Sha256: 4857767605477664e7ee858b4d905d7203840c4ae9a8149e19f2375c6706292d
Contents?: true
Size: 498 Bytes
Versions: 104
Compression:
Stored size: 498 Bytes
Contents
(ns isbn-verifier)
(defn is-in? [xs x] (some #(= x %) xs))
(defn isbn-chars [isbn]
(filter #(is-in? [\0 \1 \2 \3 \4 \5 \6 \7 \8 \9 \X] %) isbn))
(defn isbn? [isbn]
(let [chars (isbn-chars isbn)
nums (map #(if (= \X %) 10 (Character/digit % 10)) chars)]
(and (-> chars butlast (is-in? \X) not)
(= 10 (count chars))
(as-> nums x
(map #(* %1 %2) (range 10 0 -1) x)
(reduce + x)
(mod x 11)
(zero? x)))))
Version data entries
104 entries across 104 versions & 1 rubygems