+# -*- buffer-read-only: t -*-
+# !!!!!!! DO NOT EDIT THIS FILE !!!!!!!
+# This file is built by regen/feature.pl.
+# Any changes made here will be lost!
+
package feature;
-our $VERSION = '1.24';
+our $VERSION = '1.33';
-# (feature name) => (internal name, used in %^H)
-my %feature = (
+our %feature = (
+ fc => 'feature_fc',
say => 'feature_say',
state => 'feature_state',
switch => 'feature_switch',
evalbytes => 'feature_evalbytes',
+ array_base => 'feature_arybase',
current_sub => 'feature___SUB__',
+ lexical_subs => 'feature_lexsubs',
unicode_eval => 'feature_unieval',
unicode_strings => 'feature_unicode',
);
-# These work backwards--the presence of the hint elem disables the feature:
-my %default_feature = (
- array_base => 'feature_no$[',
+our %feature_bundle = (
+ "5.10" => [qw(array_base say state switch)],
+ "5.11" => [qw(array_base say state switch unicode_strings)],
+ "5.15" => [qw(current_sub evalbytes fc say state switch unicode_eval unicode_strings)],
+ "all" => [qw(array_base current_sub evalbytes fc lexical_subs say state switch unicode_eval unicode_strings)],
+ "default" => [qw(array_base)],
);
+$feature_bundle{"5.12"} = $feature_bundle{"5.11"};
+$feature_bundle{"5.13"} = $feature_bundle{"5.11"};
+$feature_bundle{"5.14"} = $feature_bundle{"5.11"};
+$feature_bundle{"5.16"} = $feature_bundle{"5.15"};
+$feature_bundle{"5.17"} = $feature_bundle{"5.15"};
+$feature_bundle{"5.18"} = $feature_bundle{"5.15"};
+$feature_bundle{"5.19"} = $feature_bundle{"5.15"};
+$feature_bundle{"5.20"} = $feature_bundle{"5.15"};
+$feature_bundle{"5.9.5"} = $feature_bundle{"5.10"};
+
+our $hint_shift = 26;
+our $hint_mask = 0x1c000000;
+our @hint_bundles = qw( default 5.10 5.11 5.15 );
+
# This gets set (for now) in $^H as well as in %^H,
# for runtime speed of the uc/lc/ucfirst/lcfirst functions.
# See HINT_UNI_8_BIT in perl.h.
our $hint_uni8bit = 0x00000800;
-# NB. the latest bundle must be loaded by the -E switch (see toke.c)
-
-our %feature_bundle = (
- "default" => [keys %default_feature],
- "5.10" => [qw(say state switch array_base)],
- "5.11" => [qw(say state switch unicode_strings array_base)],
- "5.15" => [qw(say state switch unicode_strings unicode_eval
- evalbytes current_sub)],
-);
-
-# Each of these is the same as the previous bundle
-for(12...14, 16) {
- $feature_bundle{"5.$_"} = $feature_bundle{"5.".($_-1)}
-}
-
-# special case
-$feature_bundle{"5.9.5"} = $feature_bundle{"5.10"};
-
# TODO:
# - think about versioned features (use feature switch => 2)
=head2 Lexical effect
Like other pragmas (C<use strict>, for example), features have a lexical
-effect. C<use feature qw(foo)> will only make the feature "foo" available
+effect. C<use feature qw(foo)> will only make the feature "foo" available
from that point to the end of the enclosing block.
{
}
say "Yet it is here.";
-C<no feature> with no features specified will turn off all features.
+C<no feature> with no features specified will reset to the default group. To
+disable I<all> features (an unusual request!) use C<no feature ':all'>.
=head1 AVAILABLE FEATURES
C<use feature 'switch'> tells the compiler to enable the Perl 6
given/when construct.
-See L<perlsyn/"Switch statements"> for details.
+See L<perlsyn/"Switch Statements"> for details.
This feature is available starting with Perl 5.10.
in all string operations executed within its scope (unless they are also
within the scope of either C<use locale> or C<use bytes>). The same applies
to all regular expressions compiled within the scope, even if executed outside
-it.
+it. It does not change the internal representation of strings, but only how
+they are interpreted.
C<no feature 'unicode_strings'> tells the compiler to use the traditional
Perl semantics wherein the native character set semantics is used unless it is
potentially using Unicode in your program, the
C<use feature 'unicode_strings'> subpragma is B<strongly> recommended.
-This feature is available starting with Perl 5.12, but was not fully
-implemented until Perl 5.14.
+This feature is available starting with Perl 5.12; was almost fully
+implemented in Perl 5.14; and extended in Perl 5.16 to cover C<quotemeta>.
=head2 The 'unicode_eval' and 'evalbytes' features
previous versions, it was simply on all the time, and this pragma knew
nothing about it.
+=head2 The 'fc' feature
+
+C<use feature 'fc'> tells the compiler to enable the C<fc> function,
+which implements Unicode casefolding.
+
+See L<perlfunc/fc> for details.
+
+This feature is available from Perl 5.16 onwards.
+
+=head2 The 'lexical_subs' feature
+
+B<WARNING>: This feature is still experimental and the implementation may
+change in future versions of Perl. For this reason, Perl will
+warn when you use the feature, unless you have explicitly disabled the
+warning:
+
+ no warnings "experimental::lexical_subs";
+
+This enables declaration of subroutines via C<my sub foo>, C<state sub foo>
+and C<our sub foo> syntax. See L<perlsub/Lexical Subroutines> for details.
+
+This feature is available from Perl 5.18 onwards.
+
=head1 FEATURE BUNDLES
It's possible to load multiple features together, using
:5.14 say state switch unicode_strings array_base
:5.16 say state switch unicode_strings
- unicode_eval evalbytes current_sub
+ unicode_eval evalbytes current_sub fc
+
+ :5.18 say state switch unicode_strings
+ unicode_eval evalbytes current_sub fc
+
+ :5.20 say state switch unicode_strings
+ unicode_eval evalbytes current_sub fc
The C<:default> bundle represents the feature set that is enabled before
any C<use feature> or C<no feature> declaration.
will do an implicit
- no feature;
+ no feature ':all';
use feature ':5.10';
and so on. Note how the trailing sub-version
sub import {
my $class = shift;
- if (@_ == 0) {
+
+ if (!@_) {
croak("No features specified");
}
- while (@_) {
- my $name = shift(@_);
- if (substr($name, 0, 1) eq ":") {
- my $v = substr($name, 1);
- if (!exists $feature_bundle{$v}) {
- $v =~ s/^([0-9]+)\.([0-9]+).[0-9]+$/$1.$2/;
- if (!exists $feature_bundle{$v}) {
- unknown_feature_bundle(substr($name, 1));
- }
- }
- unshift @_, @{$feature_bundle{$v}};
- next;
- }
- if (!exists $feature{$name}) {
- if (!exists $default_feature{$name}) {
- unknown_feature($name);
- }
- delete $^H{$default_feature{$name}}; next;
- }
- $^H{$feature{$name}} = 1;
- $^H |= $hint_uni8bit if $name eq 'unicode_strings';
- }
+
+ __common(1, @_);
}
sub unimport {
my $class = shift;
- # A bare C<no feature> should disable *all* features
+ # A bare C<no feature> should reset to the default bundle
if (!@_) {
- delete @^H{ values(%feature) };
- $^H &= ~ $hint_uni8bit;
- @^H{ values(%default_feature) } = (1) x keys %default_feature;
- return;
+ $^H &= ~($hint_uni8bit|$hint_mask);
+ return;
}
+ __common(0, @_);
+}
+
+
+sub __common {
+ my $import = shift;
+ my $bundle_number = $^H & $hint_mask;
+ my $features = $bundle_number != $hint_mask
+ && $feature_bundle{$hint_bundles[$bundle_number >> $hint_shift]};
+ if ($features) {
+ # Features are enabled implicitly via bundle hints.
+ # Delete any keys that may be left over from last time.
+ delete @^H{ values(%feature) };
+ $^H |= $hint_mask;
+ for (@$features) {
+ $^H{$feature{$_}} = 1;
+ $^H |= $hint_uni8bit if $_ eq 'unicode_strings';
+ }
+ }
while (@_) {
my $name = shift;
if (substr($name, 0, 1) eq ":") {
unshift @_, @{$feature_bundle{$v}};
next;
}
- if (!exists($feature{$name})) {
- if (!exists $default_feature{$name}) {
+ if (!exists $feature{$name}) {
unknown_feature($name);
- }
- $^H{$default_feature{$name}} = 1; next;
}
- else {
+ if ($import) {
+ $^H{$feature{$name}} = 1;
+ $^H |= $hint_uni8bit if $name eq 'unicode_strings';
+ } else {
delete $^H{$feature{$name}};
$^H &= ~ $hint_uni8bit if $name eq 'unicode_strings';
}
}
1;
+
+# ex: set ro:
https://perl5.git.perl.org / perl5.git / blobdiff