/usr/share/perl/5.14.2/feature.pm is in perl-base 5.14.2-6ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 | package feature;
our $VERSION = '1.20';
# (feature name) => (internal name, used in %^H)
my %feature = (
switch => 'feature_switch',
say => "feature_say",
state => "feature_state",
unicode_strings => "feature_unicode",
);
# 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)
my %feature_bundle = (
"5.10" => [qw(switch say state)],
"5.11" => [qw(switch say state unicode_strings)],
"5.12" => [qw(switch say state unicode_strings)],
"5.13" => [qw(switch say state unicode_strings)],
"5.14" => [qw(switch say state unicode_strings)],
);
# special case
$feature_bundle{"5.9.5"} = $feature_bundle{"5.10"};
# TODO:
# - think about versioned features (use feature switch => 2)
sub import {
my $class = shift;
if (@_ == 0) {
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}) {
unknown_feature($name);
}
$^H{$feature{$name}} = 1;
$^H |= $hint_uni8bit if $name eq 'unicode_strings';
}
}
sub unimport {
my $class = shift;
# A bare C<no feature> should disable *all* features
if (!@_) {
delete @^H{ values(%feature) };
$^H &= ~ $hint_uni8bit;
return;
}
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{$name})) {
unknown_feature($name);
}
else {
delete $^H{$feature{$name}};
$^H &= ~ $hint_uni8bit if $name eq 'unicode_strings';
}
}
}
sub unknown_feature {
my $feature = shift;
croak(sprintf('Feature "%s" is not supported by Perl %vd',
$feature, $^V));
}
sub unknown_feature_bundle {
my $feature = shift;
croak(sprintf('Feature bundle "%s" is not supported by Perl %vd',
$feature, $^V));
}
sub croak {
require Carp;
Carp::croak(@_);
}
1;
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