http://www.perlmonks.org?node_id=354012


in reply to Confused by OO & tie

Think of 'tie' as a way to have an object act like a hash. Perl calls those methods on the object to implement the hash functionality. 
my $value = $hash{$key};
my $object = tied %hash;
$value = $object->FETCH($key);

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Most objects are blessed references to hashes; they are implemented as hashes internally. Perl does not have a mechanism for having named attributes (ie instance variables) of an object. People use hashes to store the internal state of the object.

It is quite possible to have a tied hash implemented using a hash reference object.

In Section Seekers of Perl Wisdom