Insensible Python3 Type Mapping about erlport HOT 2 CLOSED

Unfortunately there's no reliable way to distinguish a list from a "string" in Erlang. So Erlang lists mapped to List class in ErlPort which is a subclass of list but also can be converted to Unicode string with to_string() method.

I think there are at least two ways to pass str to Python 3 (both of them require some Python code unfortunately):

• A wrapper for a function can be created in Python which always convert string arguments to str. Something like the following code (not tested):

  def get_bucket(connection, bucket_name):
      return connection.get_bucket(bucket_name.to_string())

• Custom data type decoder can be used to for example convert {string, String} Erlang tuple to str in Python. The code can look like this (not tested):

  def str_decoder(value):
      if isinstance(value, tuple) and len(value) == 2 and value[0] == "string":
          value = value[1].to_string()
      return value

from erlport.

I've managed to fix this for my uses (that is fire and forget calls from Elixir to Python) with the following:
in: decode

    elif tag == 109:
        # BINARY_EXT ... In Elixir this is a BitString
        ln = len(string)
        if ln < 5:
            raise IncompleteData(string)
        length = int4_unpack(string[1:5])[0] + 5
        if ln < length:
            raise IncompleteData(string)
        stringy = string[5:length]
        return stringy.decode(), string[length:]

and in OpaqueObject:

    @classmethod
    def decode(cls, data, language):
        if isinstance(data, str):
            data = data.encode()
        if language == b"python":
            return loads(data)
        return cls(data, language)

here: https://github.com/jdoig/erlport

My requirements are very simple so I've no idea the overall impact of doing this or how this would work with erlang. Just leaving this here in case any one arrives via a search.

from erlport.