anchor.diff:  (defun \\ (xs ys)
     "The difference between XS and YS (non-associative.)
   
  -   Example:
  +   ### Example:
      ```
      > (\\ '(1 2 3) '(1 3 5 7))
      out = (2)
  
positive.code:   (assert-type! f function)
    (assert-type! ac function)
    (foldl ac z (map f xs)))
  
  ;; AUTOMATICALLY GENERATED
  ;; DO NOT EDIT please.
  
negative.code:               get-idx for gensym -or slice /=
                pretty print error tostring  -and
                unpack debug if # + - >= = ! with
                apply and progn .. *))
  (import base)
  (import lua/table)
  (import type (nil? list? empty? assert-type! exists? falsey? eq? type))
  