Added Map.from_struct/1

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>

Author: joshnuss

lib/elixir/lib/map.ex

@@ -38,5 +38,22 @@ defmodule Map do
  end, map1, map2
  end
 
+ @doc """
+ Converts a struct to map.
+
+ ## Example
+
+ defmodule User do
+ defstruct [:name]
+ end
+
+ Map.from_struct(%User{name: "valim"})
+ #=> %{name: "valim"}
+
+ """
+ def from_struct(struct) do
+ :maps.delete(:__struct__, struct)
+ end
+
  def equal?(%{} = map1, %{} = map2), do: map1 === map2
 end

lib/elixir/test/elixir/map_test.exs

@@ -124,6 +124,11 @@ defmodule MapTest do
  end
  end
 
+ test "map from struct" do
+ assert Map.from_struct(%ExternalUser{name: "valim"}) == %{name: "valim", age: 27}
+ assert Map.from_struct(%{name: "valim"}) == %{name: "valim"}
+ end
+
  defmodule LocalUser do
  defmodule NestedUser do
  defstruct []