anchor.diff:                            ,ctr " iteration(s).\n Falsifying set of values:\n"
                             ,@(map make-printing bindings))))
                       (inc! ,ctr)))
  -                (when ,ok
  -                  (print! (.. ,(pretty prop) " passed 100 tests."))))))]
  +                )))]
       `(let* ,(map generate-binding bindings)
          ,@(map generate-body props))))
  
positive.code:   (struct :tag "symbol" :contents (random-string)))
  
  (defun random-type () :hidden
    (let* [(types '("symbol" "boolean" "number" "string" "key"
                    "list"))]
      (nth types (random 1 (# types)))))
  
  (defun -random-type () :hidden
  
negative.code:     ["number" (random-number)]
      ["symbol" (random-symbol)]
      ["key" (random-string)]
      ["list" (random-list)]
      ["any" (random-of (random-type))]))
  
  (defun random-list () :hidden
    (let* [(length (random 1 2))]
  