2 namespace::clean - Keep imports and functions out of your namespace
12 use Carp qw(croak); # 'croak' will be removed
14 sub bar { 23 } # 'bar' will be removed
16 # remove all previously defined functions
19 sub baz { bar() } # 'baz' still defined, 'bar' still bound
21 # begin to collection function names from here again
24 sub quux { baz() } # 'quux' will be removed
26 # remove all functions defined after the 'no' unimport
29 # Will print: 'No', 'No', 'Yes' and 'No'
30 print +(__PACKAGE__->can('croak') ? 'Yes' : 'No'), "\n";
31 print +(__PACKAGE__->can('bar') ? 'Yes' : 'No'), "\n";
32 print +(__PACKAGE__->can('baz') ? 'Yes' : 'No'), "\n";
33 print +(__PACKAGE__->can('quux') ? 'Yes' : 'No'), "\n";
38 Keeping packages clean
39 When you define a function, or import one, into a Perl package, it will
40 naturally also be available as a method. This does not per se cause
41 problems, but it can complicate subclassing and, for example, plugin
42 classes that are included via multiple inheritance by loading them as
45 The "namespace::clean" pragma will remove all previously declared or
46 imported symbols at the end of the current package's compile cycle.
47 Functions called in the package itself will still be bound by their
48 name, but they won't show up as methods on your class or instances.
50 By unimporting via "no" you can tell "namespace::clean" to start
51 collecting functions for the next "use namespace::clean;" specification.
53 You can use the "-except" flag to tell "namespace::clean" that you don't
54 want it to remove a certain function or method. A common use would be a
55 module exporting an "import" method along with some functions:
57 use ModuleExportingImport;
58 use namespace::clean -except => [qw( import )];
60 If you just want to "-except" a single sub, you can pass it directly.
61 For more than one value you have to use an array reference.
63 Explicitely removing functions when your scope is compiled
64 It is also possible to explicitely tell "namespace::clean" what packages
65 to remove when the surrounding scope has finished compiling. Here is an
71 # blessed NOT available
74 use Scalar::Util qw( blessed );
75 use namespace::clean qw( blessed );
81 # blessed NOT available
84 When using "namespace::clean" together with Moose you want to keep the
85 installed "meta" method. So your classes should look like:
89 use namespace::clean -except => 'meta';
92 Same goes for Moose::Role.
94 Cleaning other packages
95 You can tell "namespace::clean" that you want to clean up another
96 package instead of the one importing. To do this you have to pass in the
97 "-cleanee" option like this:
99 package My::MooseX::namespace::clean;
102 use namespace::clean (); # no cleanup, just load
105 namespace::clean->import(
106 -cleanee => scalar(caller),
111 If you don't care about "namespace::clean"s discover-and-"-except"
112 logic, and just want to remove subroutines, try "clean_subroutines".
115 You shouldn't need to call any of these. Just "use" the package at the
119 This exposes the actual subroutine-removal logic.
121 namespace::clean->clean_subroutines($cleanee, qw( subA subB ));
123 will remove "subA" and "subB" from $cleanee. Note that this will remove
124 the subroutines immediately and not wait for scope end. If you want to
125 have this effect at a specific time (e.g. "namespace::clean" acts on
126 scope compile end) it is your responsibility to make sure it runs at
130 Makes a snapshot of the current defined functions and installs a
131 B::Hooks::EndOfScope hook in the current scope to invoke the cleanups.
134 This method will be called when you do a
138 It will start a new section of code that defines functions to clean up.
141 This returns a reference to a hash in a passed package containing
142 information about function names included and excluded from removal.
145 Takes a class as argument and returns all currently defined functions in
146 it as a hash reference with the function name as key and a typeglob
147 reference to the symbol as value.
149 IMPLEMENTATION DETAILS
150 This module works through the effect that a
152 delete $SomePackage::{foo};
154 will remove the "foo" symbol from $SomePackage for run time lookups
155 (e.g., method calls) but will leave the entry alive to be called by
156 already resolved names in the package itself. "namespace::clean" will
157 restore and therefor in effect keep all glob slots that aren't "CODE".
159 A test file has been added to the perl core to ensure that this
160 behaviour will be stable in future releases.
162 Just for completeness sake, if you want to remove the symbol completely,
169 Robert 'phaylon' Sedlacek "<rs@474.at>", with many thanks to Matt S
170 Trout for the inspiration on the whole idea.
173 This program is free software; you can redistribute it and/or modify it
174 under the same terms as perl itself.