;This code made by: Peotr Wojciec

(defun eucliddist (row1 row2 &optional (fss (thecols)) (tbl (thetable)))
  (dist (mapcar (selectcols fss) (row-cells row1) (row-cells row2) (table-cols tbl))))

(defun euclidtest (n m) (eucliddist (nth n (therows)) (nth m (therows))))

(defun dist (lst)
  (let ((r^2 0))
    (dolist (x lst (sqrt r^2))
      (incf r^2 (* x x)))))

(defun selectcols (fss)
  (lambda (el1 el2 coll)
    (if (memberp coll fss)
      (coldist el1 el2 coll)
      0)))

(defmethod coldist (el1 el2 (coll sym))
  (cond ((col-goalp coll) 0)
         ((unknownp el1) 0)
         ((unknownp el2) 0)
         ((eql el1 el2) 0)
         (t 1)))

(defmethod coldist (el1 el2 (coll num))
  (cond ((col-goalp coll) 0)
         ((unknownp el1) 0)
         ((unknownp el2) 0)
         (t (- (normalized el1 coll) (normalized  el2 coll)))))

(defun normalized (el coll)
  (/ (- el (num-min coll)) (- (num-max coll) (num-min coll))))

(defun unknownp (cell) (eql cell #\?))