On Fri, 21 Dec 2007, Quentin Garnier wrote:
> > Yes, I know it currently fails, but I'd like "no nonexistent" to
> > silently do nothing.  "no impossible", on the other hand, should
> > probably be an error, where "impossible" is something that doesn't have
> > a "device" or "attach" or other relevant declaration.
> 
> Well, how is a device foo disappearing from conf/files any different
> from defopt bar disappearing from the same file?

I don't really know what you mean, so let me try to clarify what I mean.

Given

	MYCONFIG:
		include GENERIC
		no foo
		no bar
		no baz

	GENERIC:
		machine i386
		isa0 at mainbus0
		foo0 at isa?
		# bar and baz not mentioned at all

	files.i386:
		device isa
		device foo
		attach foo at isa
		device bar
		attach bar at isa
		# baz not mentioned at all

then I'd like the "no foo" in MYCONFIG to undo the "foo0 at isa?"  that
was defined in GENERIC; I'd like the "no bar" to silently do nothing
(because bar is a plausible device, even though it wasn't used in
GENERIC); and I'd like "no baz" to be an error (because baz is not a
plausible device).

--apb (Alan Barrett)