A). Write a function NEW-LIST that takes a number as its argument and constructs

Question

A). Write a function NEW-LIST that takes a number as its argument and constructs a list of that length containing all Ts. For example,

-> (new-lit 5)

-> (T T T T T)

B). The Lisp function LENGTH counts the number of elements in the top level of a list. Write a function ALL-LENGTH of one argument that counts the number of atoms that occur in a list at all levels.  Thus, the following lists will have the following ALL-LENGTHs.

            (A B C)                                   => 3

            ((A (B C) D (E F))      => 6

            (NIL NIL (NIL NIL) NIL )   => 5

Explanation / Answer

(A)

Online URL for testing : http://ideone.com/u5Qhna

(defun NEW-LIST(max)
(let ((result nil))
(dotimes (i max)
(push 'T result))
(nreverse result)))

(print (NEW-LIST 5))

(print (NEW-LIST 10))

Output:

(B)

Online URL for testing : http://ideone.com/YL1WhQ

(defun ALL-LENGTH (exp &optional (if-null 1))
(cond ((null exp) if-null)
((atom exp) 1)
(t (+ (ALL-LENGTH (first exp) 1)
(ALL-LENGTH (rest exp) 0)))))

(print
   ( ALL-LENGTH '(A B C)
   )
)

(print
   ( ALL-LENGTH '((A (B C) D (E F)))
   )
)

(print
   ( ALL-LENGTH '(NIL NIL (NIL NIL) NIL )
   )
)

Output:

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