From: Daniel Martin <martin@...>
Date: 2006-06-28T03:16:48+09:00
Subject: Re: Speaking of eql?

"Molitor, Stephen L" <Stephen.L.Molitor@erac.com> writes:

> I would reword that slightly.  You should override hash if you eql?.
> But not if you only override '==', as '==' is not involved in hashes or
> the hash contract.

The problem with that is that the default definition of eql? is:

def eql?(other)
  self == other
end

So if you override ==, then you need to override either eql? (to have
it mean the same as Object#eql?) or hash.

My very strong recommendation, if you're only going to override one of
those, would be to override hash (rather than simply overriding eql?
to mean the same as equal?), since otherwise Hash objects with your
objects as key won't behave properly, and neither will Set s of your
objects.