From: Robert Klemme <bob.news@...>
Date: 2005-11-16T23:42:17+09:00
Subject: Re: static variable; behaviour in ruby?

Hugh Sasse wrote:
> Any idea how to create or simulate a static variable in ruby?

I completely agree to Brian's comment.

> I want to create a variable to hold state between calls of a method,
> but have the state disappear when the method goes out of scope.
> I could create it in some external object but then I'd need to query
> the scoping rules, and know where i was.

I'm not sure I understand you correctly here.  Why don't you just create
an instance that holds this state plus whatever is needed and implement
your behavior in a method of that class?  You can control the number of
scopes by the nuber of created instances.

Also, IMHO Pit has a valid point with his remark about a contradiction.

> I'm trying to do an instance_eval on a string containing a method
>    such as do_this x,y,z {block}
> and I want to evaluate the block, or not, as a function of some
> state against which x,y,z are compared.  The code will be called
> several times, but I only want the state intialized the first time
> the scope
> is entered.
>
> And, just to make matters worse, there could be several independent
> calls to this method within the scope, each with its own separate
> state.
>
> Maybe there's another way to do this?

Did you consider using a Thread local stack for this (as I conclude from
your latest posting nesting is possible)?

Kind regards

    robert