kindergarten garden in elixir

elixir/kindergarten-garden/garden.exs

@@ -0,0 +1,40 @@
+defmodule Garden do
+  @doc """
+    Accepts a string representing the arrangement of cups on a windowsill and a
+    list with names of students in the class. The student names list does not
+    have to be in alphabetical order.
+
+    It decodes that string into the various gardens for each student and returns
+    that information in a map.
+  """
+
+  @default_kids ~w(alice bob charlie david eve fred ginny harriet ileana joseph kincaid larry)a
+
+  @spec info(String.t(), list) :: map
+  def info(info_string, student_names \\ @default_kids) do
+    [row1, row2] = String.split(info_string, "\n")
+    do_match_with_flowers(Enum.sort(student_names),
+                          String.graphemes(row1),
+                          String.graphemes(row2),
+                          %{})
+  end
+
+  defp do_match_with_flowers([], [], [], sofar), do: sofar
+
+  defp do_match_with_flowers([kid|rest], [], [], sofar) do
+    do_match_with_flowers(rest, [], [], Map.put(sofar, kid, {}))
+  end
+
+  defp do_match_with_flowers([kid|rest], [f1|[f2|row1]], [f3|[f4|row2]], sofar) do
+    do_match_with_flowers(rest, row1, row2,
+                          Map.put(sofar, kid,
+                                  [f1, f2, f3, f4]
+                                    |> Enum.map(&(to_flower(&1)))
+                                    |> List.to_tuple))
+  end
+
+  @flowers %{ "G" => :grass, "C" => :clover, "R" => :radishes, "V" => :violets }
+
+  defp to_flower(char), do: @flowers[char]
+
+end