defsystem: when to use :uses-definitions-from dependencies?

[dmitchell@trc.amoco.com (Donald H. Mitchell)]

I understand the need to use (:uses-definitions-from foo) 
or (:in-order-to (:compile :load) (:load foo)) when foo contains macros that the module
requires.  What dependencies should I use when foo contains 
CLOS class definitions? 
CLOS generic functions? (I'm assuming (:in-order-to (:load) (:load foo)))
CLOS methods? (I'm assuming (:in-order-to (:load) (:load foo)))

Are there any situations other than macros where I need (:uses-definitions-from foo)?

Slightly different question:

I've used (:uses-definitions-from foo-system) to show dependencies among systems; however,
compile system does not seem to check whether the system foo-system has been recompiled
when determining whether to compile the given module.  Is there a way to force this check
without having to use the force compile option on the call to compile system?

Don Mitchell			dmitchell@trc.amoco.com
Amoco Production Company	(918) 660-4270
Tulsa Research Center
P.O. Box 3385, Tulsa, OK 74102