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;;Author: Joey Baranski                                               ;;
;;Description: ECE478 Homework #1 Solutions                           ;;
;;Modified: 2004-01-08                                                ;;
;;Some code based on ECE478 Lectures                                  ;;
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;;q. 1 http://www.ece.pdx.edu/~baranskj/robotics

;;q. 2 test: car, cdr, caddr, cons, list, set, setq, prog, progn, cond, 
;;           atom, minusp, numberp, go, nconc, 
;;           reverse, nreverse, print, trace

;;**NOTE: The following functions are not available in the version of 
;;          ANSI Common Lisp that I am using: 
;;          greaterp, plus, minus, traceset, debug, number


;;**See results in attached output file**

         
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;;  function: trans
;;written by: Joey Baranski (based on ece478 examples)
;;  modified: 2004-01-10
;;       pre: nil
;;      post: tests for lisp functions
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;:    
(defun trans()
  (setq a '(a 2 (3 z q)))   ;; equivalent to (set 'a '(blah)) 
  (set 'c 7654) ;set an atom, note that setq symbol == set 'symbol
  (set 'b '(x q (r (s)) t)) ;; equivalent to (setq b '(blah))
  (list '(1 2 3) '(a b 5) '(22 (44 bb) xx))
  (atom a) ;returns nil
  (atom c) ;returns true
  (atom (car a)) ;returns true
  (atom (cdr a)) ;returns nil
  (set 'r 'abcdefg) ;sets symbol a = symbol abcdefg
  (setq s 'gfedcba) ;equivalent to set 'symbol
  (cons 'l 'm) ;lists l & m in dotted notation
  (cons a (cons '(x y z) '(q 38 657))) ;lists a and the rest of the stuff in dotted notation
  (evenp 3) ;returns nil, not an even number
  (evenp 4) ;T even number
  (oddp 3) ;returns t, odd #
  (oddp 4) ;returns nil, even #
  (setq tl '(dog cat chicken rabbit turtle frog))
  (car tl) ;returns dog
  (cdr tl) ;returns chicken through crow
  (first tl) ;same as car
  (rest tl) ;same as cdr
  (cadr tl) ;car of the cdr of tl so, cat
  (caddr tl) ;car of the cdr of the cdr of tl, so chicken
  (nth 3 tl) ;return nth element of a zero based list so rabbit
  (nth 0 tl) ;return dog
  (nth 100 tl) ;return nil
  (progn '(do not return me) '(please return me)) ;returns last thing, so returns '(please return me)
  (nconc '(a b c) '(1 2 3)) ;returns (a b c 1 2 3)
 ; (tagbody 
 ;   (setq a1 10)
 ;   (setq b1 12)
 ;   here
 ;   (print '(here))
 ;   there
 ;   (print 'there))
 ;   (if (> a1 b1) 
 ;     (go there)
 ;     (go here)
 ;   ) 
 ; )

)

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;;  function: alertifminus
;;written by: Joey Baranski (based on ece478 examples)
;;  modified: 2004-01-10
;;       pre: list or atom x
;;      post: returns a some message if negative number, some other
;;            message if positive number, and some other message is not
;;            an atom or number
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(defun alertifminus(x)
  (if (and (atom x) (numberp x)) ;redundant to check number and atom (just wanted to use and)
    (if (minusp x)
        (format t "~A is a negative number" x)
        (format t "~A is a positive number or zero" x)
    )
    (print "The parameter you supplied is not a number")
  )
)


;;q. 3 reverse the order of atoms in a list
;;   **See results in attached output file**
(setq a '(First 2nd Third Fourth 5th))
(reverse a) ;prints reversed list to screen preserves order of list a
(setq nl (reverse a)) ;sets nl to reverse of list a preserves order of list a
(nreverse a) ;reverses order of a, so atoms in list a is now in reverse

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;;  function: rv
;;written by: Joey Baranski (based on ece478 examples)
;;  modified: 2004-01-10
;;       pre: arbitrary data structure s
;;      post: a reversed copy of arbitrary data structure s
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(defun rv(s)
 (cond (
         (atom s) s
       )

  (T 
    (
      list (rv (cdr s)) (car s)
    )
  ))
 
)


;;q. 4 copy an arbitrary list data structure on all levels except atoms

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;;  function: copystruct
;;written by: Joey Baranski (based on ece478 examples)
;;  modified: 2004-01-08
;;       pre: arbitrary data structure s
;;      post: a copy of arbitrary data structure s
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(defun copystruct(s)
  (cond (
         (atom s) s
        )

  (T 
    (cons (copystruct (car s))
    (copystruct (cdr s)))))

)