Subj : Re: anyone know of a language where nonexistent functions return
To   : comp.programming
From : Jonathan Bartlett
Date : Fri Jul 22 2005 03:16 pm

> So i'm intrigued now - what do folks use the feature for?

Another application I thought of is as a wrapper to another class.

For example, if I wanted to trace all of the calls made on an object, I 
could create a tracer class:

package Tracer;

sub new
{
	my ($class, $traced_obj) = @_;

	my $self = { TRACED_OBJ => $traced_obj };
	bless $self, $class;
	return $self;
}

sub AUTOLOAD
{
	my $name = our $AUTOLOAD;
	*$AUTOLOAD = sub { my $self = shift;  print STDERR "Calling $name\n"; 
$self->$name(@_); }
	goto &*AUTOLOAD;
}

Then I could use it like this:

use Tracer;
my $obj = new Tracer(new SomeOtherClass);
$obj->whatever(); /* gives a trace and then calls "whatever" on the 
original object -- Completely API compatible with the original object */

Also you could create sort of "dynamic subclasses" which allow you to 
subclass a wide variety of objects (I used to be able to think of 
situations where this would be useful, but not at the moment).

Jon
----
Learn to program using Linux assembly language
http://www.cafeshops.com/bartlettpublish.8640017

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