bread-and-potions

elixir/bread-and-potions/lib/rpg.ex

@@ -0,0 +1,58 @@
+defmodule RPG do
+  defmodule Character do
+    defstruct health: 100, mana: 0
+  end
+
+  defmodule LoafOfBread do
+    defstruct []
+  end
+
+  defmodule ManaPotion do
+    defstruct strength: 10
+  end
+
+  defmodule Poison do
+    defstruct []
+  end
+
+  defmodule EmptyBottle do
+    defstruct []
+  end
+
+  # Add code to define the protocol and its implementations below here...
+  defprotocol Edible do
+    @moduledoc """
+    Protocol definition for interaction between Characters and Items
+    """
+    @type item() :: LoafOfBread.t() | ManaPotion.t() | Poison.t() | EmptyBottle.t()
+    @spec eat(item(), Character.t()) :: {nil | item(), Character.t()}
+    def eat(item, character)
+  end
+
+  defimpl Edible, for: LoafOfBread do
+    @moduledoc """
+    Edible implimentation for LoafOfBread
+    """
+    @spec eat(LoafOfBread.t(), Character.t()) :: {nil, Character.t()}
+    def eat(%LoafOfBread{}, %Character{health: health} = character),
+      do: {nil, %{character | health: health + 5}}
+  end
+
+  defimpl Edible, for: ManaPotion do
+    @moduledoc """
+    Edible implimentation for ManaPotion
+    """
+    @spec eat(ManaPotion.t(), Character.t()) :: {EmptyBottle.t(), Character.t()}
+    def eat(%ManaPotion{strength: strength}, %Character{mana: mana} = character),
+      do: {%EmptyBottle{}, %{character | mana: mana + strength}}
+  end
+
+  defimpl Edible, for: Poison do
+    @moduledoc """
+    Edible implimentation for Poison
+    """
+    @spec eat(Poison.t(), Character.t()) :: {EmptyBottle.t(), Character.t()}
+    def eat(%Poison{}, %Character{} = character),
+      do: {%EmptyBottle{}, %{character | health: 0}}
+  end
+end