From: ara.t.howard@...
Date: 2006-12-11T04:54:37+09:00
Subject: Re: defining key equivalence in a hash

On Mon, 11 Dec 2006, Suraj Kurapati wrote:

> Hello,
>
> I'm trying to make two keys equivalent by having their #hash method
> produce the same result. But this does not seem to work:
>
> irb(main):001:0> class K; def hash; 90; end; end
> => nil
> irb(main):002:0> h = {}
> => {}
> irb(main):003:0> h[K.new] = 1
> => 1
> irb(main):004:0> h.key? K.new      # <---- I want this to return true!
> => false
>
> What am I missing?

K#eql?

for example


   harp:~ > cat a.rb
   class K
     attr 'key'
     def initialize() @key = 42 end
     def hash() @key.hash end
     def eql?(other) other.key == @key end
   end

   p K.new => 'which', K.new => 'one'


   harp:~ > ruby a.rb
   {#<K:0xb75cca34 @key=42>=>"one"}

regards.

-a
-- 
if you want others to be happy, practice compassion.
if you want to be happy, practice compassion.  -- the dalai lama