 =item The pseudo-hash data type
306 Introduced in Perl 5.6.0
308 Removed in Perl 5.9.0
310 =item GetOpt::Long Options can now take multiple values at once (experimental)
312 C<Getopt::Long> upgraded to version 2.35
314 Removed in Perl 5.8.8
318 The C<-A> command line switch
320 Introduced in Perl 5.9.0
322 Removed in Perl 5.9.5
324 =item Test::Harness::Straps
326 Moved from Perl 5.10.1 to CPAN
330 The experimental C<legacy> pragma was swallowed by the C<feature> pragma.
332 Introduced in: 5.11.2
340 brian d foy C<< <brian.d.foy@gmail.com> >>
342 SE<eacute>bastien Aperghis-Tramoni C<< <saper@cpan.org> >>
346 Copyright 2010, brian d foy C<< <brian.d.foy@gmail.com> >>
350 You can use and redistribute this document under the same terms as Perl