On Fri, 5 Oct 2001, David Corbin wrote:
> Although it is in the manual, I'm still kind of flabergasted (though
> grateful) to find out that while processing a list A:!B is different from
> !B:A (at least that's the way I read the manual).
Correct. Colon is a list separator, not a boolean operator.
A:!B actually means "A or not B" (sort of)
!B:A actually means "not B and A" (sort of)
The second may seem silly, because if it's A it is "obviously" not B.
However, wild cards and address masks make this form useful. Consider
!x.y.z : *.y.z
for example.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
