Ada is a computer language developed originally for DOD contracts. It has rather a lot of features.
During early development, the language was called Green. It is now named after Ada Lovelace
GNAT, which is freely-available and distributed as part of Gcc, is one of the major Ada implementations. AdaCore sells a range of products based on GNAT and also provides a free version. See Debian policy for Ada for more information.
In short:
Latest release: tash-8.6-0-20110925.zip {date 2011-09-25 size 263.2 kB} License: GPL with "Linking Exception" (Confirmed by Simon Wright)
Visual Ada Developer is a Tcl/Tk-oriented Ada-95 GUI builder. The GPLed version is here Leonid Dulman updated in mid-2006 includes a "Tcl script generator", and appears to be compatible with both 8.5 and 8.6. His Ada Developer Studio also interfaces to Qt, which has a very slender Tcl connection.