From: Adam Prescott <adam@...>
Date: 2011-12-06T01:34:39+09:00
Subject: Re: black magical hash element vivification

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On Mon, Dec 5, 2011 at 16:28, Chad Perrin <code@apotheon.net> wrote:

>    >> foo = Hash.new( Hash.new )
>    => {}
>    >> foo[3][2] = true
>    => true
>    >> foo
>    => {}
>

This is odd.


>    >> foo[3]
>    => {2=>true}
>    >> foo[2]
>    => {2=>true}
>

This isn't. Hash.new(Hash.new) != Hash.new { |h, k| h[k] = Hash.new }. The
left hand side uses the same object for each default access, hence f =
Hash.new([]); f[1] << 1; f[2].include?(1) == true. The right hand-side
behaves as you expect for this part.

   >> foo
>    => {}
>

Again, definitely odd! :)

foo.rehash didn't fix anything. Looks like a bug to me?

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