post-scarcity/lisp/member.lisp

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No EOL
324 B
Common Lisp

(set! nil? (lambda (o) (= o nil)))
(set! member (lambda
(item collection)
"Return `t` if this `item` is a member of this `collection`, else `nil`."
(cond
((nil? collection) nil)
((= item (car collection)) t)
(t (member item (cdr collection))))))