Programming Elixir ≥ 1.6

catch, exit, and throw

Elixir code (and the underlying Erlang libraries) can raise a second kind of error. These are generated when a process calls error, exit, or throw. All three take a parameter, which is available to the catch handler.

Here’s an example:

exceptions/catch.ex

defmodule Catch do

  def start(n) do
    try do
      incite(n)
    catch
      :exit, code   -> "Exited with code #{inspect code}"
      :throw, value -> "throw called with #{inspect value}"
      what, value   -> "Caught #{inspect what} with #{inspect value}"
    end
  end


  defp incite(1) do
    exit(:something_bad_happened)
  end

  defp incite(2) do
    throw {:animal, "wombat"}
  end

  defp incite(3) ...