Philosophical coding question. In #Racket (as with other #Scheme-based languages) it's common for procedures to return #f (false) to indicate failure. So the following one-liner is occasionally useful for simplifying code that deals with the output of such procedures:
(define (opt-map proc arg [default #f])
(if arg (proc arg) default))
I think the real answer is "returning #f on error is and always has been a hack, compared to using a proper optional type"
"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko