IO.puts("Hello, World!")

defmodule Math do def zero?(0), do: true def zero?(x) when is_integer(x), do: false
end

defmodule SomeModule do require Logger @doc """ iex> SomeModule.do_something("Richard") {:ok, "Message sent!"} iex> SomeModule.do_something("Jian") {:error, "Invalid phone number"} iex> SomeModule.do_something("Erlich") {:error, "Not found"} """ def do_something(name) do with {:ok, phone_number} <- look_up(name), :sent <- send_text(phone_number) do {:ok, "Message sent!"} end end def do_something_and_log_error(name) do with {:ok, phone_number} <- look_up(name), :sent <- send_text(phone_number) do {:ok, "Message sent!"} else {:error, error_msg} = error -> Logger.error(error_msg) error end end defp look_up("Richard"), do: {:ok, "+15629998888"} defp look_up("Jian"), do: {:ok, "+864009999999"} defp look_up(_), do: {:error, "Not found"} defp send_text("+1" <> _phone_number), do: :sent defp send_text(_), do: {:error, "Invalid phone number"}
end