Caleb Tennis wrote:
> When using a singleton class (one that includes Singleton, not an  
> eigenclass), can anyone think of any advantage/disadvantage to using  
> class variables over instance variables (or visa versa) to access  data 
> in the class?

In answer to this question and the one about thread-specific singletons: 
another approach to consider is using a dependency injection framework. 
They all support singleton services, and at least some of them support 
services that return one unique object per thread.

One disadvantage to using class variables (@@var) is that they are (in 
the current ruby) per-hierarchy, not per class. So a subclass will share 
the value of @@var. This is, I've heard, going to change in ruby 2.0.

-- 
        vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407