From: Pit Capitain <pit@...>
Date: 2007-01-30T17:21:27+09:00
Subject: Re: Sane #hash implementation?

Shot (Piotr Szotkowski) schrieb:
> Eric Hodel:
> 
>> On Jan 29, 2007, at 14:38, Shot (Piotr Szotkowski) wrote:
> 
>>> I�m stuck when it comes to Block#hash, though; I need these to be true:
>>> Block.new.hash == Block.new.hash
>>> Block.new([1,2]).hash == Block.new([1,2]).hash
> 
>> Try:
> 
>> class Block
>>   def hash
>>     to_a.hash
>>   end
>> end
> 
> Thanks a lot, Eric! This is the �d�oh!� solution I was looking for. :)

Shot, you should be aware that this works for your example given above, 
but not for the following:

   Block.new([1,12]).hash  # => 57
   Block.new([12,1]).hash  # => 23

If this is a problem, you have to change the implementation to

   class Block
     def hash
       sort.hash
     end
   end

Regards,
Pit