Technically, the Racket version is using a separate lexer and parser library, it's just that Racket erases the line between what is a library and what is a lang

Technically, the Racket version is using a separate lexer and parser library, it's just that Racket erases the line between what is a library and what is a language when it comes to lexers and parsers. One could either say this is a Racket program that uses the Brag library, or a Brag program (though the latter is preferred in the Racket ecosystem).