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