I agree that it is the Right Thing to do. If everyone else agrees it is the
Right Thing to do I will be very happy. If 10% agrees and the other 90%
don't know what we are on about, we need to make sure they can't Go Wrong :-)
>
>The first case is often used to mean a known, empty value; the second
>to mean "not known" or "not applicable".
>
>Concrete example: I'm a rock climber, and I keep a record of all my
>climbing in XML format. Climbs are defined as
How exciting - I used to be (not a very good one).
[...]
>
>climbs.xml> <climb grade="VD" stars="" style="2"
>climbs.xml> with="&p-hkm;">Difficult Crack</climb>
>
>Here, the lack of stars is explicit - it's not a high-quality climb.
>Whereas
>
>climbs.xml> <climb grade="D" with="&p-ejk;, &p-dmj;"
>climbs.xml> style="l">King's Chimney</climb>
>
>is a climb in a part of Britain where the star system isn't used, and
>so I omitted the attribute - even though it probably deserves a star
>or two.
Not according to MacInnes' star system; he gives it zero stars :-).
Seriously, if we adopt this system then we should make every effort to
promote it. One difficult area is in editors - how do you signal the
difference between
"" and null when entering a value in a box? You either have to get them to
input NULL (yukk) or add another button for "IMPLIED" (Ugh).
I'd like some other expert opinion on this. It's a tricky area if we get it
wrong.
P.
Peter Murray-Rust, Director Virtual School of Molecular Sciences, domestic
net connection
VSMS http://www.nottingham.ac.uk/vsms, Virtual Hyperglossary
http://www.venus.co.uk/vhg