isort.rkt

#lang racket

(define (isort cs)
  (define (insert x xs)
    (cond [(empty? xs) (list x)]
          [else (if (< x (first xs))
                    (cons x xs)
                    (cons (first xs) (insert x (rest xs))))]))
  (cond [(empty? cs) cs]
        [else (insert (first cs) (isort (rest cs)))]))

(module+ test
  (require rackunit)
  (check-equal? (isort '(4 6 7 3 45 9 7 5)) '(3 4 5 6 7 7 9 45)))