[DAS2] feature group assembly; proposals for simplification

[Andrew Dalke]

Me [Andrew]:
> I've been working on a writeback server.  It will verify that the
> feature groups have no cycles, that if X is a parent to Y then Y
> is a part of X, and that all groups has a single root.
>
> I'm having a hard time with that, and harder than I expected.

I listed three alternatives and am hoping for feedback by email
rather than waiting another 10 days for the next phone conference.
They are:

   FEATURE elements add a "root" attribute pointing to the top-level 
feature
      for the feature group

   FEATURE elements must be listed in top-down order

   Features in the same feature group are inside a new element, as in
    <FEATURE_GROUP>
       <FEATURE ... />
       <FEATURE ... />
       <FEATURE ... />
    </FEATURE_GROUP>

Or, someone can show me a simple O(n) algorithm for building up the
feature group such that complete groups can be processed before
reaching the end of the feature data set.

Any comments?

					Andrew
					dalke at dalkescientific.com