NAME

       Object::Extend - add and override per-object methods

SYNOPSIS

           use Object::Extend qw(extend);

           my $foo1 = Foo->new;
           my $foo2 = Foo->new;

           extend $foo1 => {
               bar => sub { ... },
           };

           $foo1->bar; # OK
           $foo2->bar; # error

DESCRIPTION

       This module allows objects to be extended with per-object methods, similar to the use of
       singleton methods <http://madebydna.com/all/code/2011/06/24/eigenclasses-demystified.html>
       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.

   EXPORTS
       extend

       "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;

       with

       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 { ... } };

       SINGLETON

       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 methods

VERSION

       0.4.0

SEE ALSO

       •   Class::SingletonMethod

       •   MooseX::SingletonMethod

       •   MouseX::SingletonMethod

       •   SingletonMethod <https://github.com/tom-lpsd/p5-singleton-method>

AUTHOR

       chocolateboy <chocolate@cpan.org>

COPYRIGHT AND LICENSE

       Copyright (C) 2013 by chocolateboy

       This library is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself, either Perl version 5.14.2 or, at your option, any later version of
       Perl 5 you may have available.