I track order just for identify unordered element set (like elements defined inside 'all'
So I can't think of a situation where tracking the order of the elements is important inside the parse_om function. Even if it is implemented, it won't be able to do many things than complaining that the elements are not in the right order, so I can't parse it.
Well parse_om and build_om are also not good names for the above functions. As I posted in the yesterday mail they are doing convert one OM to some other OMformat
build_om converts XML(axiom) --> schema type objects
parse_om converts schema type objects-> XML(axiom)
I may have to replace these functions very soon (at least their names for now).