>> I've been working on some enhancements to config(8).

>> I've added a new keyword to the config(8) file grammar - "no" -
>> which may be used in the follow ways: [...]

This looks to me like something that config has needed for a long time.
I'm glad to see it going in.

Now all we need is "no device foo at bar" and "no device foo" lines,
but yes, those would be more difficult.  Start with the easy parts. :-)

("no device foo" would be equivalent to "no device foo at bar" for all
possible values of bar.  It might be nice to have an optional "and
children" clause which silently deletes anything orphaned by the
removal, for things like "no device isa and children" to easily build a
kernel without ISA support.)

> how is putting a "no " in front of the line substantially different
> from  putting a "#" in front of it?

Because a commented line doesn't cancel a previous line (probably
brought in from an included file).

That is,

>> I.e, the sequence
>> 	pseudo-device foo
>> 	no pseudo-device foo
>> should result in the same kernel compile directory as if neither
>> line appeared in the configuration file.

whereas

	pseudo-device foo
	#pseudo-device foo

is equivalent to the version without the comment.

/~\ The ASCII				der Mouse
\ / Ribbon Campaign
 X  Against HTML	       mouse@rodents.montreal.qc.ca
/ \ Email!	     7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B