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1 | package Package::Stash; |
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2 | use strict; |
3 | use warnings; |
4 | |
5 | use Carp qw(confess); |
6 | use Scalar::Util qw(reftype); |
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7 | |
8 | =head1 NAME |
9 | |
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10 | Package::Stash - routines for manipulating stashes |
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11 | |
12 | =head1 SYNOPSIS |
13 | |
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14 | my $stash = Package::Stash->new('Foo'); |
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15 | $stash->add_package_symbol('%foo', {bar => 1}); |
16 | # $Foo::foo{bar} == 1 |
17 | $stash->has_package_symbol('$foo') # false |
18 | my $namespace = $stash->namespace; |
19 | *{ $namespace->{foo} }{HASH} # {bar => 1} |
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20 | |
21 | =head1 DESCRIPTION |
22 | |
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23 | Manipulating stashes (Perl's symbol tables) is occasionally necessary, but |
24 | incredibly messy, and easy to get wrong. This module hides all of that behind a |
25 | simple API. |
26 | |
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27 | NOTE: Most methods in this class require a variable specification that includes |
28 | a sigil. If this sigil is absent, it is assumed to represent the IO slot. |
29 | |
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30 | =head1 METHODS |
31 | |
32 | =cut |
33 | |
34 | =head2 new $package_name |
35 | |
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36 | Creates a new C<Package::Stash> object, for the package given as the only |
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37 | argument. |
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38 | |
39 | =cut |
40 | |
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41 | sub new { |
42 | my $class = shift; |
43 | my ($namespace) = @_; |
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44 | return bless { 'package' => $namespace }, $class; |
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45 | } |
46 | |
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47 | =head2 name |
48 | |
49 | Returns the name of the package that this object represents. |
50 | |
51 | =cut |
52 | |
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53 | sub name { |
54 | return $_[0]->{package}; |
55 | } |
56 | |
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57 | =head2 namespace |
58 | |
59 | Returns the raw stash itself. |
60 | |
61 | =cut |
62 | |
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63 | sub namespace { |
64 | # NOTE: |
65 | # because of issues with the Perl API |
66 | # to the typeglob in some versions, we |
67 | # need to just always grab a new |
68 | # reference to the hash here. Ideally |
69 | # we could just store a ref and it would |
70 | # Just Work, but oh well :\ |
71 | no strict 'refs'; |
72 | return \%{$_[0]->name . '::'}; |
73 | } |
74 | |
75 | { |
76 | my %SIGIL_MAP = ( |
77 | '$' => 'SCALAR', |
78 | '@' => 'ARRAY', |
79 | '%' => 'HASH', |
80 | '&' => 'CODE', |
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81 | '' => 'IO', |
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82 | ); |
83 | |
84 | sub _deconstruct_variable_name { |
85 | my ($self, $variable) = @_; |
86 | |
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87 | (defined $variable && length $variable) |
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88 | || confess "You must pass a variable name"; |
89 | |
90 | my $sigil = substr($variable, 0, 1, ''); |
91 | |
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92 | if (exists $SIGIL_MAP{$sigil}) { |
93 | return ($variable, $sigil, $SIGIL_MAP{$sigil}); |
94 | } |
95 | else { |
96 | return ("${sigil}${variable}", '', $SIGIL_MAP{''}); |
97 | } |
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98 | } |
99 | } |
100 | |
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101 | =head2 add_package_symbol $variable $value $filename $firstlinenum $lastlinenum |
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102 | |
103 | Adds a new package symbol, for the symbol given as C<$variable>, and optionally |
104 | gives it an initial value of C<$value>. C<$variable> should be the name of |
105 | variable including the sigil, so |
106 | |
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107 | Package::Stash->new('Foo')->add_package_symbol('%foo') |
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108 | |
109 | will create C<%Foo::foo>. |
110 | |
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111 | The optional $filename, $firstlinenum, and $lastlinenum arguments can be used |
112 | to indicate where the symbol should be regarded as having been defined. |
113 | Currently these values are only used if the symbol is a subroutine ('C<&>' |
114 | sigil) and only if C<$^P & 0x10> is true. In which case the special |
115 | C<%DB::sub> hash is updated to record the values of $filename, $firstlinenum, |
116 | and $lastlinenum for the subroutine. |
117 | |
118 | This is especially useful for debuggers and profilers, which use C<%DB::sub> to |
119 | determine where the source code for a subroutine can be found. See |
120 | L<http://perldoc.perl.org/perldebguts.html#Debugger-Internals> for more |
121 | information about C<%DB::sub>. |
122 | |
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123 | =cut |
124 | |
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125 | sub _valid_for_type { |
126 | my $self = shift; |
127 | my ($value, $type) = @_; |
128 | if ($type eq 'HASH' || $type eq 'ARRAY' |
129 | || $type eq 'IO' || $type eq 'CODE') { |
130 | return reftype($value) eq $type; |
131 | } |
132 | else { |
133 | my $ref = reftype($value); |
134 | return !defined($ref) || $ref eq 'SCALAR' || $ref eq 'REF' || $ref eq 'LVALUE'; |
135 | } |
136 | } |
137 | |
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138 | sub add_package_symbol { |
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139 | my ($self, $variable, $initial_value) = @_; # extra args unpacked below |
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140 | |
141 | my ($name, $sigil, $type) = ref $variable eq 'HASH' |
142 | ? @{$variable}{qw[name sigil type]} |
143 | : $self->_deconstruct_variable_name($variable); |
144 | |
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145 | my $pkg = $self->name; |
146 | |
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147 | if (@_ > 2) { |
148 | $self->_valid_for_type($initial_value, $type) |
149 | || confess "$initial_value is not of type $type"; |
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150 | |
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151 | # cheap fail-fast check for PERLDBf_SUBLINE and '&' |
152 | if ($^P and $^P & 0x10 && $sigil eq '&') { |
153 | my (undef, undef, undef, $filename, $firstlinenum, $lastlinenum) = @_; |
154 | |
155 | (undef, $filename, $firstlinenum) = caller |
156 | if not defined $filename; |
157 | $lastlinenum = $firstlinenum ||= 0 |
158 | if not defined $lastlinenum; |
159 | |
160 | # http://perldoc.perl.org/perldebguts.html#Debugger-Internals |
161 | $DB::sub{$pkg . '::' . $name} = "$filename:$firstlinenum-$lastlinenum"; |
162 | } |
163 | } |
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164 | |
165 | no strict 'refs'; |
166 | no warnings 'redefine', 'misc', 'prototype'; |
167 | *{$pkg . '::' . $name} = ref $initial_value ? $initial_value : \$initial_value; |
168 | } |
169 | |
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170 | =head2 remove_package_glob $name |
171 | |
172 | Removes all package variables with the given name, regardless of sigil. |
173 | |
174 | =cut |
175 | |
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176 | sub remove_package_glob { |
177 | my ($self, $name) = @_; |
178 | no strict 'refs'; |
179 | delete ${$self->name . '::'}{$name}; |
180 | } |
181 | |
182 | # ... these functions deal with stuff on the namespace level |
183 | |
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184 | =head2 has_package_symbol $variable |
185 | |
186 | Returns whether or not the given package variable (including sigil) exists. |
187 | |
188 | =cut |
189 | |
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190 | sub has_package_symbol { |
191 | my ($self, $variable) = @_; |
192 | |
193 | my ($name, $sigil, $type) = ref $variable eq 'HASH' |
194 | ? @{$variable}{qw[name sigil type]} |
195 | : $self->_deconstruct_variable_name($variable); |
196 | |
197 | my $namespace = $self->namespace; |
198 | |
199 | return unless exists $namespace->{$name}; |
200 | |
201 | my $entry_ref = \$namespace->{$name}; |
202 | if (reftype($entry_ref) eq 'GLOB') { |
203 | if ( $type eq 'SCALAR' ) { |
204 | return defined ${ *{$entry_ref}{SCALAR} }; |
205 | } |
206 | else { |
207 | return defined *{$entry_ref}{$type}; |
208 | } |
209 | } |
210 | else { |
211 | # a symbol table entry can be -1 (stub), string (stub with prototype), |
212 | # or reference (constant) |
213 | return $type eq 'CODE'; |
214 | } |
215 | } |
216 | |
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217 | =head2 get_package_symbol $variable |
218 | |
219 | Returns the value of the given package variable (including sigil). |
220 | |
221 | =cut |
222 | |
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223 | sub get_package_symbol { |
224 | my ($self, $variable) = @_; |
225 | |
226 | my ($name, $sigil, $type) = ref $variable eq 'HASH' |
227 | ? @{$variable}{qw[name sigil type]} |
228 | : $self->_deconstruct_variable_name($variable); |
229 | |
230 | my $namespace = $self->namespace; |
231 | |
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232 | if (!exists $namespace->{$name}) { |
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233 | # assigning to the result of this function like |
234 | # @{$stash->get_package_symbol('@ISA')} = @new_ISA |
235 | # makes the result not visible until the variable is explicitly |
236 | # accessed... in the case of @ISA, this might never happen |
237 | # for instance, assigning like that and then calling $obj->isa |
238 | # will fail. see t/005-isa.t |
239 | if ($type eq 'ARRAY' && $name ne 'ISA') { |
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240 | $self->add_package_symbol($variable, []); |
241 | } |
242 | elsif ($type eq 'HASH') { |
243 | $self->add_package_symbol($variable, {}); |
244 | } |
245 | else { |
246 | # FIXME |
247 | $self->add_package_symbol($variable) |
248 | } |
30d1a098 |
249 | } |
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250 | |
251 | my $entry_ref = \$namespace->{$name}; |
252 | |
253 | if (ref($entry_ref) eq 'GLOB') { |
254 | return *{$entry_ref}{$type}; |
255 | } |
256 | else { |
257 | if ($type eq 'CODE') { |
258 | no strict 'refs'; |
259 | return \&{ $self->name . '::' . $name }; |
260 | } |
261 | else { |
262 | return undef; |
263 | } |
264 | } |
265 | } |
266 | |
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267 | =head2 remove_package_symbol $variable |
268 | |
269 | Removes the package variable described by C<$variable> (which includes the |
270 | sigil); other variables with the same name but different sigils will be |
271 | untouched. |
272 | |
273 | =cut |
274 | |
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275 | sub remove_package_symbol { |
276 | my ($self, $variable) = @_; |
277 | |
278 | my ($name, $sigil, $type) = ref $variable eq 'HASH' |
279 | ? @{$variable}{qw[name sigil type]} |
280 | : $self->_deconstruct_variable_name($variable); |
281 | |
282 | # FIXME: |
283 | # no doubt this is grossly inefficient and |
284 | # could be done much easier and faster in XS |
285 | |
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286 | my ($scalar_desc, $array_desc, $hash_desc, $code_desc, $io_desc) = ( |
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287 | { sigil => '$', type => 'SCALAR', name => $name }, |
288 | { sigil => '@', type => 'ARRAY', name => $name }, |
289 | { sigil => '%', type => 'HASH', name => $name }, |
290 | { sigil => '&', type => 'CODE', name => $name }, |
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291 | { sigil => '', type => 'IO', name => $name }, |
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292 | ); |
293 | |
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294 | my ($scalar, $array, $hash, $code, $io); |
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295 | if ($type eq 'SCALAR') { |
296 | $array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc); |
297 | $hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc); |
298 | $code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc); |
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299 | $io = $self->get_package_symbol($io_desc) if $self->has_package_symbol($io_desc); |
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300 | } |
301 | elsif ($type eq 'ARRAY') { |
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302 | $scalar = $self->get_package_symbol($scalar_desc); |
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303 | $hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc); |
304 | $code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc); |
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305 | $io = $self->get_package_symbol($io_desc) if $self->has_package_symbol($io_desc); |
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306 | } |
307 | elsif ($type eq 'HASH') { |
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308 | $scalar = $self->get_package_symbol($scalar_desc); |
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309 | $array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc); |
310 | $code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc); |
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311 | $io = $self->get_package_symbol($io_desc) if $self->has_package_symbol($io_desc); |
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312 | } |
313 | elsif ($type eq 'CODE') { |
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314 | $scalar = $self->get_package_symbol($scalar_desc); |
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315 | $array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc); |
316 | $hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc); |
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317 | $io = $self->get_package_symbol($io_desc) if $self->has_package_symbol($io_desc); |
318 | } |
319 | elsif ($type eq 'IO') { |
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320 | $scalar = $self->get_package_symbol($scalar_desc); |
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321 | $array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc); |
322 | $hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc); |
323 | $code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc); |
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324 | } |
325 | else { |
326 | confess "This should never ever ever happen"; |
327 | } |
328 | |
329 | $self->remove_package_glob($name); |
330 | |
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331 | $self->add_package_symbol($scalar_desc => $scalar); |
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332 | $self->add_package_symbol($array_desc => $array) if defined $array; |
333 | $self->add_package_symbol($hash_desc => $hash) if defined $hash; |
334 | $self->add_package_symbol($code_desc => $code) if defined $code; |
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335 | $self->add_package_symbol($io_desc => $io) if defined $io; |
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336 | } |
337 | |
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338 | =head2 list_all_package_symbols $type_filter |
339 | |
340 | Returns a list of package variable names in the package, without sigils. If a |
341 | C<type_filter> is passed, it is used to select package variables of a given |
342 | type, where valid types are the slots of a typeglob ('SCALAR', 'CODE', 'HASH', |
343 | etc). |
344 | |
345 | =cut |
346 | |
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347 | sub list_all_package_symbols { |
348 | my ($self, $type_filter) = @_; |
349 | |
350 | my $namespace = $self->namespace; |
351 | return keys %{$namespace} unless defined $type_filter; |
352 | |
353 | # NOTE: |
354 | # or we can filter based on |
355 | # type (SCALAR|ARRAY|HASH|CODE) |
356 | if ($type_filter eq 'CODE') { |
357 | return grep { |
358 | (ref($namespace->{$_}) |
359 | ? (ref($namespace->{$_}) eq 'SCALAR') |
360 | : (ref(\$namespace->{$_}) eq 'GLOB' |
361 | && defined(*{$namespace->{$_}}{CODE}))); |
362 | } keys %{$namespace}; |
363 | } else { |
364 | return grep { *{$namespace->{$_}}{$type_filter} } keys %{$namespace}; |
365 | } |
366 | } |
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367 | |
368 | =head1 BUGS |
369 | |
370 | No known bugs. |
371 | |
372 | Please report any bugs through RT: email |
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373 | C<bug-package-stash at rt.cpan.org>, or browse to |
374 | L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Package-Stash>. |
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375 | |
376 | =head1 SEE ALSO |
377 | |
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378 | L<Class::MOP::Package> - this module is a factoring out of code that used to |
379 | live here |
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380 | |
381 | =head1 SUPPORT |
382 | |
383 | You can find this documentation for this module with the perldoc command. |
384 | |
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385 | perldoc Package::Stash |
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386 | |
387 | You can also look for information at: |
388 | |
389 | =over 4 |
390 | |
391 | =item * AnnoCPAN: Annotated CPAN documentation |
392 | |
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393 | L<http://annocpan.org/dist/Package-Stash> |
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394 | |
395 | =item * CPAN Ratings |
396 | |
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397 | L<http://cpanratings.perl.org/d/Package-Stash> |
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398 | |
399 | =item * RT: CPAN's request tracker |
400 | |
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401 | L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Package-Stash> |
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402 | |
403 | =item * Search CPAN |
404 | |
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405 | L<http://search.cpan.org/dist/Package-Stash> |
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406 | |
407 | =back |
408 | |
409 | =head1 AUTHOR |
410 | |
411 | Jesse Luehrs <doy at tozt dot net> |
412 | |
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413 | Mostly copied from code from L<Class::MOP::Package>, by Stevan Little and the |
414 | Moose Cabal. |
415 | |
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416 | =head1 COPYRIGHT AND LICENSE |
417 | |
418 | This software is copyright (c) 2010 by Jesse Luehrs. |
419 | |
420 | This is free software; you can redistribute it and/or modify it under |
421 | the same terms as perl itself. |
422 | |
423 | =cut |
424 | |
425 | 1; |