On Wed, 17 Aug 2005, Alan Barrett wrote:
> I'd prefer to see keywords like "required", "optional" and "prohibited",
> rather than "yes" and "no".

Actually, the prohibited/optional/required status could just be implied
by the numeric ranges, but then you'd have to use "0 means 0", not "0
means infinity".  For example, "upper: 0" could mean "prohibited";
"upper: 1-*" could mean "1 or more required"; "upper: 1-3" could mean
"at least 1, but no more than 3"; "upper: 0-*" could mean "any number,
zero or more".

--apb (Alan Barrett)