Subj : Re: anyone know of a language where nonexistent functions return no error?
To   : comp.programming
From : gswork
Date : Tue Jul 26 2005 07:19 am



Jonathan Bartlett wrote:
> > 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).

thanks for these examples - this latter one is something i can see the
benefit of as a handy 'in code' development tool.

.