anchor.diff:  (defun hex (n)
     (format t "~X" n)
     (values))
  +
  +
  +(defun concatenate-integers (&rest integers)
  +  "Concatenate each integer in `integers` and return a big ol' integer result."
  +  (values (parse-integer
  +            (format nil "~{~D~}" integers))))
  +
  +
  +(defun pandigitalp (integer &key (start 1) (end 9))
  +  "Return whether `integer` is `start` to `end` (inclusive) pandigital.
  +  
  +  Examples:
  +
  +    (pandigitalp 123)     ; => nil
  +    (pandigitalp 123 1 3) ; => t
  +    (pandigitalp 123 0 3) ; => nil
  +
  +  "
  +  (equal (range start (1+ end))
  +         (sort (digits integer) #'<)))
  +
  +
  +(defun-inline digits< (n digits)
  +  "Return whether `n` has fewer than `digits` digits."
  +  (< (abs n) (expt 10 (1- digits))))
  +
  +(defun-inline digits<= (n digits)
  +  "Return whether `n` has `digits` or fewer digits."
  +  (< (abs n) (expt 10 digits)))
   
   
   ;;;; Problems -----------------------------------------------------------------
  
positive.code:         (incf count))
        (while (< count 11)))))
  
  ;;;; Tests --------------------------------------------------------------------
  (def-suite :euler)
  (in-suite :euler)
  
negative.code: (test p35 (is (= 55 (problem-35))))
  (test p36 (is (= 872187 (problem-36))))
  (test p37 (is (= 748317 (problem-37))))
  (test p38 (is (= 932718654 (problem-38))))
  
  
  ;; (run! :euler)
  