(defun iterative-dichotomize (n tbl &key splitter)
   (labels ((trainer (tbl cautions egs)
             (id-trainer tbl :splitter splitter))
           (tester (tbl cautions model one)
             (cons (isa one tbl)
                   (id-tester one model))))
     (n-way n tbl
            :trainer  #'trainer
            :tester   #'tester)))

(defun id-tester (eg tree)
  (id-tester1 eg (node-kids tree)))

(defun id-tester1 (eg trees)
  (cond ((null trees) nil)
        ((node-p trees) (rest (node-key trees)))
        (t
         (let* ((tree (first trees))
                (pair (node-key tree))
                (kids (node-kids tree))
                (feature (first pair))
                (range   (rest pair)))
           (if kids
               (if (eql (nth feature eg) range)
                   (id-tester1 eg (node-kids tree))
                   (id-tester1 eg (rest trees)))
               range)))))

(defun id-trainer  (tbl &key  splitter (min 4) (condense #'table-majority-class))
  (make-node :key 'root :kids (id-trainer1 tbl  splitter min condense)))

(defun id-trainer1 (tbl splitter min condense)
  (let ((before (table-height tbl)))
    (if (< before min)
        (make-node :key   (cons 'then (funcall condense tbl)))
        (let* ((x        (cross-index tbl))
               (split    (funcall splitter x))
               (egs      (table-egs tbl))
               (names    (xindex-feature-names x)))
          (mapcar
           #'(lambda (range)
               (id-trainer2 range x egs split splitter min tbl before condense))
           (xindex-feature split x))))))

(defun id-trainer2 (range x egs split splitter min tbl before condense)
  (let (some)
    (dolist (eg egs)
      (if (eql range (nth split eg))
          (push eg some)))
    (if (< (1+ (length some)) before)
        (make-node :key (cons split range)
                   :kids (id-trainer1 (table-copy tbl some) splitter min condense))
        (make-node :key  (cons 'then (funcall condense tbl))))))