From: Benoit Daloze <eregontp@...>
Date: 2010-06-07T07:03:30+09:00
Subject: Re: comparing objects

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Hi,

Just wanting to add my thoughts about this (I made a thread about this a few
months ago).

I searched a bit and concluded this:

Array methods using comparison
- with #hash and #eql?
    &, |, uniq(!), -
- with #==
    include?, (r)assoc, count, delete, (r,find_)index
(please say me if I forgot one)

I think Array methods should never have to look at #hash and #eql? methods.
I suppose this is done for performance.

I think this should change, because:
 - it violates POLS
 - it can make unexpected behavior because you defined #hash and #eql? , for
objects which should not need that (when you manage objects in an Array, you
do not expect to need to think about Hash's keys).
 - it is not consistent with other Array's methods

PS: Rein: I saw your implementation of #hash. I think to "add one" is
useless, because #eql? is always used (so even if #hash was always the same,
it would work). It could maybe speed up a bit, but only if you have a lot of
comparison of User and User's instances, which is very unlikely.

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