Decode outputs

[ayrat555]

This PR should be merged after #34
Resolves #25

Now to decode/encode output you should pass data type :output as the third parameter. By default, the third parameter is :input For example

      selector = %FunctionSelector{
        function: "getVersion",
        input_names: [],
        inputs_indexed: nil,
        method_id: <<13, 142, 110, 44>>,
        returns: [:string],
        type: :function,
        types: []
      }

      data =
        "0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000d312e302e342b6136396337363300000000000000000000000000000000000000"
        |> Base.decode16!(case: :lower)

      expected_result = ["1.0.4+a69c763"]

      assert expected_result == ABI.decode(selector, data, :output)
      assert data == ABI.encode(selector, expected_result, :output)

[InoMurko]

KUDOS!

[vbaranov]

@ayrat555 shouldn't we provide backward compatibility with the previous versions of the library by allowing ABI.decode, ABI.encode with two input parameters?

[ayrat555]

@vbaranov the third parameter is optional. So it will work like before

[vbaranov]

@ayrat555 I've tried example, you provided, but tried to decode with 2 parameters. Here is the result:

iex(6)> ABI.decode(selector, data)
** (MatchError) no match of right hand side value: {:ok, <<0, 0, 0, 0>>, <<0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 32, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...>>}
    (ex_abi 0.4.0) lib/abi/type_decoder.ex:143: ABI.TypeDecoder.decode/3

[ayrat555]

@vbaranov I think you're trying to decode output with input types. Different data should be provided for input

[ayrat555]

@vbaranov the function doesn't accept any parameters

[vbaranov]

@ayrat555

I think you're trying to decode output with input types. Different data should be provided for input

Maybe, we should gracefully handle this error?

the function doesn't accept any parameters

what do you mean? which one?

[ayrat555]

Maybe, we should gracefully handle this error?

I can work on it as a separate issue. It's the same behaviour that was before my changes

what do you mean? which one?

getVersion - types: [] - so nothing to decode