I am a bit confused by the statement “there isn't an anonymous hash per se”. Do you mean that the concept doesn't exist in Perl, or that it isn't evidenced in this code? Both seem false to me. (The docs explicitly call hashrefs created via { ... } anonymous hashes, and there's certainly one of those in the OP's code.) Do you just mean that it's not useful to think of anonymous hashes as different from hashrefs?
Comment on Re^2: Simulating user defined data types
My fumbled point was that what is being used is a hash ref and whatever anonymity existed in its creation is irrelevant and only confusing. I'd only want to bring anonymity into the discussion if the code looked like this: record(100,1000,10)->{max}