[DAS2] having problems with feature xml from test server

[Helt,Gregg]

I'm still having some problems on the client side with parsing DAS/2
feature xml from the biopackages server.  Here's my test query: 
 
http://das.biopackages.net/das/genome/chado/chado-Hsa-17/feature?overlap
s=chr21/22100000:22500000;type=SO:mRNA 
 
The main problem I'm having is really due to ambiguity in the spec.  In
the feature xml response, the child features of an mRNA feature don't
have a "parent" attribute giving the id of the parent feature.  The mRNA
feature does have <PART> sub-elements giving ids of its child features.
But unless we specify that if there is a child/parent relationship both
<PART> element in the parent and "parent" attribute in the child are
required, there's no way of knowing until you've reached the end of the
document whether a particular feature is a "root" feature, or whether it
has a parent.  And therefore you can't really implement a useful
streaming parser.  This came up before at the weekly meeting, but it
hasn't been added to the spec change database yet - I'll add later
today.
 
            thanks,
            gregg