phpman > perldoc > namespace::clean(3pm)

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.

   Late binding caveat
    Note that the technique used by this module relies on perl having resolved all names to actual
    code references during the compilation of a scope. While this is almost always what the
    interpreter does, there are some exceptions, notably the sort SUBNAME style of the "sort"
    built-in invocation. The following example will not work, because "sort" does not try to resolve
    the function name to an actual code reference until runtime.

     use MyApp::Utils 'my_sorter';
     use namespace::clean;

     my @sorted = sort my_sorter @list;

    You need to work around this by forcing a compile-time resolution like so:

     use MyApp::Utils 'my_sorter';
     use namespace::clean;

     my $my_sorter_cref = \&my_sorter;

     my @sorted = sort $my_sorter_cref @list;

  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 AT 474.at>

    *   Florian Ragwitz <rafl AT debian.org>

    *   Jesse Luehrs <doy AT tozt.net>

    *   Peter Rabbitson <ribasushi AT cpan.org>

    *   Father Chrysostomos <sprout AT 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.