If it's going to be that tricky, it might be better to add ISO support later.
I mean, there aren't even that many PCBs that support ISO (some of the newer asian ones like GON and red scarf do though) and it's not as popular for custom PCB design as ANSI.
I think the following shows how hard it was for me to grasp how it works (or doesn't)
["","",{h:2},""],
["",""],
["","",{h:2},""],
["",""],
[{y:0.5}],
["","",{h:2},""],
["",""],
["",""],
["","",{h:2,y:-1},""],
[{y:2.5}],
["",""],
["","",{h:2,y:-1},""],
["",""],
["","",{h:2,y:-1},""]
The first two work but the third does not. Though this may just be my own complaints as an end-user, I have no programming experience so maybe I'm missing something.
Still, it might be prudent to contact the athour to make sure that only "legal" code be supported by your tool as well.