I think it should be
if (UNIVERSAL::can($ref,'isa')) { ...
But I see the point now.
As UNIVERSAL is the parent of every
object (blessed reference) and it implements method 'isa', every
beast that know how to call
isa method must be an object.
Update:
No, $r->can('isa') won't work (as I mentioned in the other reply) because
if $r is not blessed, it will die on 'unblessed reference' error.
UNIVERSAL::can($r,'isa') is real solution.
Update2:
Even if I do refcheck, situation is the same. I just cannot call any
method on non-blessed reference, not even the can() method.
Consider $r={}; you cannot do $r->can() because $r is not blessed.
And that is what I want to know, if $r is blessed or not. I know that it is a reference.
Catching a die exception with eval is TIMTOWDI, but it does not look good to me :-)