Add the default frequency factory.

src/cipher_analytical_machine/cli/actions/cracking.clj

@@ -9,7 +9,8 @@
   (let [analyzer (:analyzer options)
         message (:message options)
         symbols (:symbols options)
-        frequencies symbol-frequencies/english-letter-frequencies]
+        frequencies (-> (get options :language "en")
+                        (symbol-frequencies/default-frequency-factory))]
     (cond
       (= analyzer "Chi^2")
       (caesar-analyzers/get-plaintext message symbols frequencies)

src/cipher_analytical_machine/symbols/frequencies.clj

@@ -77,3 +77,16 @@
    \  0.138
 })
 
+(defn default-frequency-factory
+  "Returns a default map of letter frequencies for a language"
+  [language-code]
+  (cond
+    (= language-code "en")
+    english-letter-frequencies
+
+    (= language-code "uk")
+    ukrainian-letter-frequencies
+
+    :else
+    english-letter-frequencies))
+

test/cipher_analytical_machine/symbols/frequencies_test.clj

@@ -9,3 +9,13 @@
       (is (= "etaoinsrhldcumfpgwybvkxjqz"
              (map-to-string symbol-map))))))
 
+(deftest default-frequency-factory-test
+  (testing "Factory supports languages: English (en), Ukrainian (uk). If language code is unidentified, then it must have the 'en'."
+    (are [language-code expected-map-size]
+        (->> (default-frequency-factory language-code)
+             count
+             (= expected-map-size))
+      "en"           26
+      "uk"           34
+      "Maybe a code" 26)))
+