[jarcane]

Racket had parser generators available. See for instance ragg, or is fork, the brag parser used in the Beautiful Racket book: https://docs.racket-lang.org/brag/index.html

The technique used in the book is to use brag to describe the grammar and generate a parser/tokenizer to s-expressions, and then you can either interpret it compile them directly, or use the Racket macro system itself to expand them into Racket.

And of course, Racket's macro system itself can do quite much without even a parser generator. The standard library even includes an example ALGOL 60 implementation done as Racket macros, and examples of C and Java can be found on the package server.