how is putting a "no " in front of the line substantially different from 
putting a "#" in front of it? does this really warrant a change in the 
grammar?

isildur

On Tue, 4 Jun 2002, Luke Mewburn wrote:

> 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:
> 	no pseudo-device foo
> 	no options foo[,bar[,...]]
> 	no mkoptions foo
> 	no file-system foo
> 
> These are only valid if an appropriate matching config entry has
> already been used.
> 
> If a declaration would have resulted in extra files being brought
> in (e.g "pseudo-device bpf" pulls in bpf.o and bpf_filter.o, with the
> latter potentially shared with ppp) and the "no" equivalent follows,
> then the extra files won't be brought in if they're now not necessary.
> 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.
> 
> The purpose of this is to allow you to easily create custom config
> files by including "GENERIC" and then disabling stuff you're not
> interested in.
> 
> Unless someone suggests (and hopefully implements :) a better way to
> solve this problem, I intend to commit the work I have done so far in
> the next day or two.
> 
> 
> I've also started on "no device foo at bar", but that's a lot trickier
> than the others to get "right".
> 
> Comments?
> 
> Luke.
> 
> -- 
> Luke Mewburn  <lukem@wasabisystems.com>  http://www.wasabisystems.com
> Luke Mewburn     <lukem@netbsd.org>      http://www.netbsd.org
> Wasabi Systems - NetBSD hackers for hire
> NetBSD - the world's most portable UNIX-like operating system
>