On Thu, 4 Jan 2001, Jeffrey Goldberg wrote:
> (!X or Y) and (!Z or W)
>
> I don't think that that can be done with ACLs, but I don't have a proof.
> (actually the more I think about it, the more I think it CAN be done with
> ACLs. But I'm not sure how.)
Like this:
deny X : !Y
accept !Z
accept W
Essentially, the existence of "deny" allows you to have a "vertical
AND", if you see what I mean. It's like Exim's lists:
local_domains = a : b : c
can be read as "a or b or c", but
local_domains = !a : b : c
is "not a and (b or c)". The negative changes the implicit conjunction.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
