串的模式匹配的灵丹妙药

药剂的功能模式匹配

iex> handle_result = fn
...>   {:ok, result} -> IO.puts "Handling result..."
...>   {:ok, _} -> IO.puts "This would be never run as previous will be matched beforehand."
...>   {:error} -> IO.puts "An error has occurred!"
...> end

iex> handle_result.({:ok, some_result}) # Handling result...
iex> handle_result.({:error}) # An error has occurred!