UNIVERSAL::ref(3) User Contributed Perl Documentation UNIVERSAL::ref(3)NAMEUNIVERSAL::ref - Turns ref() into a multimethod
SYNOPSIS
# True! Wrapper pretends to be Thing.
ref( Wrapper->new( Thing->new ) )
eq ref( Thing->new );
package Thing;
sub new { bless [], shift }
package Wrapper;
sub new {
my ($class,$proxy) = @_;
bless \ $proxy, $class;
}
sub ref {
my $self = shift @_;
return $$self;
}
DESCRIPTION
This module changes the behavior of the builtin function ref(). If
ref() is called on an object that has requested an overloaded ref, the
object's "->ref" method will be called and its return value used
instead.
USING
To enable this feature for a class, "use UNIVERSAL::ref" in your class.
Here is a sample proxy module.
package Pirate;
# Pirate pretends to be a Privateer
use UNIVERSAL::ref;
sub new { bless {}, shift }
sub ref { return 'Privateer' }
Anywhere you call "ref($obj)" on a "Pirate" object, it will allow
"Pirate" to lie and pretend to be something else.
METHODS
import
A pragma for ref()-enabling your class. This adds the calling class
name to a global list of ref()-enabled classes.
package YourClass;
use UNIVERSAL::ref;
sub ref { ... }
unimport
A pragma for ref()-disabling your class. This removes the calling
class name from a global list of ref()-enabled classes.
TODO
Currently UNIVERSAL::ref must be installed before any ref() calls that
are to be affected.
I think ref() always occurs in an implicit scalar context. There is no
accomodation for list context.
UNIVERSAL::ref probably shouldn't allow a module to lie to itself. Or
should it?
ACKNOWLEDGEMENTS
ambrus for the excellent idea to overload defined() to allow Perl 5 to
have Perl 6's "interesting values of undef."
chromatic for pointing out how utterly broken ref() is. This fix covers
its biggest hole.
AUTHOR
Joshua ben Jore - jjore@cpan.org
LICENSE
The standard Artistic / GPL license most other perl code is typically
using.
perl v5.14.1 2011-01-23 UNIVERSAL::ref(3)
