[Sync Iteration] elixir/space-age/1

solutions/elixir/space-age/1/lib/space_age.ex

@@ -0,0 +1,28 @@
+defmodule SpaceAge do
+  @seconds_in_earth_year 365.25 * 24 * 60 * 60
+
+  @type planet ::
+          :mercury
+          | :venus
+          | :earth
+          | :mars
+          | :jupiter
+          | :saturn
+          | :uranus
+          | :neptune
+
+  @doc """
+  Return the number of years a person that has lived for 'seconds' seconds is
+  aged on 'planet', or an error if 'planet' is not a planet.
+  """
+  @spec age_on(planet, pos_integer) :: {:ok, float} | {:error, String.t()}
+  def age_on(:mercury, seconds), do: {:ok, seconds / (@seconds_in_earth_year * 0.2408467)}
+  def age_on(:venus, seconds), do: {:ok, seconds / (@seconds_in_earth_year * 0.61519726)}
+  def age_on(:earth, seconds), do: {:ok, seconds / @seconds_in_earth_year}
+  def age_on(:mars, seconds), do: {:ok, seconds / (@seconds_in_earth_year * 1.8808158)}
+  def age_on(:jupiter, seconds), do: {:ok, seconds / (@seconds_in_earth_year * 11.862615)}
+  def age_on(:saturn, seconds), do: {:ok, seconds / (@seconds_in_earth_year * 29.447498)}
+  def age_on(:uranus, seconds), do: {:ok, seconds / (@seconds_in_earth_year * 84.016846)}
+  def age_on(:neptune, seconds), do: {:ok, seconds / (@seconds_in_earth_year * 164.79132)}
+  def age_on(_, _), do: {:error, "not a planet"}
+end