Pascal's triangle: Difference between revisions

=={{header|Clojure}}==

For n < 1, prints nothing, returns nil. Copied from the Common Lisp implementation above, but with local functions and explicity tail-call-optimized recursion (recur).

(defn pascal [n]

(let [newrow (fn newrow [lst ret]

(if lst

(recur (rest lst) (conj ret (+ (first lst) (or (second lst) 0))))

ret))

genrow (fn genrow [n lst]

(when (< 0 n)

(do (println lst)

(recur (dec n) (conj (newrow lst []) 1)))))]

(genrow n [1])))

(pascal 4)