/usr/share/perl5/Perl6/Export/Attrs.pm is in libperl6-export-attrs-perl 0.000005-1.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 | package Perl6::Export::Attrs;
our $VERSION = '0.000005';
use warnings;
use strict;
use Carp;
use Attribute::Handlers;
use PadWalker qw( var_name peek_my );
my %IMPORT_for;
sub import {
my $caller = caller;
no strict 'refs';
*{$caller.'::import'} = \&_generic_import;
*{$caller.'::IMPORT'} = sub (&) { $IMPORT_for{$caller} = shift };
for my $var_type (qw( SCALAR ARRAY HASH CODE )) {
*{$caller.'::MODIFY_'.$var_type.'_ATTRIBUTES'} = \&_generic_handler;
}
return;
}
my %tagsets_for;
my %is_exported_from;
my %named_tagsets_for;
my %decl_loc_for;
my %name_of;
my $IDENT = '[^\W\d]\w*';
sub _generic_handler {
my ($package, $referent, @attrs) = @_;
ATTR:
for my $attr (@attrs) {
($attr||=q{}) =~ s/\A Export (?: \( (.*) \) )? \z/$1||q{}/exms
or next ATTR;
my @tagsets = grep {length $_} split m/ \s+,?\s* | ,\s* /xms, $attr;
my (undef, $file, $line) = caller(1);
$file =~ s{.*/}{}xms;
if (my @bad_tags = grep {!m/\A :$IDENT \z/xms} @tagsets) {
die 'Bad tagset',
(@bad_tags==1?' ':'s '),
"in :Export attribute at '$file' line $line: [@bad_tags]\n";
}
my $tagsets = $tagsets_for{$package} ||= {};
for my $tagset (@tagsets) {
push @{ $tagsets->{$tagset} }, $referent;
}
push @{ $tagsets->{':ALL'} }, $referent;
$is_exported_from{$package}{$referent} = 1;
$decl_loc_for{$referent} = "$file line $line";
$name_of{$referent} = _get_lexical_name($referent);
undef $attr;
}
return grep {defined $_} @attrs;
}
my %desc_for = (
SCALAR => 'lexical scalar variable',
ARRAY => 'lexical array variable',
HASH => 'lexical hash variable',
CODE => 'anonymous subroutine',
);
my %hint_for = (
SCALAR => "(declare the variable with 'our' instead of 'my')",
ARRAY => "(declare the variable with 'our' instead of 'my')",
HASH => "(declare the variable with 'our' instead of 'my')",
CODE => "(specify a name after the 'sub' keyword)",
);
sub _get_lexical_name {
my ($var_ref) = @_;
return if ref $var_ref eq 'CODE';
SEARCH:
for my $up_level (1..(~0>>1)-1) {
my $sym_tab_ref = eval { peek_my($up_level) }
or last SEARCH;
for my $var_name (keys %{$sym_tab_ref}) {
return $var_name if $var_ref == $sym_tab_ref->{$var_name};
}
}
return;
}
sub _invert_tagset {
my ($package, $tagset) = @_;
my %inverted_tagset;
for my $tag (keys %{$tagset}) {
for my $sub_ref (@{$tagset->{$tag}}) {
my $type = ref $sub_ref;
my $sym = Attribute::Handlers::findsym($package, $sub_ref, $type)
|| $name_of{$sub_ref}
or die "Can't export $desc_for{$type} ",
"at $decl_loc_for{$sub_ref}\n$hint_for{$type}\n";
if (ref $sym) {
$sym = *{$sym}{NAME};
}
$inverted_tagset{$tag}{$sym} = $sub_ref;
}
}
return \%inverted_tagset;
}
my %type_for = qw( $ SCALAR @ ARRAY % HASH );
# Reusable import() subroutine for all packages...
sub _generic_import {
my $package = shift;
my $tagset
= $named_tagsets_for{$package}
||= _invert_tagset($package, $tagsets_for{$package});
my $is_exported = $is_exported_from{$package};
my $errors;
my %request;
my $subs_ref;
my $args_supplied = @_;
my $argno = 0;
REQUEST:
while ($argno < @_) {
my $request = $_[$argno];
if (my ($sub_name) = $request =~ m/\A &? ($IDENT) (?:\(\))? \z/xms) {
if (exists $request{$sub_name}) {
splice @_, $argno, 1;
next REQUEST;
}
no strict 'refs';
no warnings 'once';
if (my $sub_ref = *{$package.'::'.$sub_name}{CODE}) {
if ($is_exported->{$sub_ref}) {
$request{$sub_name} = $sub_ref;
splice @_, $argno, 1;
next REQUEST;
}
}
}
elsif (my ($sigil, $name) = $request =~ m/\A ([\$\@%])($IDENT) \z/xms) {
next REQUEST if exists $request{$sigil.$name};
no strict 'refs';
no warnings 'once';
if (my $var_ref = *{$package.'::'.$name}{$type_for{$sigil}}) {
if ($is_exported->{$var_ref}) {
$request{$sigil.$name} = $var_ref;
splice @_, $argno, 1;
next REQUEST;
}
}
}
elsif ($request =~ m/\A :$IDENT \z/xms
and $subs_ref = $tagset->{$request}) {
@request{keys %{$subs_ref}} = values %{$subs_ref};
splice @_, $argno, 1;
next REQUEST;
}
$errors .= " $request";
$argno++;
}
# Report unexportable requests...
my $real_import = $IMPORT_for{$package};
croak "$package does not export:$errors\nuse $package failed"
if $errors && !$real_import;
if (!$args_supplied) {
%request = %{$tagset->{':DEFAULT'}||={}}
}
my $mandatory = $tagset->{':MANDATORY'} ||= {};
@request{ keys %{$mandatory} } = values %{$mandatory};
my $caller = caller;
for my $sub_name (keys %request) {
no strict 'refs';
my ($sym_name) = $sub_name =~ m{\A [\$\@&%]? (.*)}xms;
*{$caller.'::'.$sym_name} = $request{$sub_name};
}
if ($real_import) {
my $idx=0;
while ($idx < @_) {
if (defined $_[$idx]) { $idx++ }
else { splice @_, $idx, 1 }
}
goto &{$real_import};
}
return;
}
1; # Magic true value required at end of module
__END__
=head1 NAME
Perl6::Export::Attrs - The Perl 6 'is export(...)' trait as a Perl 5 attribute
=head1 VERSION
This document describes Perl6::Export::Attrs version 0.000005
=head1 SYNOPSIS
package Some::Module;
use Perl6::Export::Attrs;
# Export &foo by default, when explicitly requested,
# or when the ':ALL' export set is requested...
sub foo :Export(:DEFAULT) {
print "phooo!";
}
# Export &var by default, when explicitly requested,
# or when the ':bees', ':pubs', or ':ALL' export set is requested...
# the parens after 'is export' are like the parens of a qw(...)
sub bar :Export(:DEFAULT :bees :pubs) {
print "baaa!";
}
# Export &baz when explicitly requested
# or when the ':bees' or ':ALL' export set is requested...
sub baz :Export(:bees) {
print "baassss!";
}
# Always export &qux
# (no matter what else is explicitly or implicitly requested)
sub qux :Export(:MANDATORY) {
print "quuuuuuuuux!";
}
# Allow the constant $PI to be exported when requested...
use Readonly;
Readonly our $PI :Export => 355/113;
# Allow the variable $EPSILON to be always exported...
our $EPSILON :Export( :MANDATORY ) = 0.00001;
sub IMPORT {
# This subroutine is called when the module is used (as usual),
# but it is called after any export requests have been handled.
};
=head1 DESCRIPTION
Implements a Perl 5 native version of what the Perl 6 symbol export mechanism
will look like (with some unavoidable restrictions).
It's very straightforward:
=over
=item *
If you want a subroutine or package variable to be capable of being exported
(when explicitly requested in the C<use> arguments), you mark it with
the C<:Export> attribute.
=item *
If you want a subroutine or package variable to be automatically exported when
the module is used (without specific overriding arguments), you mark it
with the C<:Export(:DEFAULT)> attribute.
=item *
If you want a subroutine or package variable to be automatically exported when
the module is used (even if the user specifies overriding arguments),
you mark it with the C<:Export(:MANDATORY)> attribute.
=item *
If the subroutine or package variable should also be exported when particular
export groups are requested, you add the names of those export groups to
the attribute's argument list.
=back
That's it.
=head2 C<IMPORT> blocks
Perl 6 replaces the C<import> subroutine with an C<IMPORT> block. It's
analogous to a C<BEGIN> or C<END> block, except that it's executed every
time the corresponding module is C<use>'d.
The C<IMPORT> block is passed the argument list that was specified on
the C<use> line that loaded the corresponding module, minus the
arguments that were used to specify exports.
Note that, due to limitations in Perl 5, the C<IMPORT> block provided by this
module must be terminated by a semi-colon, unless it is the last statement in
the file.
=head1 DIAGNOSTICS
=over
=item %s does not export: %s\nuse %s failed
You tried to import the specified subroutine or package variable, but
the module didn't export it. Often caused by a misspelling, or
forgetting to add an C<:Export> attribute to the definition of the
subroutine or variable in question.
=item Bad tagset in :Export attribute at %s line %s: [%s]
You tried to import a collection of items via a tagset, but the module
didn't export any subroutines under that tagset. Is the tagset name
misspelled (maybe you forgot the colon?).
=item Can't export lexical %s variable at %s
The module can only export package variables. You applied the C<:Export>
marker to a non-package variable (almost certainly to a lexical). Change
the variable's C<my> declarator to an C<our>.
=item Can't export anonymous subroutine at %s
Although you I<can> apply the C<:Export> marker to an anonymous subroutine,
it rarely makes any sense to do so, since that subroutine can't be
exported without a name to export it as. Either give the subroutine a
name, or make sure it's aliased to a named typeglob at compile-time (or,
at least, before it's exported).
=back
=head1 CONFIGURATION AND ENVIRONMENT
Perl6::Export::Attrs requires no configuration files or environment variables.
=head1 DEPENDENCIES
This module requires the Attribute::Handlers module to handle the attributes.
=head1 INCOMPATIBILITIES
This module cannot be used with the Memoize CPAN module,
because memoization replaces the original subroutine
with a wrapper. Because the C<:Export> attribute is
applied to the original (not the wrapper), the memoized
wrapper is not found by the exporter mechanism.
=head1 BUGS AND LIMITATIONS
No bugs have been reported.
Note that the module does not support exporting lexical variables,
since there is no way for the exporter mechanism to determine the name
of a lexical and hence to export it.
Nor does this module support the numerous addition export modes that
Perl 6 offers, such as export-as-lexical or export-as-state.
Please report any bugs or feature requests to
C<bug-perl6-export-attrs@rt.cpan.org>, or through the web interface at
L<http://rt.cpan.org>.
=head1 AUTHOR
Damian Conway C<< <DCONWAY@cpan.org> >>
=head1 LICENCE AND COPYRIGHT
Copyright (c) 2005, Damian Conway C<< <DCONWAY@cpan.org> >>. All rights reserved.
This module is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
=head1 DISCLAIMER OF WARRANTY
BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER
EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH
YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
NECESSARY SERVICING, REPAIR, OR CORRECTION.
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE
LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL,
OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE
THE SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A
FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF
SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGES.
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