Data commit

Task/Vigen-re-cipher/Clojure/vigen-re-cipher-1.clj

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+(ns org.rosettacode.clojure.vigenere
+  (:require [clojure.string :as string]))
+
+; convert letter to offset from \A
+(defn to-num [char] (- (int char) (int \A)))
+
+; convert number to letter, treating it as modulo 26 offset from \A
+(defn from-num [num] (char (+ (mod num 26) (int \A))))
+
+; Convert a string to a sequence of just the letters as uppercase chars
+(defn to-normalized-seq [str]
+  (map #'first (re-seq #"[A-Z]" (string/upper-case str))))
+
+; add (op=+) or subtract (op=-) the numerical value of the key letter from the
+; text letter.
+(defn crypt1 [op text key]
+  (from-num (apply op (list (to-num text) (to-num key)))))
+
+(defn crypt [op text key]
+  (let [xcrypt1 (partial #'crypt1 op)]
+    (apply #'str
+      (map xcrypt1 (to-normalized-seq text)
+                   (cycle (to-normalized-seq key))))))
+
+; encipher a text
+(defn encrypt [plaintext key] (crypt #'+ plaintext key))
+
+; decipher a text
+(defn decrypt [ciphertext key] (crypt #'- ciphertext key))

Task/Vigen-re-cipher/Clojure/vigen-re-cipher-2.clj

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+(ns org.rosettacode.clojure.test-vigenere
+  (:require [org.rosettacode.clojure.vigenere :as vigenere]))
+
+(let
+ [ plaintext  "Beware the Jabberwock, my son!  The jaws that bite, the claws that catch!"
+   key        "Vigenere cipher"
+   ciphertext (vigenere/encrypt plaintext  key)
+   recovered  (vigenere/decrypt ciphertext key) ]
+
+  (doall (map (fn [[k v]] (printf "%9s: %s\n" k v))
+   [ ["Original" plaintext] ["Key" key] ["Encrypted" ciphertext] ["Decrypted" recovered] ])))