From: Christoph <chr_news@...>
Date: 2003-09-25T00:56:22+09:00
Subject: Re: Hashes as keys

"Eugene Scripnik" wrote:
...
> Yes, you are right. This was just a fast dirty example of redefining 
> #hash method. BTW, you have to use pair[0].hash instead of pair[0] and 
> pair[1].hash similiarly. And think about collisions that your hash 
> method will generate, I think it is too simple.

Your probably right but if you really want a good and fast hash 
method you have to write this as an extension  anyway and 
experiment  a lot  - here is a random (probably over-complicated
and not necessarily good) variant
    
      
    def hash
        _h =  length * (length +43)  
        __h  =  1 << 31 - _h  >> 6
        each {|k,v|
            _h   +=  k.hsh^(v.hsh<< 2)
            __h  ^=  (k.hsh << 3) + v.hsh + k.hsh
        }
        _h  + __h +  _h ^__h
     end


/Christoph