From: "Thomas B." <tpreal@...>
Date: 2009-07-23T02:02:59+09:00
Subject: Re: Incorrect -0.0.hash - Ruby bug.

James Coglan wrote:
> 
> Is there a reason for this? Perhaps the inexact nature of Floats means 
> you
> ought not to use them as hash keys?

In my program it's very convenient to use float vectors as keys because 
I create a graph where points (vertices) are calculated numerically as 
cross points of lines and so on (that's why I get -0.0 from time to 
time). I round the floats to 8 decimal digits, and added a quick fix for 
the hash:

alias :hash_orig :hash
def hash
  eql?(0.0) ? 0.0.hash_orig : hash_orig
end

and it works like it should, so I think it was a good idea to use them 
as keys :)
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