20:34 <winny> sometimes I'm using a for-form in a way that lends to filtering out iterations based on a criteria - using a `#:when when-expr` optional subform. But then it becomes apparent the work done to test if the iteration should happen in `when-expr` is the same work I like to use in the for-form's body. For example: (for/list ([i (in-lines)] #:when (expensive-transform i)) (expensive-transform i)) -

20:34 <winny> any way to reuse the computation done in the `when-expr` in the body-expr?

21:09 <newschemer> I'm trying to use the random-sample function, per https://docs.racket-lang.org/reference/generic-numbers.html#%28def._%28%28lib._racket%2Frandom..rkt%29._random-sample%29%29, with racket 8.3 CS, but I get an unbound identifier error at the repl. What am I doing wrong?

21:09 <rudybot> https://teensy.info/S24p9dCKN6

21:18 <newschemer> ah, I needed to (require racket/random)

21:18 <newschemer> solved, sorry to bother