2016 Update

Task/Optional-parameters/Elixir/optional-parameters.elixir

@@ -0,0 +1,31 @@
+defmodule Optional_parameters do
+  def sort( table, options\\[] ) do
+    options = options ++ [ ordering: :lexicographic, column: 0, reverse: false ]
+    ordering = options[ :ordering ]
+    column   = options[ :column ]
+    reverse  = options[ :reverse ]
+    sorted = sort( table, ordering, column )
+    if reverse, do: Enum.reverse( sorted ), else: sorted
+  end
+
+  defp sort( table, :lexicographic, column ) do
+    Enum.sort_by( table, &elem( &1, column ) )
+  end
+  defp sort( table, :numeric, column ) do
+    Enum.sort_by( table, &elem( &1, column ) |> String.to_integer )
+  end
+
+  def task do
+    table = [ { "123", "456", "0789" },
+              { "456", "0789", "123" },
+              { "0789", "123", "456" } ]
+    IO.write "sort defaults "; IO.inspect sort( table )
+    IO.write " & reverse    "; IO.inspect sort( table, reverse: true )
+    IO.write "sort column 2 "; IO.inspect sort( table, column: 2)
+    IO.write " & reverse    "; IO.inspect sort( table, column: 2, reverse: true)
+    IO.write "sort numeric  "; IO.inspect sort( table, ordering: :numeric)
+    IO.write " & reverse    "; IO.inspect sort( table, ordering: :numeric, reverse: true)
+  end
+end
+
+Optional_parameters.task