in reply to How to make a fingerprint from an Object

I would use Data::UUID to generate a universal unique identifier during object creation; you would store that object identifier and use it later for comparison; in fact there is no reason to compute object fingerprint later.

package Class; use strict; use warnings; use Data::UUID; sub new { my $class = shift; my $uuid = Data::UUID->new; return bless { some => 'data', object_signature => $uuid->create_str(), }, $class; } sub object_signature { shift->{object_signature}; } 1;

HTH, Valerio