Re: questions about attributes and compound types...

Quincey Koziol wrote:

Hi John,

We've got a question: is there a way to attach an attribute to a
member of a compound type dataset. That is, if I have a dataset of
something that is a compound type, can I attach at attribute not to
the whole dataset, but just to one member of the compound type?
  Hmm, we've had a couple of requests for similar features, but you can't
do this currently.  What's the motivation for this?

I think I will let John answer this part...
the motivation comes from creating a unifying model with the opendap data model.

opendap structures contain "first class" variables that can have attributes.
   Hmm, interesting...

however, if thats not feasible, i can do a workaround where opendap structures become groups instead.
   Well, it definitely isn't currently supported.  Should I open an issue for
this in our tracker so we consider in the future?  I'm just a bit concerned
about supporting the full generality of it, like attributes on parts of array
datatypes or nested compound datatypes, etc.

yes, i think its worth considering in the future. this would make structure members first class citizens. the attributes would apply to the structure member as a whole, not individual array elements, just as for an array dataset.

as i said, the motivation comes from opendap structures. ironically, i suspect that it was at least in part motivated there by mapping hdf (4/5?) into opendap, where they decided to map "groups" into "structures". so we can just undo that and map opendap structures to groups when needed.