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1 | package Package::Stash; |
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2 | use strict; |
3 | use warnings; |
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4 | # ABSTRACT: routines for manipulating stashes |
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5 | |
6 | use Carp qw(confess); |
7 | use Scalar::Util qw(reftype); |
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8 | use Symbol; |
9 | # before 5.12, assigning to the ISA glob would make it lose its magical ->isa |
10 | # powers |
11 | use constant BROKEN_ISA_ASSIGNMENT => ($] < 5.012); |
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12 | |
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13 | =head1 SYNOPSIS |
14 | |
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15 | my $stash = Package::Stash->new('Foo'); |
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16 | $stash->add_package_symbol('%foo', {bar => 1}); |
17 | # $Foo::foo{bar} == 1 |
18 | $stash->has_package_symbol('$foo') # false |
19 | my $namespace = $stash->namespace; |
20 | *{ $namespace->{foo} }{HASH} # {bar => 1} |
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21 | |
22 | =head1 DESCRIPTION |
23 | |
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24 | Manipulating stashes (Perl's symbol tables) is occasionally necessary, but |
25 | incredibly messy, and easy to get wrong. This module hides all of that behind a |
26 | simple API. |
27 | |
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28 | NOTE: Most methods in this class require a variable specification that includes |
29 | a sigil. If this sigil is absent, it is assumed to represent the IO slot. |
30 | |
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31 | =method new $package_name |
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32 | |
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33 | Creates a new C<Package::Stash> object, for the package given as the only |
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34 | argument. |
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35 | |
36 | =cut |
37 | |
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38 | sub new { |
39 | my $class = shift; |
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40 | my ($package) = @_; |
41 | my $namespace; |
42 | { |
43 | no strict 'refs'; |
44 | # supposedly this caused a bug in earlier perls, but I can't reproduce |
45 | # it, so re-enabling the caching |
46 | $namespace = \%{$package . '::'}; |
47 | } |
48 | return bless { |
49 | 'package' => $package, |
50 | 'namespace' => $namespace, |
51 | }, $class; |
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52 | } |
53 | |
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54 | =method name |
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55 | |
56 | Returns the name of the package that this object represents. |
57 | |
58 | =cut |
59 | |
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60 | sub name { |
61 | return $_[0]->{package}; |
62 | } |
63 | |
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64 | =method namespace |
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65 | |
66 | Returns the raw stash itself. |
67 | |
68 | =cut |
69 | |
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70 | sub namespace { |
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71 | return $_[0]->{namespace}; |
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72 | } |
73 | |
74 | { |
75 | my %SIGIL_MAP = ( |
76 | '$' => 'SCALAR', |
77 | '@' => 'ARRAY', |
78 | '%' => 'HASH', |
79 | '&' => 'CODE', |
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80 | '' => 'IO', |
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81 | ); |
82 | |
83 | sub _deconstruct_variable_name { |
84 | my ($self, $variable) = @_; |
85 | |
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86 | (defined $variable && length $variable) |
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87 | || confess "You must pass a variable name"; |
88 | |
89 | my $sigil = substr($variable, 0, 1, ''); |
90 | |
56a29840 |
91 | if (exists $SIGIL_MAP{$sigil}) { |
92 | return ($variable, $sigil, $SIGIL_MAP{$sigil}); |
93 | } |
94 | else { |
95 | return ("${sigil}${variable}", '', $SIGIL_MAP{''}); |
96 | } |
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97 | } |
98 | } |
99 | |
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100 | =method add_package_symbol $variable $value %opts |
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101 | |
102 | Adds a new package symbol, for the symbol given as C<$variable>, and optionally |
103 | gives it an initial value of C<$value>. C<$variable> should be the name of |
104 | variable including the sigil, so |
105 | |
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106 | Package::Stash->new('Foo')->add_package_symbol('%foo') |
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107 | |
108 | will create C<%Foo::foo>. |
109 | |
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110 | Valid options (all optional) are C<filename>, C<first_line_num>, and |
111 | C<last_line_num>. |
112 | |
113 | C<$opts{filename}>, C<$opts{first_line_num}>, and C<$opts{last_line_num}> can |
114 | be used to indicate where the symbol should be regarded as having been defined. |
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115 | Currently these values are only used if the symbol is a subroutine ('C<&>' |
c61010aa |
116 | sigil) and only if C<$^P & 0x10> is true, in which case the special C<%DB::sub> |
117 | hash is updated to record the values of C<filename>, C<first_line_num>, and |
118 | C<last_line_num> for the subroutine. If these are not passed, their values are |
119 | inferred (as much as possible) from C<caller> information. |
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120 | |
121 | This is especially useful for debuggers and profilers, which use C<%DB::sub> to |
122 | determine where the source code for a subroutine can be found. See |
123 | L<http://perldoc.perl.org/perldebguts.html#Debugger-Internals> for more |
124 | information about C<%DB::sub>. |
125 | |
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126 | =cut |
127 | |
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128 | sub _valid_for_type { |
129 | my $self = shift; |
130 | my ($value, $type) = @_; |
131 | if ($type eq 'HASH' || $type eq 'ARRAY' |
132 | || $type eq 'IO' || $type eq 'CODE') { |
133 | return reftype($value) eq $type; |
134 | } |
135 | else { |
136 | my $ref = reftype($value); |
137 | return !defined($ref) || $ref eq 'SCALAR' || $ref eq 'REF' || $ref eq 'LVALUE'; |
138 | } |
139 | } |
140 | |
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141 | sub add_package_symbol { |
640de369 |
142 | my ($self, $variable, $initial_value, %opts) = @_; |
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143 | |
144 | my ($name, $sigil, $type) = ref $variable eq 'HASH' |
145 | ? @{$variable}{qw[name sigil type]} |
146 | : $self->_deconstruct_variable_name($variable); |
147 | |
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148 | my $pkg = $self->name; |
149 | |
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150 | if (@_ > 2) { |
151 | $self->_valid_for_type($initial_value, $type) |
152 | || confess "$initial_value is not of type $type"; |
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153 | |
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154 | # cheap fail-fast check for PERLDBf_SUBLINE and '&' |
155 | if ($^P and $^P & 0x10 && $sigil eq '&') { |
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156 | my $filename = $opts{filename}; |
157 | my $first_line_num = $opts{first_line_num}; |
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158 | |
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159 | (undef, $filename, $first_line_num) = caller |
4ada57e0 |
160 | if not defined $filename; |
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161 | |
162 | my $last_line_num = $opts{last_line_num} || ($first_line_num ||= 0); |
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163 | |
164 | # http://perldoc.perl.org/perldebguts.html#Debugger-Internals |
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165 | $DB::sub{$pkg . '::' . $name} = "$filename:$first_line_num-$last_line_num"; |
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166 | } |
167 | } |
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168 | |
169 | no strict 'refs'; |
170 | no warnings 'redefine', 'misc', 'prototype'; |
171 | *{$pkg . '::' . $name} = ref $initial_value ? $initial_value : \$initial_value; |
172 | } |
173 | |
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174 | =method remove_package_glob $name |
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175 | |
176 | Removes all package variables with the given name, regardless of sigil. |
177 | |
178 | =cut |
179 | |
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180 | sub remove_package_glob { |
181 | my ($self, $name) = @_; |
182 | no strict 'refs'; |
183 | delete ${$self->name . '::'}{$name}; |
184 | } |
185 | |
186 | # ... these functions deal with stuff on the namespace level |
187 | |
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188 | =method has_package_symbol $variable |
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189 | |
190 | Returns whether or not the given package variable (including sigil) exists. |
191 | |
192 | =cut |
193 | |
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194 | sub has_package_symbol { |
195 | my ($self, $variable) = @_; |
196 | |
197 | my ($name, $sigil, $type) = ref $variable eq 'HASH' |
198 | ? @{$variable}{qw[name sigil type]} |
199 | : $self->_deconstruct_variable_name($variable); |
200 | |
201 | my $namespace = $self->namespace; |
202 | |
203 | return unless exists $namespace->{$name}; |
204 | |
205 | my $entry_ref = \$namespace->{$name}; |
206 | if (reftype($entry_ref) eq 'GLOB') { |
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207 | return defined *{$entry_ref}{$type}; |
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208 | } |
209 | else { |
210 | # a symbol table entry can be -1 (stub), string (stub with prototype), |
211 | # or reference (constant) |
212 | return $type eq 'CODE'; |
213 | } |
214 | } |
215 | |
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216 | =method get_package_symbol $variable |
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217 | |
218 | Returns the value of the given package variable (including sigil). |
219 | |
220 | =cut |
221 | |
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222 | sub get_package_symbol { |
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223 | my ($self, $variable, %opts) = @_; |
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224 | |
225 | my ($name, $sigil, $type) = ref $variable eq 'HASH' |
226 | ? @{$variable}{qw[name sigil type]} |
227 | : $self->_deconstruct_variable_name($variable); |
228 | |
229 | my $namespace = $self->namespace; |
230 | |
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231 | if (!exists $namespace->{$name}) { |
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232 | if ($opts{vivify}) { |
233 | if ($type eq 'ARRAY') { |
234 | if (BROKEN_ISA_ASSIGNMENT) { |
235 | $self->add_package_symbol( |
236 | $variable, |
237 | $name eq 'ISA' ? () : ([]) |
238 | ); |
239 | } |
240 | else { |
241 | $self->add_package_symbol($variable, []); |
242 | } |
243 | } |
244 | elsif ($type eq 'HASH') { |
245 | $self->add_package_symbol($variable, {}); |
246 | } |
247 | elsif ($type eq 'SCALAR') { |
248 | $self->add_package_symbol($variable); |
249 | } |
250 | elsif ($type eq 'IO') { |
251 | $self->add_package_symbol($variable, Symbol::geniosym); |
252 | } |
253 | elsif ($type eq 'CODE') { |
254 | confess "Don't know how to vivify CODE variables"; |
255 | } |
256 | else { |
257 | confess "Unknown type $type in vivication"; |
258 | } |
5d3589c8 |
259 | } |
e55803fc |
260 | else { |
dc378b60 |
261 | if ($type eq 'CODE') { |
262 | # this effectively "de-vivifies" the code slot. if we don't do |
263 | # this, referencing the coderef at the end of this function |
264 | # will cause perl to auto-vivify a stub coderef in the slot, |
265 | # which isn't what we want |
266 | $self->add_package_symbol($variable); |
267 | } |
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268 | } |
30d1a098 |
269 | } |
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270 | |
271 | my $entry_ref = \$namespace->{$name}; |
272 | |
273 | if (ref($entry_ref) eq 'GLOB') { |
274 | return *{$entry_ref}{$type}; |
275 | } |
276 | else { |
277 | if ($type eq 'CODE') { |
278 | no strict 'refs'; |
279 | return \&{ $self->name . '::' . $name }; |
280 | } |
281 | else { |
282 | return undef; |
283 | } |
284 | } |
285 | } |
286 | |
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287 | =method get_or_add_package_symbol $variable |
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288 | |
289 | Like C<get_package_symbol>, except that it will return an empty hashref or |
290 | arrayref if the variable doesn't exist. |
291 | |
292 | =cut |
293 | |
294 | sub get_or_add_package_symbol { |
295 | my $self = shift; |
296 | $self->get_package_symbol(@_, vivify => 1); |
297 | } |
298 | |
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299 | =method remove_package_symbol $variable |
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300 | |
301 | Removes the package variable described by C<$variable> (which includes the |
302 | sigil); other variables with the same name but different sigils will be |
303 | untouched. |
304 | |
305 | =cut |
306 | |
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307 | sub remove_package_symbol { |
308 | my ($self, $variable) = @_; |
309 | |
310 | my ($name, $sigil, $type) = ref $variable eq 'HASH' |
311 | ? @{$variable}{qw[name sigil type]} |
312 | : $self->_deconstruct_variable_name($variable); |
313 | |
314 | # FIXME: |
9a3d1390 |
315 | # no doubt this is grossly inefficient and |
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316 | # could be done much easier and faster in XS |
317 | |
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318 | my ($scalar_desc, $array_desc, $hash_desc, $code_desc, $io_desc) = ( |
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319 | { sigil => '$', type => 'SCALAR', name => $name }, |
320 | { sigil => '@', type => 'ARRAY', name => $name }, |
321 | { sigil => '%', type => 'HASH', name => $name }, |
322 | { sigil => '&', type => 'CODE', name => $name }, |
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323 | { sigil => '', type => 'IO', name => $name }, |
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324 | ); |
325 | |
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326 | my ($scalar, $array, $hash, $code, $io); |
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327 | if ($type eq 'SCALAR') { |
328 | $array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc); |
329 | $hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc); |
330 | $code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc); |
b1a00d0e |
331 | $io = $self->get_package_symbol($io_desc) if $self->has_package_symbol($io_desc); |
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332 | } |
333 | elsif ($type eq 'ARRAY') { |
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334 | $scalar = $self->get_package_symbol($scalar_desc); |
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335 | $hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc); |
336 | $code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc); |
b1a00d0e |
337 | $io = $self->get_package_symbol($io_desc) if $self->has_package_symbol($io_desc); |
f10f6217 |
338 | } |
339 | elsif ($type eq 'HASH') { |
42fa5cfc |
340 | $scalar = $self->get_package_symbol($scalar_desc); |
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341 | $array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc); |
342 | $code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc); |
b1a00d0e |
343 | $io = $self->get_package_symbol($io_desc) if $self->has_package_symbol($io_desc); |
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344 | } |
345 | elsif ($type eq 'CODE') { |
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346 | $scalar = $self->get_package_symbol($scalar_desc); |
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347 | $array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc); |
348 | $hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc); |
b1a00d0e |
349 | $io = $self->get_package_symbol($io_desc) if $self->has_package_symbol($io_desc); |
350 | } |
351 | elsif ($type eq 'IO') { |
42fa5cfc |
352 | $scalar = $self->get_package_symbol($scalar_desc); |
b1a00d0e |
353 | $array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc); |
354 | $hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc); |
355 | $code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc); |
f10f6217 |
356 | } |
357 | else { |
358 | confess "This should never ever ever happen"; |
359 | } |
360 | |
361 | $self->remove_package_glob($name); |
362 | |
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363 | $self->add_package_symbol($scalar_desc => $scalar); |
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364 | $self->add_package_symbol($array_desc => $array) if defined $array; |
365 | $self->add_package_symbol($hash_desc => $hash) if defined $hash; |
366 | $self->add_package_symbol($code_desc => $code) if defined $code; |
b1a00d0e |
367 | $self->add_package_symbol($io_desc => $io) if defined $io; |
f10f6217 |
368 | } |
369 | |
988beb41 |
370 | =method list_all_package_symbols $type_filter |
683542f5 |
371 | |
372 | Returns a list of package variable names in the package, without sigils. If a |
373 | C<type_filter> is passed, it is used to select package variables of a given |
374 | type, where valid types are the slots of a typeglob ('SCALAR', 'CODE', 'HASH', |
375 | etc). |
376 | |
377 | =cut |
378 | |
f10f6217 |
379 | sub list_all_package_symbols { |
380 | my ($self, $type_filter) = @_; |
381 | |
382 | my $namespace = $self->namespace; |
383 | return keys %{$namespace} unless defined $type_filter; |
384 | |
385 | # NOTE: |
9a3d1390 |
386 | # or we can filter based on |
f10f6217 |
387 | # type (SCALAR|ARRAY|HASH|CODE) |
388 | if ($type_filter eq 'CODE') { |
389 | return grep { |
25c87f5c |
390 | # any non-typeglob in the symbol table is a constant or stub |
391 | ref(\$namespace->{$_}) ne 'GLOB' |
392 | # regular subs are stored in the CODE slot of the typeglob |
393 | || defined(*{$namespace->{$_}}{CODE}); |
f10f6217 |
394 | } keys %{$namespace}; |
395 | } else { |
396 | return grep { *{$namespace->{$_}}{$type_filter} } keys %{$namespace}; |
397 | } |
398 | } |
f4979588 |
399 | |
0992f4ec |
400 | =head1 BUGS |
401 | |
402 | No known bugs. |
403 | |
404 | Please report any bugs through RT: email |
405 | C<bug-package-stash at rt.cpan.org>, or browse to |
406 | L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Package-Stash>. |
407 | |
f4979588 |
408 | =head1 SEE ALSO |
409 | |
f4979588 |
410 | =over 4 |
411 | |
988beb41 |
412 | =item * L<Class::MOP::Package> |
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413 | |
988beb41 |
414 | This module is a factoring out of code that used to live here |
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415 | |
416 | =back |
417 | |
0992f4ec |
418 | =head1 SUPPORT |
419 | |
420 | You can find this documentation for this module with the perldoc command. |
421 | |
422 | perldoc Package::Stash |
423 | |
424 | You can also look for information at: |
425 | |
426 | =over 4 |
427 | |
428 | =item * AnnoCPAN: Annotated CPAN documentation |
429 | |
430 | L<http://annocpan.org/dist/Package-Stash> |
431 | |
432 | =item * CPAN Ratings |
433 | |
434 | L<http://cpanratings.perl.org/d/Package-Stash> |
435 | |
436 | =item * RT: CPAN's request tracker |
437 | |
438 | L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Package-Stash> |
439 | |
440 | =item * Search CPAN |
441 | |
442 | L<http://search.cpan.org/dist/Package-Stash> |
443 | |
444 | =back |
445 | |
446 | =head1 AUTHOR |
447 | |
448 | Jesse Luehrs <doy at tozt dot net> |
449 | |
450 | Mostly copied from code from L<Class::MOP::Package>, by Stevan Little and the |
451 | Moose Cabal. |
452 | |
f4979588 |
453 | =cut |
454 | |
455 | 1; |