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namespace::clean(3)                  User Contributed Perl Documentation                 namespace::clean(3)



NAME
       namespace::clean - Keep imports and functions out of your namespace

SYNOPSIS
         package Foo;
         use warnings;
         use strict;

         use Carp qw(croak);   # 'croak' will be removed

         sub bar { 23 }        # 'bar' will be removed

         # remove all previously defined functions
         use namespace::clean;

         sub baz { bar() }     # 'baz' still defined, 'bar' still bound

         # begin to collection function names from here again
         no namespace::clean;

         sub quux { baz() }    # 'quux' will be removed

         # remove all functions defined after the 'no' unimport
         use namespace::clean;

         # Will print: 'No', 'No', 'Yes' and 'No'
         print +(__PACKAGE__->can('croak') ? 'Yes' : 'No'), "\n";
         print +(__PACKAGE__->can('bar')   ? 'Yes' : 'No'), "\n";
         print +(__PACKAGE__->can('baz')   ? 'Yes' : 'No'), "\n";
         print +(__PACKAGE__->can('quux')  ? 'Yes' : 'No'), "\n";

         1;

DESCRIPTION
   Keeping packages clean
       When you define a function, or import one, into a Perl package, it will naturally also be available
       as a method. This does not per se cause problems, but it can complicate subclassing and, for example,
       plugin classes that are included via multiple inheritance by loading them as base classes.

       The "namespace::clean" pragma will remove all previously declared or imported symbols at the end of
       the current package's compile cycle.  Functions called in the package itself will still be bound by
       their name, but they won't show up as methods on your class or instances.

       By unimporting via "no" you can tell "namespace::clean" to start collecting functions for the next
       "use namespace::clean;" specification.

       You can use the "-except" flag to tell "namespace::clean" that you don't want it to remove a certain
       function or method. A common use would be a module exporting an "import" method along with some
       functions:

         use ModuleExportingImport;
         use namespace::clean -except => [qw( import )];

       If you just want to "-except" a single sub, you can pass it directly.  For more than one value you
       have to use an array reference.

   Explicitly removing functions when your scope is compiled
       It is also possible to explicitly tell "namespace::clean" what packages to remove when the
       surrounding scope has finished compiling. Here is an example:

         package Foo;
         use strict;

         # blessed NOT available

         sub my_class {
             use Scalar::Util qw( blessed );
             use namespace::clean qw( blessed );

             # blessed available
             return blessed shift;
         }

         # blessed NOT available

   Moose
       When using "namespace::clean" together with Moose you want to keep the installed "meta" method. So
       your classes should look like:

         package Foo;
         use Moose;
         use namespace::clean -except => 'meta';
         ...

       Same goes for Moose::Role.

   Cleaning other packages
       You can tell "namespace::clean" that you want to clean up another package instead of the one
       importing. To do this you have to pass in the "-cleanee" option like this:

         package My::MooseX::namespace::clean;
         use strict;

         use namespace::clean (); # no cleanup, just load

         sub import {
             namespace::clean->import(
               -cleanee => scalar(caller),
               -except  => 'meta',
             );
         }

       If you don't care about "namespace::clean"s discover-and-"-except" logic, and just want to remove
       subroutines, try "clean_subroutines".

METHODS
   clean_subroutines
       This exposes the actual subroutine-removal logic.

         namespace::clean->clean_subroutines($cleanee, qw( subA subB ));

       will remove "subA" and "subB" from $cleanee. Note that this will remove the subroutines immediately
       and not wait for scope end. If you want to have this effect at a specific time (e.g.
       "namespace::clean" acts on scope compile end) it is your responsibility to make sure it runs at that
       time.

   import
       Makes a snapshot of the current defined functions and installs a B::Hooks::EndOfScope hook in the
       current scope to invoke the cleanups.

   unimport
       This method will be called when you do a

         no namespace::clean;

       It will start a new section of code that defines functions to clean up.

   get_class_store
       This returns a reference to a hash in a passed package containing information about function names
       included and excluded from removal.

   get_functions
       Takes a class as argument and returns all currently defined functions in it as a hash reference with
       the function name as key and a typeglob reference to the symbol as value.

IMPLEMENTATION DETAILS
       This module works through the effect that a

         delete $SomePackage::{foo};

       will remove the "foo" symbol from $SomePackage for run time lookups (e.g., method calls) but will
       leave the entry alive to be called by already resolved names in the package itself.
       "namespace::clean" will restore and therefor in effect keep all glob slots that aren't "CODE".

       A test file has been added to the perl core to ensure that this behaviour will be stable in future
       releases.

       Just for completeness sake, if you want to remove the symbol completely, use "undef" instead.

SEE ALSO
       B::Hooks::EndOfScope

THANKS
       Many thanks to Matt S Trout for the inspiration on the whole idea.

AUTHORS
       •   Robert 'phaylon' Sedlacek <rs@474.at>

       •   Florian Ragwitz <rafl@debian.org>

       •   Jesse Luehrs <doy@tozt.net>

       •   Peter Rabbitson <ribasushi@cpan.org>

       •   Father Chrysostomos <sprout@cpan.org>

COPYRIGHT AND LICENSE
       This software is copyright (c) 2011 by "AUTHORS"

       This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5
       programming language system itself.



perl v5.16.2                                     2012-03-11                              namespace::clean(3)