;Deftests for chapter 4
(deftest justinChap4 ()
  (check ;open check
    (string-equal "Justin" (let ((str (copy-seq (concatenate 'string "dus" "tin")))) (setf (char str 0) #\j) str)) ; check for section 4.3
    (equal '("first" "2nd" "Last") (tokens "first 2nd Last" #'constituent 0)) ;check for figure 4.2
  ); close check
) ;close deftest

;;Functions Taken from Lisp book, fig 4.2
(defun tokens (str test start)
  (let ((p1 (position-if test str :start start)))
   (if p1
       (let ((p2 (position-if #'(lambda (c) 
                                  (not (funcall test c)))
                              str :start p1)))
         (cons (subseq str p1 p2)
               (if p2 
                   (tokens str test p2) 
                   nil)))
       nil)))

(defun constituent (c)
  (and (graphic-char-p c)
       (not (char= c #\  ))))
;End functions for fig 4.2