Object::Extend - add and override per-object methods
use Object::Extend qw(extend);
my $foo1 = Foo->new;
my $foo2 = Foo->new;
extend $foo1 => {
bar => sub { ... },
};
$foo1->bar; # OK
$foo2->bar; # errorThis module allows objects to be extended with per-object methods, similar to
the use of singleton methods
in Ruby. Object methods are added to an object-specific shim class (known as an
eigenclass), which extends the object's original class. The original class is
left unchanged.
extend takes an object and a hash or hashref of method names and method
values (coderefs) and adds the methods to the object's shim class. The object
is then blessed into this class and returned.
It can be used in standalone statements:
extend $object, foo => sub { ... }, bar => \&bar;Or expressions:
return extend($object => { bar => sub { ... } })->bar;In both cases, extend operates on and returns the supplied object, i.e. a new
object is never created. If a new object is needed, it can be created manually,
e.g.:
my $object2 = Object->new($object1);
my $object3 = clone($object1);
extend($object2, foo => sub { ... })->foo;
return extend($object3 => ...);Objects can be extended multiple times with new or overridden methods:
# call the original method
my $object = Foo->new;
$object->foo;
# override the original method
extend $object, foo => sub { ... };
$object->foo;
# add a new method
extend $object, bar => sub { ... };
$object->bar;This sub can optionally be imported to make the use of extend more
descriptive. It takes and returns a hashref of method names/coderefs:
use Object::Extend qw(extend with);
extend $object => with { foo => sub { ... } };Every extended object's shim class includes an additional (empty) class in its
@ISA which indicates that the object has been extended. The name of this
class can be accessed by importing the SINGLETON constant, e.g.:
use Object::Extend qw(SINGLETON);
if ($object->isa(SINGLETON)) { ... } # object extended with object-specific methods0.4.0
- Class::Monadic
- Class::SingletonMethod
- MooseX::SingletonMethod
- MouseX::SingletonMethod
- Object::Accessor
- SingletonMethod
Copyright © 2013-2021 by chocolateboy.
This is free software; you can redistribute it and/or modify it under the terms of the Artistic License 2.0.