I have been watching the animated discussion on the revived SDD list and it is tood to see... too busy to comment, but still interested, and useful things are being said by others... :)

Existing data structures allow 2-level hierarchies e.g. #1. Leaf shape/ 1. ovate/ 2. elliptic/ #2. Flower colour/ 1. blue/ 2. red/

Is that really two levels of character is is it only one with a state attribure?

Also, in our new model we also want to show more than just presence or absence of a state. Don't we want to show if it is present/rarely present/present by misinterpretation/rarely present by misisnterpretation, etc., and my favourites yet to be implemented as a character stae attribute: definitely absent, absent by misinterpretation, unknown, unscored

I'm simply suggesting allowing n levels:

<Leaves> <shape> <ovate> <elliptic> <Flowers> <colour> <blue> <red>

That is where we want to get to do, but echoing Bob's words, what we are after is the structure that allows us to get to that, giving people all the appearance of freedom to do what they like but not actually doing it and imposing a schematic straight jacket on the data. A schema for the data structure rather than the descriptive data itself. Like all freedoms, the descriptive data one too must be an illusion or we wil miss out on on all the creative potential that it offers as the free spirits among us do theri own thing. But that is another discussion... :)

There has been a lot of talk about the feature/value paradigm and how this might be made to represent a biological description and even nested features in such descriptions...

At the recent TDWG meeting Richard Pankhurst described something like a feature/character/value paradigm and at the time I made a note that this was probalably worth considering in more detail, but so far have not had the time.

It probably would mean something like:

<feature name="leaf" charecter="margin" value="serrate"/> or some equivalent using XML entities rather than attributes.

Is there any merit in this approach above using a feature that is say "leaf margin" and another that is say "leaf tip" and yet another that is say "leaf base"? It would seem to give some structure to the character set data.

On the surface it would also allow easy generation of more readable descriptions without excessive text processing:

Leaf outline ovate, margin serrate, tip acute, base attenuate, etc.

as opposed to:

Leaf outline ovate, leaf margin serrate, leaf tip acute, leaf base attenuate, leaf... etc.

Has anyone else considered this approach?

jim