The problem with just UNIVERSAL::can($ref,'isa') is that it can return a true value when $ref isn't even a reference. So you really have to make multiple tests:

if(  ! ref($r)  ) {
    # no reference at all
} elsif(  ! UNIVERSAL::can($r,'can')  ) {
    # unblessed ref
} else {
    # blessed ref
}
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or just:

    if(  ref($r)  &&  UNIVERSAL::can($r,'can')  ) {
        # blessed ref
    }
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or

    if(  ref($r)  &&  eval { $r->can('can') }  ) {
        # blessed ref
    }
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and I can't make a convincing case for one style over the other at the moment.

And, yes, it would be nice if there were less overloaded versions of these things so that blessed returned the package that a reference was blessed into and ref just always returned the type of thing. That was a certainly a design mistake IMO.

        - tye (but my friends call me "Tye")