From: Stefano Crocco <stefano.crocco@...>
Date: 2007-05-06T20:21:53+09:00
Subject: Re: dynamically named variables or Constants

Alle domenica 6 maggio 2007, Tom V. ha scritto:
> Hi,
>
> for each user I need to create and call
> a dynamically named _GLOBAL_ variable (or Constant)
> labeled with the user name.
> To make it clear what I mean:
>
> # begin "Ruby Pseudocode"
>    user_name = "tom"
>    $#{user_name}_dyn_var = "/path/to/nirvana"
> # end "Ruby Pseudocode"
>
> Is there a way to do that?
> How would I call that new variable '$#{user_name}_dyn_var' ?
> I tried "Module::const_set":
>
> # begin Ruby
>    constant_name = "#{user_name.upcase}_VAR"
>    constant = self::class::const_set(constant_name, "/path/to/nirvana")
> # end Ruby
>
> but couldn't find a way to call "#{user_name.upcase}_VAR".
>
> you may ask why I either need a global var or a Constant:
> I am using the "live_tree" plugin
> from http://www.epiphyte.ca/code/live_tree.html
> to create a file system browser.
> As far as I can tell,
> the plugin requires either a global var or a Constant
> to initialize the file system model.
>
> If someone has tried this plugin before
> and found another solution, let me know.
> The author is not responding to my mails.
>
> Thanks for your input,
> Tom.

I'm not sure about what you mean when saying 'a way to 
call "#{user_name.upcase}_VAR". If you mean how to get the value of the 
constant, then you can use const_get, which works like const_set:

self.class.const_get( constant_name)
=> "/path/to/nirvana"

I hope this helps

Stefano