Tkinter[0] was apparently released in 1994, so mildly interesting he didn't say "Tcl tends to get ported to weird places like other programming languages."
My next question to myself was what hardware was running Tcl in c.1997 Cisco equipment? What porting effort was required? I understand there was some proprietary feature work for Cisco IOS, but I don't know what architectural work was required.
And which gives us tailcalls and coroutines.