Add exercise 2 from chapter 23

Author: Bernard Pietraga

chapter_23/more_cool_stuff_2.exs

@@ -0,0 +1,34 @@
+defmodule ParseSygil do
+  def sigil_z(lines, _options) do
+    String.rstrip(lines)
+    |> String.split("\n")
+    |> Enum.map(&String.split(&1, ","))
+    |> Enum.map(fn x -> convert_to_number(x) end)
+  end
+
+  defp convert_to_number(column) do
+    Enum.map(column, fn x ->
+                       case Float.parse(x) do
+                         {float, _} -> float
+                         _          -> x
+                       end
+                     end)
+  end
+end
+
+ExUnit.start
+
+defmodule ParseSygilTest do
+  import ParseSygil
+  use ExUnit.Case
+
+  test "parse CSV like string" do
+    expected = ~z"""
+    1,2,3
+    cat,dog
+    """
+
+    assert expected == [[1.0, 2.0, 3.0], ["cat", "dog"]]
+  end
+
+end