If more than one is valid (which I expect to be the usual state) then a random one of them is chosen.This is just freaking brilliant! I'd love to see what y'all come up with with these. I'll be trying to think of some suggestions but I'm a little lost in semantics on some of this.
Also, a question, what determines priority if you have overlapping qualifications for renaming on a given portion? For example, if my civ prefix qualifies for two adjusted 'names', which one gets the spotlight?
Check the Modder's Documentation thread for an expression system tutorial.