anchor.diff:    (list 'integer 0 length))
   
   (defun hamming (x y)
  -  "Calculates Hamming distance between two given strings, they have to be
  -of the same length."
  +  "Calculate Hamming distance between two given strings X and Y, they have
  +to be of the same length."
     (declare (type (simple-array character) x y)
              (inline length)
              (optimize (safety 0) (speed 3) (space 3)))
  
positive.code:           (length y))))
  
  (defun jaccard (x y)
    "Calculates Jaccard similarity coefficient for two strings. Returned value
  is in range from 0 (no similarity) to 1 (exact match)."
    (declare (type (simple-array character) x y)
             (optimize (safety 0) (speed 3) (space 3)))
    (let ((x (string-to-set x))
  
negative.code:       (rotatef v0 v1))))
  
  (defun damerau-levenshtein (x y)
    "Calculate Damerau-Levenshtein distance between two given strings X and
  Y."
    (declare (type (simple-array character) x y)
             (inline length)
             (optimize (safety 0) (speed 3) (space 3)))
  