Another update from ingydotnet^djgoku

Task/Caesar-cipher/Elixir/caesar-cipher.elixir

@@ -0,0 +1,18 @@
+defmodule Caesar_cipher do
+  defp set_map(map, range, key) do
+    org = Enum.map(range, &List.to_string [&1])
+    {a, b} = Enum.split(org, key)
+    Enum.zip(org, b ++ a) |> Enum.into(map)
+  end
+
+  def encode(text, key) do
+    map = Map.new |> set_map(?a..?z, key) |> set_map(?A..?Z, key)
+    String.codepoints(text) |> Enum.map_join(fn c -> Dict.get(map, c, c) end)
+  end
+end
+
+text = "The five boxing wizards jump quickly"
+key = 3
+IO.puts "Original:  #{text}"
+IO.puts "Encrypted: #{enc = Caesar_cipher.encode(text, key)}"
+IO.puts "Decrypted: #{Caesar_cipher.encode(enc, -key)}"