I think this is what you want:
#! perl -w
use strict;
use diagnostics;
use Carp;
sub iterFac {
my $max = shift;
my $val = shift || 1;
my $cnt = shift || 1;
Carp::cluck("we are currently here:");
return $val if $cnt > $max;
#iterFac($max, $val*$cnt, ++$cnt);
@_ = ($max, $val*$cnt, ++$cnt);
goto &iterFac;
}
my $x = iterFac(5);
print "Factorial 5 = $x\n";
Note how I've used Carp::cluck to show where we are at all times. If you remove the # from the iterFac call and comment out the @_ assignment and the goto, and run this, you'll see how it cluck's that it gets 5 subroutine calls deep. But as-is, the cluck always shows only a single subroutine deep.
I think that's what you're looking for, but someone with an actual CS degree may show me wrong ;-)