Primes by Trial Division - Common LISP
25 September 2016
Changes from the INTERLISP version:
| Common LISP | INTERLISP |
|---|---|
| lowercase | UPPERCASE |
| + | PLUS |
| < | LESSP |
| mod | REMAINDER |
| defun | DEFINEQ |
| block nil | PROG NIL |
| mapcar func list | MAPCAR list func |
Variant A
(defun primes (n)
(prog (count primes)
(setq count 3)
(setq primes (list 2))
NEXT (cond ((< (length primes) n)
(cond ((member 0 (mapcar #'(lambda (x) (mod count x)) primes)) nil)
(T (nconc primes (list count)))))
(T (return primes)))
(setq count (+ count 1))
(go NEXT)))
Variant B
(defun divp (n list)
(block nil (mapc #'(lambda (p)
(cond ((zerop (mod n p)) (return-from divp T)))) list)
(return-from divp nil)))
(defun primes (n)
(prog (count primes)
(setq count 3)
(setq primes (list 2))
NEXT (cond ((< (length primes) n)
(cond ((divp count primes) nil)
(T (nconc primes (list count)))))
(T (return primes)))
(setq count (+ count 1))
(go NEXT)))