Confused by recurring-duration

I find the recurringDuration datatype a little confusing.  What exactly
is the value space?  Specifically, is the value space of
recurringDuration different from the value space of timeInstant? If I
have a datatype like recurringDay, which is derived from
recurringDuration, then presumably any value in the value-space of
recurringDay needs also to be in the value-space of recurringDuration. 
It's not obvious to me how to define the value space of
recurringDuration to make this the case.  It seems like the value space
is the same as a timeInstant except that some fields can optionally be
null/missing. But if that's the case, then not all values in the
recurringDuration value space can be represented by literals in the
lexical space. 

I'm trying to figure out how one might add a recurring-duration datatype
and associated operations to XPath. timeDuration makes perfect sense to
me, as do all the datatypes derived from recurringDuration, but
recurringDuration itself feels rather artificial.

Received on Wednesday, 13 September 2000 01:54:00 UTC