I am fine with a representational XML which depicts the contents of the tree with the data for each node --- my idea is I would parse the XML and re-create the structure inside my program (which is pretty much what I had in mind for supporting BlockSCAD).
Ah, ok, so do I understand correctly you would sort of like a visual preprocessor for programmatic model data?
And specifically ”whatever xml”, not, say STEP, or , openscad code, python code (via using cadquery) or anything like that?
Do you know your final output format?