From: Todd Benson <caduceass@...>
Date: 2007-07-25T03:27:01+09:00
Subject: Re: object equivalence

On 7/24/07, Andrew Hume <andrew@research.att.com> wrote:
> i have two objects, a and b, both of the same class.
> i believe they have the same contents, but
>         a.eql?(b) returns false
>
> if i write a method xxx that returns as a string the value of every
> field
> (much as to_s does), then a.xxx.hash == b.xxx.hash.
> i believe this latter shows a and b are equivalent; o why
> doesn't eql? agree?

eql? is just a method and therefore depends on the implementing
object.  By default, eql? returns true only if the objects being
compared are the _same_ object.  And then, each class typically
overrides eql? to do as the developer sees fit.

Todd