Assignment 2, Lisp Notes and Review, Due September 10, 2007

Functions:

· (car <list>)

o (car (1 2 3)) => 1

· (cdr <list>)

o (cdr (1 2 3)) => (2 3)

o (cdr (1)) => NIL

· (list <element1 element2 element3 ….. elementN>)

o (setf fullhouse (list 2 2 3 3 3)))

· (setf <variable [list or atom]> <value>)

o (setf eat 8)

o (setf eatthis (list pie cake))

· (length <list>)

o (length fullhouse) => 5

· (defun <function name> <arg list> (exp1) (exp2) (exp3) ….(expN) )

· (cond ( (condition 1) (exp1)..(expN)) ( (condition 2) (exp1)..(expN)) (t (exp1)..(expN)) )

· (append (list1) (list2))

o (append (list 1 2 3) (list 4 5)) => (1 2 3 4 5)

· (cons (list1) (list2))

o (cons (list 1 2 3) (list 4 5)) => ((1 2 3) 4 5)

· (eval (list))

o (eval (car (1 2 3)) => 1

Examples:

(defun init ()

(setf big (list 1 2 3 4 5 6 7 8 9 10))

(setf fullhouse (list 2 2 2 3 3))

)

(defun lastone (list)

(cond

(( = (length list) 1)

(first list)

)

( t

(print list)

(lastone (cdr list))

)

(defun sumList(addlist)

(cond

((= (length addlist) 1)

(car addlist)

)

(+ (car addlist)(sumList(cdr addlist)))

)

(defun average (list)

(/ (sumList list) (length list))

)

(defun middleNum (nums)

(setf mid (/ (length nums) 2))

(getNum mid nums)

)

(defun getNum (mid nums)

(cond

((= 1 mid)

(car nums)

)

(getNum (- mid 1) (cdr nums))

)

(defun insultMe (message)

(append (list 'Yo 'Mamma) message)

)

Write a function that reverses a list.
(revMe (list 1 2 3)) => (3 2 1)
Wirte a function that counts the number of items in a list, do not use the length function.
Write a factorial function that uses recursion.
(fact (3)) => 6