Initial Commit

genserver.exs

@@ -0,0 +1,38 @@
+defmodule Stack do
+  use GenServer
+
+  # Client
+
+  def start_link(default) when is_binary(default) do
+    GenServer.start_link(__MODULE__, default)
+  end
+
+  def push(pid, element) do
+    GenServer.cast(pid, {:push, element})
+  end
+
+  def pop(pid) do
+    GenServer.call(pid, :pop)
+  end
+
+  # Server (callbacks)
+
+  @impl true
+  def init(elements) do
+    initial_state = String.split(elements, ",", trim: true)
+    {:ok, initial_state}
+  end
+
+  @impl true
+  def handle_call(:pop, _from, state) do
+    [to_caller | new_state] = state
+    {:reply, to_caller, new_state}
+  end
+
+  @impl true
+  def handle_cast({:push, element}, state) do
+    new_state = [element | state]
+    {:noreply, new_state}
+  end
+end
+