Package::Anon(3) User Contributed Perl Documentation Package::Anon(3)NAMEPackage::Anon - Anonymous packages
SYNOPSIS
my $stash = Package::Anon->new;
$stash->add_method(get_answer => sub { 42 });
my $obj = $stash->bless({});
$obj->get_answer; # 42
DESCRIPTION
This module allows for anonymous packages that are independent of the
main namespace and only available through an object instance, not by
name.
# Declare an anonymous package using new()
my $stash = Package::Anon->new;
# Add behavior to the package
$stash->add_method('get_answer', sub{ return 42; });
# Create an instance of the anonymous package
my $instance = $stash->bless({});
# Call the method
$instance->get_answer(); # returns 42
In "$my_object->do_stuff()" Perl uses a the name of the class
$my_object is blessed into to resolve the function "do_stuff()".
Packages created using Package::Anon exist outside of the "main::"
namespace and cannot be referenced by name. These packages are defined
within stashes that are only accessible through a reference rather than
using a name.
Previous attempts to allow for anonymous packages in Perl use
workarounds that still ultimately result in references by named
packages. Because Package::Anon allows method dispatching without a
name lookup, packages are truly anonymous.
METHODS
new ($name?)
my $stash = Package::Anon->new;
my $stash = Package::Anon->new('Foo');
Create a new anonymous package. The optional $name argument sets the
stash's name. This name only serves as an aid for debugging. The stash
is not reachable from the global symbol table by the given name.
$name defaults to "__ANON__".
bless ($reference)
my $instance = $stash->bless({});
Bless a $reference into the anonymous package.
add_method ($name, $code)
$stash->add_method(foo => sub { return 42; });
Register a new method in the anonymous package. "add_method()" is
provided as a convenience method for adding code symbols to slots in
the anonymous stash. For additional symbol table manipulation, see
"SYMBOL TABLE MANIPULATION".
blessed ($obj)
my $stash = Package::Anon->blessed($obj);
Returns a Package::Anon instance for the package the given $obj is
blessed into, or undef if $obj isn't an object.
install_glob ($name)
my $gv = $stash->install_glob('foo');
Create a glob with the given $name and install it under that $name
within the $stash. The returned glob can be used to install symbols
into the $stash. See "SYMBOL TABLE MANIPULATION" for examples.
EXPERIMENTAL METHODS
These methods interact with the symbol table in ways that could cause
unexpected results in your programs. Please use them with caution.
create_glob ($name)
my $gv = $stash->create_glob('foo');
Creates a new glob with the name $name, pointing to $stash as its
stash. The created glob is not installed into the $stash.
This method implements functionality similar to Symbol::gensym, but
allows you to specify the name of the glob.
SYMBOL TABLE MANIPULATION
This module is intended to create anonymous packages with behavior, not
data members. Support for data members has been documented because the
Glob API supports the addition of data types besides coderefs. Please
use this module with caution when creating data members in your
anonymous packages.
add_method('get_answer', sub {return 42});
is the same as:
my $gv = install_glob('get_answer');
*$gv = sub { return 42 };
For other data types:
*$gv = \$foo # scalar
*$gv = \@foo # array
*$gv = \%foo # hash
Currently, "Package::Anon" instances are blessed stash references, so
the following is possible:
$stash->{$symbol_name} = *$gv;
However, the exact details of how to get a hold of the actual stash
reference might change in the future.
AUTHORS
· Florian Ragwitz <rafl@debian.org>
· Ricardo Signes <rjbs@cpan.org>
· Jesse Luehrs <doy@tozt.net>
· Augustina Blair <auggy@cpan.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2012 by Florian Ragwitz.
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 v5.18.2 2012-08-29 Package::Anon(3)
