Daan wrote (snipped)
I am flattered but I still view GIO as an *experiment* to get a feel of how a medium-level GUI API should look like, so it is not nearly a competitor to a real library. Well OK. In that case I think HTk *does* qualify as a real library. It has been around for several years, is pretty stable, and can be used to write fairly complex GUI interfaces. Its web-page, by the way, is http://www.informatik.uni-bremen.de/htk
However it is interesting that the look-and-feel of HTk and GUI are similar. This suggests that the general ideas of both are right. I'm not going to argue the details of syntax such as whether # should be in there or not. The main difference is that HTk uses events while GIO uses callbacks. In the HTk example I gave, buttonClicked is an event.