Qi YACC
Qi YACC is an untyped compiler-compiler based on a top-down recursive descent parsing strategy. It is derived from the TDPL (top-down parsing language) and is the basis for much of the inbuilt parsing in Qi. Qi YACC takes Backus–Naur Form code directly as a pseudo-code:
becomes
(defccThe following is a Qi-YACC program that parenthesises any input occurring between { ... }s.
(2-) (defccQi-YACC is more extensively discussed on the home site (see External Links).
Read more about this topic: Qi (programming Language)