anchor.diff:  
      Example:
      ```
  -   > (check [(a number)] \
  +   > (check [(number a)] \
      .   (= a a))
  -   . 
  +   .
      (= a a) passed 100 tests.
      nil
  -   > (check [(a number)] \
  +   > (check [(number a)] \
      .   (= a (+ 1 a)))
  -   . 
  +   .
      (= a (+ 1 a)) falsified after 1 iteration(s)
      falsifying set of values:
        the number, a, had the value 3867638440
  
positive.code:                   (print! (.. ,(pretty prop) " passed 100 tests."))))))]
      `(let* ,(map generate-binding bindings)
         ,@(map generate-body props))))
  
  
negative.code:    iteration. This library has the ability to generate random numbers, strings,
     symbols, booleans, keys and lists."
    (let* [(generate-binding (binding)
             (destructuring-bind [(?type ?name) binding]
               `(,name (random-of ,(symbol->string type)))))
           (generate-regenerator (binding)
             (destructuring-bind [(?type ?name) binding]
               `(set! ,name (random-of ,(symbol->string type)))))
           (make-printing (binding)
             (destructuring-bind [(?type ?name) binding]
               `(print! (.. ,(.. "  the " (symbol->string type) ", "
                                 (symbol->string name) ", had the value ") (pretty ,name)))))
           (generate-body (prop)
  