sparse pattern query does not allow nested spare terms. #2972
Description
The sparse queries are used for the cheminformatics git repo. They consist of an unordered link holding the query pattern, and a glob to soak up everything else. As currently implemented in pull reqs #2968 #2970 #2971 these kinds of patterns cannot be nested one inside another. The fix to allow nesting is not hard: just do the same thing that the unordered link code does to push-pop the state onto a stack.
Fixing this seems like a low priority for now, I can't imagine what it would be used for ...