streams in racket

Question

Can anyone help me better understand how to write a stream?

I understand that a stream is an infinite sequence of values and the way I have learned programming them

Answer 1

It looks like you were asking how to build your own custom streams with thunks, which others have already answered. Just in case, it's worth noting that Racket has a stream library built-in and most Racketeers would use that for streams.

Here's an example:

#lang racket
(require racket/stream)
(define reds (stream-cons "red" reds))
(define red-blues (stream-add-between reds "blue"))

;; show ten of them
(for ([i 10] [e (in-stream red-blues)])
  (displayln e))