That language is OMeta. There are several implementations; the latest JavaScript compiler is just a few hundred lines. http://www.tinlizzie.org/ometa/ http://w

That language is OMeta. There are several implementations; the latest JavaScript compiler is just a few hundred lines. http://www.tinlizzie.org/ometa/ http://www.tinlizzie.org/ometa/ The compiler is self-hosting; much of that JS code is actually compiled from OMeta source. For another example, the Common Lisp version includes fewer than 200 lines of OMeta source and fewer than 300 lines of Lisp source. OMeta was a very eye-opening language for me because of the great expressiveness it gets from its simple but novel approach. (I've written code in Haskell, Prolog, Scheme, OCaml, and plenty of other languages, but OMeta is not like any of them.) If you are interesting in programming languages and/or parsing, Warth's thesis is a great read.