From: Alex LeDonne <aledonne.listmail@...>
Date: 2006-12-27T03:14:48+09:00
Subject: Re: Hash with two identical keys?

On 12/26/06, Trans <transfire@gmail.com> wrote:
> >From Facets' multiton.rb (which is primarily Floran Franks' work), I'm
> getting somthing that doesn't make any sense:
>
>         POOLS[self] ||= {}
>         p POOLS[self].class
>         p POOLS[self].keys
>
> Is outputing:
>
>   Hash
>   [[{:strip_comments=>false}], [{:strip_comments=>false}]]
>
> How can two identical keys be in a hash?
>
> T.
>
irb(main):005:0> bob = [{:whee => false}]
=> [{:whee=>false}]
irb(main):006:0> bob.hash
=> 23244868
irb(main):007:0> roger = [{:whee => false}]
=> [{:whee=>false}]
irb(main):008:0> roger.hash
=> 23235888
irb(main):009:0> bob.eql? roger
=> false
irb(main):010:0> bob[0].eql? roger[0]
=> false
irb(main):011:0> bob[0].hash
=> 23244870
irb(main):012:0> roger[0].hash
=> 23235890

I think it boils down to: there is no Hash#hash which inspects the
contents - Hash inherits Object#hash which is Object#object_id, and
the two hashes, while they appear to have the same contents, are not
the same object. So the keys are not "identical".

-A