Slug generator pasted by C-Keen on Fri Jan 13 11:02:40 2017

(use srfi-1)

(define (slug len)
  (define chars
    "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890")
  (list->string
   (map
    (lambda _
      (string-ref chars (random (string-length chars))))
    (iota len))))

slightly more compact version added by Kooda on Fri Jan 13 11:25:23 2017

(use srfi-13)

(define chars
  "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ123456789")
(define slug
  (cut string-tabulate
       (lambda (_) (string-ref chars (random (string-length chars))))
       <>))