Example usage of the Parser module, which crashes the parent process when it crashes

parser_usage.iex

# Create a new Parser process
iex(2)> {:ok, pid} = Parser.start_link()
{:ok, #PID<0.118.0>}

# Verify the process is alive
iex(3)> Process.alive?(pid)
true

# Send it a valid message
iex(4)> GenServer.call(pid, "100")
100

# Send it an invalid message
iex(5)> GenServer.call(pid, "tyler")
** (EXIT from #PID<0.115.0>) evaluator process exited with reason: an exception was raised:
  # Stacktrace here