but… why?

The scope of bindings introduced by define is the entire enclosing definition context. This is the same mechanism behind flexible mutually-recursive definitions: (define (compute) ... (define (even? x) ... (odd? x) ...) (define whatever ...) (define (odd? x) ... (even? x) ...) ... (define (double x) ... (double (sub1 x)) ...) ...)

Does racket have a null output port so I can make some functions that display output in a “debug” mode, but then do something like:

(parameterize ([current-output-port (null-output-port)]) (my-function)) ?

nvm.. just found open-output-nowhere (odd name)