Racket has a documentation system called Scribble.
Which is actually one of the most interesting features of Racket -- that it lets you implement a `#lang scribble` which does not even use s-expression syntax, but you still have the full power of Racket if you need it.
The default `#lang racket` is a wonderful modern lisp, and you can use Racket as "only" that. But Racket is also a system for making languages.
