lecture 04

lectures/04/lec4.ex

@@ -0,0 +1,36 @@
+defmodule Lec4 do
+  def create(n \\ 4) do
+    Enum.map(1..n, fn _ -> parent = self(); spawn(fn -> loop(parent) end) end)
+  end
+
+  def info(pid) when is_pid(pid) do
+    case Process.info(pid, [:trap_exit, :links]) do
+      nil -> {pid, :dead}
+      x -> {pid, x}
+    end
+  end
+
+  def info(pids) when is_list(pids) do
+    Enum.map(pids, &info/1)
+  end
+
+  def trap_exit(pid) do
+    send(pid, :trap_exit)
+  end
+
+  def link(pid, other) do
+    send(pid, {:link, other})
+  end
+
+  defp loop(parent) do
+    receive do
+      :trap_exit ->
+        Process.flag(:trap_exit, true)
+      {:link, other} ->
+        Process.link(other)
+      x ->
+        send(parent, x)
+    end
+    loop(parent)
+  end
+end