RosettaCodeData/Task/Search-a-list/Acornsoft-Lisp/search-a-list.lisp
2023-12-16 21:33:55 -08:00

17 lines
459 B
Common Lisp

(defun first-index (word words (i . 0))
(loop
(until (null words)
(error word '! is! missing))
(until (eq word (car words))
i)
(setq words (cdr words))
(setq i (add1 i))))
(defun last-index (word words (i . 0) (last-i . nil))
(loop
(until (null words)
(cond (last-i) (t (error word '! is! missing))))
(cond ((eq word (car words))
(setq last-i i)))
(setq words (cdr words))
(setq i (add1 i))))