# phpman > perldoc > Class::MOP::Package ## NAME [Class::MOP::Package](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3APackage/markdown) - Package Meta Object ## VERSION version 2.2200 ## DESCRIPTION The Package Protocol provides an abstraction of a Perl 5 package. A package is basically namespace, and this module provides methods for looking at and changing that namespace's symbol table. ## METHODS [Class::MOP::Package](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3APackage/markdown)->initialize($package_name, %options) This method creates a new "[Class::MOP::Package](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3APackage/markdown)" instance which represents specified package. If an existing metaclass object exists for the package, that will be returned instead. No options are valid at the package level. [Class::MOP::Package](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3APackage/markdown)->reinitialize($package, %options) This method forcibly removes any existing metaclass for the package before calling "initialize". In contrast to "initialize", you may also pass an existing "[Class::MOP::Package](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3APackage/markdown)" instance instead of just a package name as $package. Do not call this unless you know what you are doing. [Class::MOP::Package](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3APackage/markdown)->create($package, %options) Creates a new "[Class::MOP::Package](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3APackage/markdown)" instance which represents the specified package, and also does some initialization of that package. Currently, this just does the same thing as "initialize", but is overridden in subclasses, such as "[Class::MOP::Class](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3AClass/markdown)". [Class::MOP::Package](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3APackage/markdown)->create_anon(%options) Creates a new anonymous package. Valid keys for %options are: "cache" If this will be "true" (the default is "false"), the instance will be cached in "[Class::MOP](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP/markdown)"'s metaclass cache. "weaken" If this is "true" (the default "true" when cache is "false"), the instance stored in "[Class::MOP](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP/markdown)"'s metaclass cache will be weakened, so that the anonymous package will be garbage collected when the returned instance goes out of scope. $metapackage->is_anon Returns true if the package is an anonymous package. $metapackage->name This is returns the package's name, as passed to the constructor. $metapackage->namespace This returns a hash reference to the package's symbol table. The keys are symbol names and the values are typeglob references. $metapackage->add_package_symbol($variable_name, $initial_value) This method accepts a variable name and an optional initial value. The $variable_name must contain a leading sigil. This method creates the variable in the package's symbol table, and sets it to the initial value if one was provided. $metapackage->get_package_symbol($variable_name) Given a variable name, this method returns the variable as a reference or undef if it does not exist. The $variable_name must contain a leading sigil. $metapackage->get_or_add_package_symbol($variable_name) Given a variable name, this method returns the variable as a reference. If it does not exist, a default value will be generated if possible. The $variable_name must contain a leading sigil. $metapackage->has_package_symbol($variable_name) Returns true if there is a package variable defined for $variable_name. The $variable_name must contain a leading sigil. $metapackage->remove_package_symbol($variable_name) This will remove the package variable specified $variable_name. The $variable_name must contain a leading sigil. $metapackage->remove_package_glob($glob_name) Given the name of a glob, this will remove that glob from the package's symbol table. Glob names do not include a sigil. Removing the glob removes all variables and subroutines with the specified name. $metapackage->list_all_package_symbols($type_filter) This will list all the glob names associated with the current package. These names do not have leading sigils. You can provide an optional type filter, which should be one of 'SCALAR', 'ARRAY', 'HASH', or 'CODE'. $metapackage->get_all_package_symbols($type_filter) This works much like "list_all_package_symbols", but it returns a hash reference. The keys are glob names and the values are references to the value for that name. [Class::MOP::Package](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3APackage/markdown)->meta This will return a [Class::MOP::Class](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3AClass/markdown) instance for this class. ## AUTHORS * Stevan Little <> * Dave Rolsky <> * Jesse Luehrs <> * Shawn M Moore <> * יובל קוג'מן (Yuval Kogman) <> * Karen Etheridge <> * Florian Ragwitz <> * Hans Dieter Pearcey <> * Chris Prather <> * Matt S Trout <> ## COPYRIGHT AND LICENSE This software is copyright (c) 2006 by Infinity Interactive, Inc. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.