Forth is a computer programming language based on Reverse Polish Notation, e.g. in arithmetics like HP calculators:
1 2 + 3 * 4 / ~ [expr ((1+2)*3)/4)]
FORTH in tcl anyone?
Chuck Moore created FORTH. An interesting article about FORTH appeared in Byte magazine [L1 ] .
Related to this is 1% the code a shocking paper by Chuck Moore.
Tutorials
Often over the years, FORTH and Tcl have been compared because of the mindset in both to write lots of procs/words to do one's work.