From: Stefano Crocco <stefano.crocco@...>
Date: 2007-09-18T15:10:35+09:00
Subject: Re: how to use tuple as hash key

Alle lunedì 17 settembre 2007, SpringFlowers AutumnMoon ha scritto:
> h2 = {}
> a = [0, 0]
>
> for i in 1..2
>   for j in 1..2
>     a[0] = i
>     a[1] = j
>     h2[a] = "ha"
>   end
> end
>
> p h2
>
> =======================
> will produce:
>
>...
> {[2, 2]=>"ha", [2, 2]=>"ha", [2, 2]=>"ha", [2, 2]=>"ha"}

This happens because you don't call h2.rehash after modifying the array you 
use as key (look at the ri documentation for Hash#rehash for a longer 
explaination). If you insert the line 

  h2.rehash

after 

  h2[a] = "ha"

you'll get the expected behaviour.

Stefano