A sip of Elixir

iex> pid = spawn(fn -> 1 + 2 end)
#PID<0.44.0>

iex> Process.alive?(pid)
false

iex> pid = spawn(fn ->
  Process.sleep(:infinity)
end)
#PID<0.44.0>

iex> Process.alive?(pid)
true

iex> Process.exit(pid, :kill)
true

iex> x = 1

iex> Task.async(fn -> x = 3 end) |> Task.await
3

iex> x
1

send(
  process_b,
  {:hello, self()}
)

receive do
  reply ->
    IO.puts(reply)
end

receive do
  {:hello, from} ->
    send(from, "Hello there")

  other ->
    handle(other)
end

iex> pid = spawn(fn ->
  Process.sleep(5_000)
  raise "error"
end)
#PID<0.118.0>

iex> send(pid, :request)
:request

iex> receive do
  response -> response
end
... blocks forever since process will die ...

iex> pid = spawn_link(fn ->
  Process.sleep(5_000)
  raise "error"
end)
#PID<0.118.0>

iex> send(pid, :request)
:request

iex> receive do
  response -> response
end
... after 5 seconds when pid dies, so does iex ...
... crash report ...
... iex restarts ...

defmodule Ping do
  use GenServer

  def start_link(_) do
    GenServer.start_link(__MODULE__, nil, name: __MODULE__)
  end

  def init(state) do
    {:ok, state}
  end

  def handle_call(:ping, _from, state) do
    {:reply, :pong, state}
  end
end

iex> Ping.start_link(nil)
{:ok, #PID<0.232.0>}

iex> GenServer.call(Ping, :ping)
:pong

iex> GenServer.call(Ping, :wrong)
... crashes and worker is dead now ...

iex> Supervisor.start_link([Ping], strategy: :one_for_one)
{:ok, #PID<0.239.0>}

iex> GenServer.call(Ping, :wrong)
... crashes, but supervisor restarts the worker...

iex> GenServer.call(Ping, :ping)
:pong