What's the equivalent of Clojure's iterate function in Racket

Question

I'm playing with Racket today, and trying to produce an indefinite sequence of numbers based on multiple applications of the same function.

In Clojure I'd use the iterate function for this, but I'm not sure what would be the equivalent in Racket.

Answer 1

SRFI 41 ((require srfi/41)) provides stream-iterate directly.

You can use Óscar's examples and substitute stream-iterate wherever you see iterate, without having to define your own iterate. In addition, you can simulate Clojure's parameter destructuring using match-lambda:

(require srfi/41)
(define fib
  (stream-map first
              (stream-iterate (match-lambda
                                ((list a b)
                                 (list b (+ a b))))
                              '(0 1))))
(stream->list 10 fib)  ; => (0 1 1 2 3 5 8 13 21 34)