From: Robert Klemme <bob.news@...>
Date: 2005-10-15T01:56:55+09:00
Subject: Re: Odd behaviour concerning procs.

Christophe Poucet wrote:
> Hello,
>
> I've noticed the following behaviour and I'm not certain if this is
> expected behaviour, however from the point of view of any other
> language, it certainly seems odd.
>
> Assume there is no constant with the name 'X' defined anywhere.
>
>   X => NameError: uninitialized constant X
>   proc{|X| true}.call(15) => true
>   X => 15
>   proc{|X| true}.call(15) # true, warning: already initialized
> constant X
>
> I would presume that the X would be localized to the proc.  I know
> that for normal variables, the variable in the calling scope is only
> changed if it already exists, but in this case, the constant X does
> not even exist. (And when it does exist, is it really preferred
> behaviour that a proc will change a constant?)

Basically the part between || leads to a normal assignment.  So this
behavior is pretty much in line with other behavior (i.e. for local vars).
I guess the difference comes from the fact that lookup for constants is
done a bit differently.  This allows to do what you cannot do with a local
var.  It's odd, yes.

Kind regards

    robert