pig-latin

elixir/pig-latin/lib/pig_latin.ex

@@ -0,0 +1,27 @@
+defmodule PigLatin do
+  @doc """
+  Given a `phrase`, translate it a word at a time to Pig Latin.
+  """
+
+  @vowels ~w(a e i o u)
+
+  @spec translate(phrase :: String.t()) :: String.t()
+  def translate(phrase) do
+    phrase
+    |> String.split()
+    |> Enum.map(&String.graphemes/1)
+    |> Enum.map(&translate_word/1)
+    |> Enum.join(" ")
+  end
+
+  @spec translate_word(word :: [String.t()]) :: String.t()
+  defp translate_word(["q", "u" | rest]), do: rest ++ ~w(quay)
+  defp translate_word(["x", "r" | _rest] = word), do: ay(word)
+  defp translate_word(["y", "t" | _rest] = word), do: ay(word)
+  defp translate_word([hd | _rest] = word) when hd in @vowels, do: ay(word)
+  defp translate_word([hd, x | _rest] = word) when hd in ~w(x y) and x not in @vowels, do: ay(word)
+  defp translate_word([hd | rest]), do: translate_word(rest ++ [hd])
+
+  @spec ay(word :: [String.t()]) :: [String.t()]
+  defp ay(list), do: list ++ ~w(ay)
+end