From: Jonas Delfs <jonas@...>
Date: 2002-03-27T23:49:09+09:00
Subject: Re: Hash.new(Hash.new) doesn't use Hash.new as default value

"ts" <decoux@moulon.inra.fr> skrev i en meddelelse
news:200203271416.g2REGPk06934@moulon.inra.fr...
> >>>>> "J" == Jonas Delfs <jonas@NOSPAMdelfs.dk> writes:
>
> J> If it's no bug, I think it's a bug in documentation. - and not a very
logic
> J> behavior.
>
>  No, it's not a bug nor a bug in the documentation.
>
>  What you must understand is that when you write
>
>   Hash.new(Hash.new)
>
>  is like
>
>   default_value = Hash.new
>   Hash.new(default_value)

Ohh. I think it's the fact that everything by default gets passed by
reference that have tricked me.
I can't force Ruby to .dup that object, can I?

>  With 1.7 you'll have the possibility to write
>
>  Hash.new { Hash.new }
>
>  and each times a key is not defined, ruby will evaluate the block, the
>  result of the block will be stored in the Hash and ruby will do what you
>  want.

Okay.

--
Mvh./Best Regards
Jonas Delfs, http://delfs.dk