> What's the phylosophical difference between these for singletons?
IMHO, from a conceptual point of view, none of these selector is
appropriate for a Singleton. While they provide a global access point,
both #current and #default imply there might be some other instances
(not current or not default) of the same class.
Singleton's intent is: "Ensure a class only has one instance, and
provide a global point of access to it.".
IIRC, there is some discussion about this topic in this nice book:
http://www.amazon.com/Design-Patterns-Smalltalk-Companion-Software/dp/0201184621/sr=8-1/qid=1158603467/ref=sr_1_1/102-4769576-8613767?ie=UTF8&s=booksI prefer to use #instance in my own code.
Best regards,
Dan