Sure, I already groked that you was meaning the postpostpostpostpostnextSTEP environment for the whateverapp store (don't read this in a mocking tone on your efforts in this system, it isn't intended at all). Well this really is enlightening about Mac OS, thank you. Under these constrainments, though, it seems to me you'll have to reinvent mxterm or rxvt with tabs. Or adding, like, a terminal mux in the program. And this is a lot more than just porting st to Mac OS X. Good luck!
-- Teodoro Santoni
