From: Ken Bloom <kbloom@...>
Date: 2008-11-27T11:05:19+09:00
Subject: Re: How to use a passing argument(returned argument)?

On Tue, 25 Nov 2008 23:38:02 -0500, Einar Magn炭s Boson wrote:
> 
> I did not know this, google filled me in and this might be relevant to
> the original question:
> http://onestepback.org/index.cgi/Tech/Ruby/RubyBindings.rdoc/style/print
> 
> They end up with this:
> 
>    def swap(aref, bref)
>    aref.value, bref.value = bref.value, aref.value end
> 
>    a = 22
>    b = 33
>    swap(ref{:a}, ref{:b})
>    p a                       # => 33
>    p b                       # => 22
> 
> Pretty neat, if that's something you wanna do.

That rocks. Thanks for sharing. I thought that this kind of functionality 
would require syntax built into the language.

> Makes me wonder though:
> when I first saw this (5 minutes ago) I thought you might be able to do
> 
> a = 0
> 
> def set10(aArg_name,  bind=binding)
> eval("#{aArg_name} = 10", bind)
> end
> 
> set10('a')
> 
> p a
> 
> 
> but that doesn't work, in what context and when are default-values
> evaluated? my guess is that they get the same closure as the method body
> and are evaluated on call, is that correct?

Yeah. I'd love to have a Binding.of_caller or something like that, but 
have had no such luck. (Ok. It's an add-on in 1.8, but I'm curious about 
1.9)

-- 
Chanoch (Ken) Bloom. PhD candidate. Linguistic Cognition Laboratory.
Department of Computer Science. Illinois Institute of Technology.
http://www.iit.edu/~kbloom1/