Okay, happy to admit when I'm not fully informed, and this is one of those times. I have interacted with TCL/TK and have made small programs with it, but I have not used TCL directly in the past. In fact, did not even realize TCL was a full language. When I read this article, given my background with TCL/TK, I understood it to be a web framework using a weird desktop GUI... which would be quite odd.