bottle_song

elixir/bottle-song/lib/bottle_song.ex

@@ -0,0 +1,28 @@
+defmodule BottleSong do
+  @moduledoc """
+  Handles lyrics of the popular children song: Ten Green Bottles
+  """
+
+  defp verse(n) do
+    bottle_sense = fn
+      0 -> "No green bottles"
+      1 -> "One green bottle"
+      2 -> "Two green bottles"
+      3 -> "Three green bottles"
+      4 -> "Four green bottles"
+      5 -> "Five green bottles"
+      6 -> "Six green bottles"
+      7 -> "Seven green bottles"
+      8 -> "Eight green bottles"
+      9 -> "Nine green bottles"
+      10 -> "Ten green bottles"
+    end
+
+    "#{bottle_sense.(n)} hanging on the wall,\n#{bottle_sense.(n)} hanging on the wall,\nAnd if one green bottle should accidentally fall,\nThere'll be #{String.downcase(bottle_sense.(n-1))} hanging on the wall."
+  end
+
+  @spec recite(pos_integer, pos_integer) :: String.t()
+  def recite(start_bottle, take_down) do
+    Enum.map_join(0..(take_down - 1), "\n\n", &verse(start_bottle - &1))
+  end
+end