Bien que la réponse par @Dogbert est tout à fait correcte, il y a un truc, on pourrait utiliser lorsque des messages d'erreur ne peut pas être plus que, disons, 140 symboles (messages d'erreur alias twitter taille.)
defmodule Test do
@pattern "error happened"
defp status({:error, @pattern <> _rest }, state),
do: IO.puts "Matched leading"
Enum.each(1..140, fn i ->
defp status({:error,
<<_ :: binary-size(unquote(i)),
unquote(@pattern) :: binary,
rest :: binary>>}, state),
do: IO.puts "Matched"
end)
Enum.each(0..140, fn i ->
defp status({:error, <<_ :: binary-size(unquote(i))>>}, state),
do: IO.puts "Unmatched"
end)
# fallback
defp status({:error, message}, state) do
cond do
message =~ "error happened" -> IO.puts "Matched >140"
true -> IO.puts "Unatched >140"
end
end
def test_status({:error, message}, state),
do: status({:error, message}, state)
end
Tests:
iex|1 ▶ Test.test_status {:error, "sdf error happened sdfasdf"}, nil
Matched
iex|2 ▶ Test.test_status {:error, "sdf errors happened sdfasdf"}, nil
Unmatched
iex|3 ▶ Test.test_status {:error, "error happened sdfasdf"}, nil
Matched leading
iex|4 ▶ Test.test_status {:error,
...|4 ▷ String.duplicate(" ", 141) <> "error happened sdfasdf"}, nil
Matched >140