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69bcf1d3 FC |
1 | # -*- buffer-read-only: t -*- |
2 | # !!!!!!! DO NOT EDIT THIS FILE !!!!!!! | |
3 | # This file is built by regen/feature.pl. | |
4 | # Any changes made here will be lost! | |
5 | ||
0d863452 RH |
6 | package feature; |
7 | ||
c22e17d0 | 8 | our $VERSION = '1.54'; |
0d863452 | 9 | |
0bb01b05 | 10 | our %feature = ( |
2a4315f8 | 11 | fc => 'feature_fc', |
47e9d84a EB |
12 | say => 'feature_say', |
13 | state => 'feature_state', | |
1863b879 | 14 | switch => 'feature_switch', |
cec892e7 | 15 | bitwise => 'feature_bitwise', |
7d789282 | 16 | evalbytes => 'feature_evalbytes', |
30d9c59b | 17 | signatures => 'feature_signatures', |
84ed0108 | 18 | current_sub => 'feature___SUB__', |
baabe3fb | 19 | refaliasing => 'feature_refaliasing', |
158becca | 20 | postderef_qq => 'feature_postderef_qq', |
cda6b701 | 21 | unicode_eval => 'feature_unieval', |
82d83da3 | 22 | declared_refs => 'feature_myref', |
47e9d84a | 23 | unicode_strings => 'feature_unicode', |
bc9b29db RH |
24 | ); |
25 | ||
0d2bd2aa | 26 | our %feature_bundle = ( |
c22e17d0 DIM |
27 | "5.10" => [qw(say state switch)], |
28 | "5.11" => [qw(say state switch unicode_strings)], | |
2a4315f8 | 29 | "5.15" => [qw(current_sub evalbytes fc say state switch unicode_eval unicode_strings)], |
1c2511e0 | 30 | "5.23" => [qw(current_sub evalbytes fc postderef_qq say state switch unicode_eval unicode_strings)], |
401d2aaa | 31 | "5.27" => [qw(bitwise current_sub evalbytes fc postderef_qq say state switch unicode_eval unicode_strings)], |
c22e17d0 DIM |
32 | "all" => [qw(bitwise current_sub declared_refs evalbytes fc postderef_qq refaliasing say signatures state switch unicode_eval unicode_strings)], |
33 | "default" => [qw()], | |
0d863452 | 34 | ); |
d052521a | 35 | |
88da30d7 FC |
36 | $feature_bundle{"5.12"} = $feature_bundle{"5.11"}; |
37 | $feature_bundle{"5.13"} = $feature_bundle{"5.11"}; | |
38 | $feature_bundle{"5.14"} = $feature_bundle{"5.11"}; | |
39 | $feature_bundle{"5.16"} = $feature_bundle{"5.15"}; | |
d6402ebe | 40 | $feature_bundle{"5.17"} = $feature_bundle{"5.15"}; |
52fc5c56 | 41 | $feature_bundle{"5.18"} = $feature_bundle{"5.15"}; |
d09258e7 RS |
42 | $feature_bundle{"5.19"} = $feature_bundle{"5.15"}; |
43 | $feature_bundle{"5.20"} = $feature_bundle{"5.15"}; | |
b530a4ea RS |
44 | $feature_bundle{"5.21"} = $feature_bundle{"5.15"}; |
45 | $feature_bundle{"5.22"} = $feature_bundle{"5.15"}; | |
2ad792cd | 46 | $feature_bundle{"5.24"} = $feature_bundle{"5.23"}; |
2c5484a6 RS |
47 | $feature_bundle{"5.25"} = $feature_bundle{"5.23"}; |
48 | $feature_bundle{"5.26"} = $feature_bundle{"5.23"}; | |
401d2aaa | 49 | $feature_bundle{"5.28"} = $feature_bundle{"5.27"}; |
d361a1e6 S |
50 | $feature_bundle{"5.29"} = $feature_bundle{"5.27"}; |
51 | $feature_bundle{"5.30"} = $feature_bundle{"5.27"}; | |
88da30d7 | 52 | $feature_bundle{"5.9.5"} = $feature_bundle{"5.10"}; |
db629560 FC |
53 | my %noops = ( |
54 | postderef => 1, | |
55 | lexical_subs => 1, | |
56 | ); | |
c22e17d0 DIM |
57 | my %removed = ( |
58 | array_base => 1, | |
59 | ); | |
69bcf1d3 | 60 | |
0bb01b05 FC |
61 | our $hint_shift = 26; |
62 | our $hint_mask = 0x1c000000; | |
401d2aaa | 63 | our @hint_bundles = qw( default 5.10 5.11 5.15 5.23 5.27 ); |
ada44f8c | 64 | |
69bcf1d3 FC |
65 | # This gets set (for now) in $^H as well as in %^H, |
66 | # for runtime speed of the uc/lc/ucfirst/lcfirst functions. | |
67 | # See HINT_UNI_8_BIT in perl.h. | |
68 | our $hint_uni8bit = 0x00000800; | |
7dfde25d | 69 | |
0d863452 | 70 | # TODO: |
1c321dc6 | 71 | # - think about versioned features (use feature switch => 2) |
0d863452 RH |
72 | |
73 | =head1 NAME | |
74 | ||
e1b711da | 75 | feature - Perl pragma to enable new features |
0d863452 RH |
76 | |
77 | =head1 SYNOPSIS | |
78 | ||
47e9d84a | 79 | use feature qw(say switch); |
0d863452 | 80 | given ($foo) { |
0b25e784 DG |
81 | when (1) { say "\$foo == 1" } |
82 | when ([2,3]) { say "\$foo == 2 || \$foo == 3" } | |
83 | when (/^a[bc]d$/) { say "\$foo eq 'abd' || \$foo eq 'acd'" } | |
84 | when ($_ > 100) { say "\$foo > 100" } | |
85 | default { say "None of the above" } | |
0d863452 RH |
86 | } |
87 | ||
ec488c7f RGS |
88 | use feature ':5.10'; # loads all features available in perl 5.10 |
89 | ||
0b25e784 DG |
90 | use v5.10; # implicitly loads :5.10 feature bundle |
91 | ||
0d863452 RH |
92 | =head1 DESCRIPTION |
93 | ||
94 | It is usually impossible to add new syntax to Perl without breaking | |
b22bbcf0 | 95 | some existing programs. This pragma provides a way to minimize that |
1863b879 RGS |
96 | risk. New syntactic constructs, or new semantic meanings to older |
97 | constructs, can be enabled by C<use feature 'foo'>, and will be parsed | |
b22bbcf0 | 98 | only when the appropriate feature pragma is in scope. (Nevertheless, the |
4a904372 FC |
99 | C<CORE::> prefix provides access to all Perl keywords, regardless of this |
100 | pragma.) | |
0d863452 | 101 | |
9eb27be9 RGS |
102 | =head2 Lexical effect |
103 | ||
104 | Like other pragmas (C<use strict>, for example), features have a lexical | |
301381dc | 105 | effect. C<use feature qw(foo)> will only make the feature "foo" available |
9eb27be9 RGS |
106 | from that point to the end of the enclosing block. |
107 | ||
108 | { | |
109 | use feature 'say'; | |
110 | say "say is available here"; | |
111 | } | |
112 | print "But not here.\n"; | |
113 | ||
5e36ed56 RGS |
114 | =head2 C<no feature> |
115 | ||
b22bbcf0 | 116 | Features can also be turned off by using C<no feature "foo">. This too |
5e36ed56 RGS |
117 | has lexical effect. |
118 | ||
119 | use feature 'say'; | |
120 | say "say is available here"; | |
121 | { | |
122 | no feature 'say'; | |
123 | print "But not here.\n"; | |
124 | } | |
125 | say "Yet it is here."; | |
126 | ||
39ec54a5 RS |
127 | C<no feature> with no features specified will reset to the default group. To |
128 | disable I<all> features (an unusual request!) use C<no feature ':all'>. | |
5e36ed56 | 129 | |
0b25e784 DG |
130 | =head1 AVAILABLE FEATURES |
131 | ||
0d863452 RH |
132 | =head2 The 'say' feature |
133 | ||
0b25e784 | 134 | C<use feature 'say'> tells the compiler to enable the Perl 6 style |
9eb27be9 | 135 | C<say> function. |
0d863452 RH |
136 | |
137 | See L<perlfunc/say> for details. | |
138 | ||
0b25e784 DG |
139 | This feature is available starting with Perl 5.10. |
140 | ||
141 | =head2 The 'state' feature | |
712d05cf RGS |
142 | |
143 | C<use feature 'state'> tells the compiler to enable C<state> | |
9eb27be9 | 144 | variables. |
712d05cf | 145 | |
e60bcc8b RGS |
146 | See L<perlsub/"Persistent Private Variables"> for details. |
147 | ||
0b25e784 DG |
148 | This feature is available starting with Perl 5.10. |
149 | ||
47e9d84a EB |
150 | =head2 The 'switch' feature |
151 | ||
7caca87c DB |
152 | B<WARNING>: Because the L<smartmatch operator|perlop/"Smartmatch Operator"> is |
153 | experimental, Perl will warn when you use this feature, unless you have | |
154 | explicitly disabled the warning: | |
155 | ||
156 | no warnings "experimental::smartmatch"; | |
157 | ||
7896dde7 | 158 | C<use feature 'switch'> tells the compiler to enable the Perl 6 |
47e9d84a EB |
159 | given/when construct. |
160 | ||
48238296 | 161 | See L<perlsyn/"Switch Statements"> for details. |
47e9d84a | 162 | |
0b25e784 DG |
163 | This feature is available starting with Perl 5.10. |
164 | ||
165 | =head2 The 'unicode_strings' feature | |
1863b879 | 166 | |
850b7ec9 | 167 | C<use feature 'unicode_strings'> tells the compiler to use Unicode rules |
20db7501 KW |
168 | in all string operations executed within its scope (unless they are also |
169 | within the scope of either C<use locale> or C<use bytes>). The same applies | |
170 | to all regular expressions compiled within the scope, even if executed outside | |
2269d15c KW |
171 | it. It does not change the internal representation of strings, but only how |
172 | they are interpreted. | |
20db7501 KW |
173 | |
174 | C<no feature 'unicode_strings'> tells the compiler to use the traditional | |
850b7ec9 | 175 | Perl rules wherein the native character set rules is used unless it is |
20db7501 KW |
176 | clear to Perl that Unicode is desired. This can lead to some surprises |
177 | when the behavior suddenly changes. (See | |
178 | L<perlunicode/The "Unicode Bug"> for details.) For this reason, if you are | |
179 | potentially using Unicode in your program, the | |
180 | C<use feature 'unicode_strings'> subpragma is B<strongly> recommended. | |
181 | ||
2e2b2571 | 182 | This feature is available starting with Perl 5.12; was almost fully |
d6c970c7 | 183 | implemented in Perl 5.14; and extended in Perl 5.16 to cover C<quotemeta>; |
20ae58f7 AC |
184 | was extended further in Perl 5.26 to cover L<the range |
185 | operator|perlop/Range Operators>; and was extended again in Perl 5.28 to | |
186 | cover L<special-cased whitespace splitting|perlfunc/split>. | |
1863b879 | 187 | |
0b25e784 | 188 | =head2 The 'unicode_eval' and 'evalbytes' features |
7289c5e6 | 189 | |
9891e9b7 KW |
190 | Together, these two features are intended to replace the legacy string |
191 | C<eval> function, which behaves problematically in some instances. They are | |
192 | available starting with Perl 5.16, and are enabled by default by a | |
193 | S<C<use 5.16>> or higher declaration. | |
194 | ||
195 | C<unicode_eval> changes the behavior of plain string C<eval> to work more | |
196 | consistently, especially in the Unicode world. Certain (mis)behaviors | |
197 | couldn't be changed without breaking some things that had come to rely on | |
198 | them, so the feature can be enabled and disabled. Details are at | |
199 | L<perlfunc/Under the "unicode_eval" feature>. | |
200 | ||
201 | C<evalbytes> is like string C<eval>, but operating on a byte stream that is | |
202 | not UTF-8 encoded. Details are at L<perlfunc/evalbytes EXPR>. Without a | |
203 | S<C<use feature 'evalbytes'>> nor a S<C<use v5.16>> (or higher) declaration in | |
204 | the current scope, you can still access it by instead writing | |
205 | C<CORE::evalbytes>. | |
7289c5e6 | 206 | |
84ed0108 FC |
207 | =head2 The 'current_sub' feature |
208 | ||
209 | This provides the C<__SUB__> token that returns a reference to the current | |
210 | subroutine or C<undef> outside of a subroutine. | |
211 | ||
212 | This feature is available starting with Perl 5.16. | |
213 | ||
01868d00 FC |
214 | =head2 The 'array_base' feature |
215 | ||
c22e17d0 DIM |
216 | This feature supported the legacy C<$[> variable. See L<perlvar/$[>. |
217 | It was on by default but disabled under C<use v5.16> (see | |
218 | L</IMPLICIT LOADING>, below) and unavailable since perl 5.30. | |
01868d00 FC |
219 | |
220 | This feature is available under this name starting with Perl 5.16. In | |
221 | previous versions, it was simply on all the time, and this pragma knew | |
222 | nothing about it. | |
223 | ||
2a4315f8 BF |
224 | =head2 The 'fc' feature |
225 | ||
226 | C<use feature 'fc'> tells the compiler to enable the C<fc> function, | |
227 | which implements Unicode casefolding. | |
228 | ||
229 | See L<perlfunc/fc> for details. | |
230 | ||
231 | This feature is available from Perl 5.16 onwards. | |
232 | ||
ca40957e FC |
233 | =head2 The 'lexical_subs' feature |
234 | ||
8f7d85af FC |
235 | In Perl versions prior to 5.26, this feature enabled |
236 | declaration of subroutines via C<my sub foo>, C<state sub foo> | |
237 | and C<our sub foo> syntax. See L<perlsub/Lexical Subroutines> for details. | |
ca40957e | 238 | |
8f7d85af FC |
239 | This feature is available from Perl 5.18 onwards. From Perl 5.18 to 5.24, |
240 | it was classed as experimental, and Perl emitted a warning for its | |
241 | usage, except when explicitly disabled: | |
ca40957e | 242 | |
8f7d85af | 243 | no warnings "experimental::lexical_subs"; |
ca40957e | 244 | |
8f7d85af FC |
245 | As of Perl 5.26, use of this feature no longer triggers a warning, though |
246 | the C<experimental::lexical_subs> warning category still exists (for | |
247 | compatibility with code that disables it). In addition, this syntax is | |
248 | not only no longer experimental, but it is enabled for all Perl code, | |
249 | regardless of what feature declarations are in scope. | |
ca40957e | 250 | |
f86d720e RS |
251 | =head2 The 'postderef' and 'postderef_qq' features |
252 | ||
1c2511e0 AC |
253 | The 'postderef_qq' feature extends the applicability of L<postfix |
254 | dereference syntax|perlref/Postfix Dereference Syntax> so that postfix array | |
255 | and scalar dereference are available in double-quotish interpolations. For | |
256 | example, it makes the following two statements equivalent: | |
f86d720e | 257 | |
1c2511e0 AC |
258 | my $s = "[@{ $h->{a} }]"; |
259 | my $s = "[$h->{a}->@*]"; | |
f86d720e | 260 | |
1c2511e0 AC |
261 | This feature is available from Perl 5.20 onwards. In Perl 5.20 and 5.22, it |
262 | was classed as experimental, and Perl emitted a warning for its | |
2ad792cd AC |
263 | usage, except when explicitly disabled: |
264 | ||
265 | no warnings "experimental::postderef"; | |
266 | ||
1c2511e0 | 267 | As of Perl 5.24, use of this feature no longer triggers a warning, though |
2ad792cd AC |
268 | the C<experimental::postderef> warning category still exists (for |
269 | compatibility with code that disables it). | |
f86d720e | 270 | |
1c2511e0 AC |
271 | The 'postderef' feature was used in Perl 5.20 and Perl 5.22 to enable |
272 | postfix dereference syntax outside double-quotish interpolations. In those | |
273 | versions, using it triggered the C<experimental::postderef> warning in the | |
274 | same way as the 'postderef_qq' feature did. As of Perl 5.24, this syntax is | |
275 | not only no longer experimental, but it is enabled for all Perl code, | |
276 | regardless of what feature declarations are in scope. | |
277 | ||
30d9c59b Z |
278 | =head2 The 'signatures' feature |
279 | ||
280 | B<WARNING>: This feature is still experimental and the implementation may | |
281 | change in future versions of Perl. For this reason, Perl will | |
282 | warn when you use the feature, unless you have explicitly disabled the | |
283 | warning: | |
284 | ||
285 | no warnings "experimental::signatures"; | |
286 | ||
287 | This enables unpacking of subroutine arguments into lexical variables | |
288 | by syntax such as | |
289 | ||
290 | sub foo ($left, $right) { | |
291 | return $left + $right; | |
292 | } | |
293 | ||
294 | See L<perlsub/Signatures> for details. | |
295 | ||
296 | This feature is available from Perl 5.20 onwards. | |
297 | ||
baabe3fb | 298 | =head2 The 'refaliasing' feature |
82848c10 FC |
299 | |
300 | B<WARNING>: This feature is still experimental and the implementation may | |
301 | change in future versions of Perl. For this reason, Perl will | |
302 | warn when you use the feature, unless you have explicitly disabled the | |
303 | warning: | |
304 | ||
baabe3fb | 305 | no warnings "experimental::refaliasing"; |
82848c10 FC |
306 | |
307 | This enables aliasing via assignment to references: | |
308 | ||
309 | \$a = \$b; # $a and $b now point to the same scalar | |
310 | \@a = \@b; # to the same array | |
311 | \%a = \%b; | |
312 | \&a = \&b; | |
313 | foreach \%hash (@array_of_hash_refs) { | |
314 | ... | |
315 | } | |
316 | ||
317 | See L<perlref/Assigning to References> for details. | |
318 | ||
319 | This feature is available from Perl 5.22 onwards. | |
320 | ||
70ea8edf FC |
321 | =head2 The 'bitwise' feature |
322 | ||
70ea8edf FC |
323 | This makes the four standard bitwise operators (C<& | ^ ~>) treat their |
324 | operands consistently as numbers, and introduces four new dotted operators | |
325 | (C<&. |. ^. ~.>) that treat their operands consistently as strings. The | |
326 | same applies to the assignment variants (C<&= |= ^= &.= |.= ^.=>). | |
327 | ||
328 | See L<perlop/Bitwise String Operators> for details. | |
329 | ||
193789ac FC |
330 | This feature is available from Perl 5.22 onwards. Starting in Perl 5.28, |
331 | C<use v5.28> will enable the feature. Before 5.28, it was still | |
332 | experimental and would emit a warning in the "experimental::bitwise" | |
333 | category. | |
70ea8edf | 334 | |
5c703779 FC |
335 | =head2 The 'declared_refs' feature |
336 | ||
337 | B<WARNING>: This feature is still experimental and the implementation may | |
338 | change in future versions of Perl. For this reason, Perl will | |
339 | warn when you use the feature, unless you have explicitly disabled the | |
340 | warning: | |
341 | ||
342 | no warnings "experimental::declared_refs"; | |
343 | ||
344 | This allows a reference to a variable to be declared with C<my>, C<state>, | |
345 | our C<our>, or localized with C<local>. It is intended mainly for use in | |
346 | conjunction with the "refaliasing" feature. See L<perlref/Declaring a | |
347 | Reference to a Variable> for examples. | |
348 | ||
349 | This feature is available from Perl 5.26 onwards. | |
350 | ||
bc9b29db RH |
351 | =head1 FEATURE BUNDLES |
352 | ||
0b25e784 | 353 | It's possible to load multiple features together, using |
b22bbcf0 | 354 | a I<feature bundle>. The name of a feature bundle is prefixed with |
0b25e784 DG |
355 | a colon, to distinguish it from an actual feature. |
356 | ||
357 | use feature ":5.10"; | |
358 | ||
359 | The following feature bundles are available: | |
360 | ||
361 | bundle features included | |
362 | --------- ----------------- | |
c22e17d0 | 363 | :default |
0b25e784 | 364 | |
c22e17d0 | 365 | :5.10 say state switch |
0b25e784 | 366 | |
c22e17d0 | 367 | :5.12 say state switch unicode_strings |
0b25e784 | 368 | |
c22e17d0 | 369 | :5.14 say state switch unicode_strings |
0b25e784 DG |
370 | |
371 | :5.16 say state switch unicode_strings | |
2a4315f8 | 372 | unicode_eval evalbytes current_sub fc |
0b25e784 | 373 | |
52fc5c56 FC |
374 | :5.18 say state switch unicode_strings |
375 | unicode_eval evalbytes current_sub fc | |
376 | ||
d09258e7 RS |
377 | :5.20 say state switch unicode_strings |
378 | unicode_eval evalbytes current_sub fc | |
379 | ||
b530a4ea RS |
380 | :5.22 say state switch unicode_strings |
381 | unicode_eval evalbytes current_sub fc | |
382 | ||
6031f0d2 RS |
383 | :5.24 say state switch unicode_strings |
384 | unicode_eval evalbytes current_sub fc | |
1c2511e0 | 385 | postderef_qq |
6031f0d2 | 386 | |
2c5484a6 RS |
387 | :5.26 say state switch unicode_strings |
388 | unicode_eval evalbytes current_sub fc | |
389 | postderef_qq | |
390 | ||
c35a148e S |
391 | :5.28 say state switch unicode_strings |
392 | unicode_eval evalbytes current_sub fc | |
401d2aaa | 393 | postderef_qq bitwise |
c35a148e | 394 | |
d361a1e6 S |
395 | :5.30 say state switch unicode_strings |
396 | unicode_eval evalbytes current_sub fc | |
397 | postderef_qq bitwise | |
398 | ||
01868d00 FC |
399 | The C<:default> bundle represents the feature set that is enabled before |
400 | any C<use feature> or C<no feature> declaration. | |
a3a91442 JV |
401 | |
402 | Specifying sub-versions such as the C<0> in C<5.14.0> in feature bundles has | |
b22bbcf0 | 403 | no effect. Feature bundles are guaranteed to be the same for all sub-versions. |
bc9b29db | 404 | |
0b25e784 DG |
405 | use feature ":5.14.0"; # same as ":5.14" |
406 | use feature ":5.14.1"; # same as ":5.14" | |
a3a91442 | 407 | |
7dfde25d RGS |
408 | =head1 IMPLICIT LOADING |
409 | ||
0b25e784 DG |
410 | Instead of loading feature bundles by name, it is easier to let Perl do |
411 | implicit loading of a feature bundle for you. | |
412 | ||
413 | There are two ways to load the C<feature> pragma implicitly: | |
7dfde25d RGS |
414 | |
415 | =over 4 | |
416 | ||
417 | =item * | |
418 | ||
0b25e784 DG |
419 | By using the C<-E> switch on the Perl command-line instead of C<-e>. |
420 | That will enable the feature bundle for that version of Perl in the | |
421 | main compilation unit (that is, the one-liner that follows C<-E>). | |
7dfde25d RGS |
422 | |
423 | =item * | |
424 | ||
0b25e784 | 425 | By explicitly requiring a minimum Perl version number for your program, with |
b22bbcf0 | 426 | the C<use VERSION> construct. That is, |
7dfde25d | 427 | |
0b25e784 | 428 | use v5.10.0; |
7dfde25d RGS |
429 | |
430 | will do an implicit | |
431 | ||
39ec54a5 | 432 | no feature ':all'; |
82cfb3a2 | 433 | use feature ':5.10'; |
7dfde25d | 434 | |
b22bbcf0 FC |
435 | and so on. Note how the trailing sub-version |
436 | is automatically stripped from the | |
82cfb3a2 | 437 | version. |
7dfde25d | 438 | |
8d115822 RB |
439 | But to avoid portability warnings (see L<perlfunc/use>), you may prefer: |
440 | ||
441 | use 5.010; | |
442 | ||
443 | with the same effect. | |
444 | ||
0b25e784 | 445 | If the required version is older than Perl 5.10, the ":default" feature |
01868d00 | 446 | bundle is automatically loaded instead. |
70397346 | 447 | |
affe54fa AC |
448 | Unlike C<use feature ":5.12">, saying C<use v5.12> (or any higher version) |
449 | also does the equivalent of C<use strict>; see L<perlfunc/use> for details. | |
450 | ||
7dfde25d RGS |
451 | =back |
452 | ||
0d863452 RH |
453 | =cut |
454 | ||
455 | sub import { | |
22055af9 | 456 | shift; |
36143a0c NC |
457 | |
458 | if (!@_) { | |
0b25e784 | 459 | croak("No features specified"); |
0d863452 | 460 | } |
36143a0c | 461 | |
d3757264 | 462 | __common(1, @_); |
0d863452 RH |
463 | } |
464 | ||
465 | sub unimport { | |
22055af9 | 466 | shift; |
0d863452 | 467 | |
39ec54a5 | 468 | # A bare C<no feature> should reset to the default bundle |
bc9b29db | 469 | if (!@_) { |
39ec54a5 RS |
470 | $^H &= ~($hint_uni8bit|$hint_mask); |
471 | return; | |
bc9b29db RH |
472 | } |
473 | ||
d3757264 NC |
474 | __common(0, @_); |
475 | } | |
476 | ||
477 | ||
478 | sub __common { | |
479 | my $import = shift; | |
0c8d5017 NC |
480 | my $bundle_number = $^H & $hint_mask; |
481 | my $features = $bundle_number != $hint_mask | |
482 | && $feature_bundle{$hint_bundles[$bundle_number >> $hint_shift]}; | |
483 | if ($features) { | |
da5b5421 | 484 | # Features are enabled implicitly via bundle hints. |
d9ee6ccb NC |
485 | # Delete any keys that may be left over from last time. |
486 | delete @^H{ values(%feature) }; | |
487 | $^H |= $hint_mask; | |
488 | for (@$features) { | |
489 | $^H{$feature{$_}} = 1; | |
490 | $^H |= $hint_uni8bit if $_ eq 'unicode_strings'; | |
491 | } | |
da5b5421 | 492 | } |
bc9b29db | 493 | while (@_) { |
0b25e784 DG |
494 | my $name = shift; |
495 | if (substr($name, 0, 1) eq ":") { | |
496 | my $v = substr($name, 1); | |
497 | if (!exists $feature_bundle{$v}) { | |
498 | $v =~ s/^([0-9]+)\.([0-9]+).[0-9]+$/$1.$2/; | |
499 | if (!exists $feature_bundle{$v}) { | |
500 | unknown_feature_bundle(substr($name, 1)); | |
501 | } | |
502 | } | |
503 | unshift @_, @{$feature_bundle{$v}}; | |
504 | next; | |
505 | } | |
36143a0c | 506 | if (!exists $feature{$name}) { |
db629560 FC |
507 | if (exists $noops{$name}) { |
508 | next; | |
509 | } | |
c22e17d0 DIM |
510 | if (!$import && exists $removed{$name}) { |
511 | next; | |
512 | } | |
0b25e784 DG |
513 | unknown_feature($name); |
514 | } | |
d3757264 NC |
515 | if ($import) { |
516 | $^H{$feature{$name}} = 1; | |
517 | $^H |= $hint_uni8bit if $name eq 'unicode_strings'; | |
518 | } else { | |
0b25e784 | 519 | delete $^H{$feature{$name}}; |
1863b879 | 520 | $^H &= ~ $hint_uni8bit if $name eq 'unicode_strings'; |
0b25e784 | 521 | } |
0d863452 | 522 | } |
0d863452 RH |
523 | } |
524 | ||
b42943c4 RGS |
525 | sub unknown_feature { |
526 | my $feature = shift; | |
527 | croak(sprintf('Feature "%s" is not supported by Perl %vd', | |
0b25e784 | 528 | $feature, $^V)); |
b42943c4 RGS |
529 | } |
530 | ||
531 | sub unknown_feature_bundle { | |
532 | my $feature = shift; | |
533 | croak(sprintf('Feature bundle "%s" is not supported by Perl %vd', | |
0b25e784 | 534 | $feature, $^V)); |
b42943c4 RGS |
535 | } |
536 | ||
537 | sub croak { | |
538 | require Carp; | |
539 | Carp::croak(@_); | |
540 | } | |
541 | ||
0d863452 | 542 | 1; |
69bcf1d3 FC |
543 | |
544 | # ex: set ro: |