What chances do I have to instantiate, keep and serialize/deserialize to/from binary data Python classes reflecting this pattern (adopted from RFC 2246 [TLS]):

   enum { apple, orange } VariantTag;
   struct {
       uint16 number;
       opaque string<0..10>; /* variable length */
   } V1;
   struct {
       uint32 number;
       opaque string[10];    /* fixed length */
   } V2;
   struct {
       select (VariantTag) { /* value of selector is implicit */
           case apple: V1;   /* VariantBody, tag = apple */
           case orange: V2;  /* VariantBody, tag = orange */
       } variant_body;       /* optional label on variant */
   } VariantRecord;

Basically I would have to define a (variant) class VariantRecord, which varies depending on the value of VariantTag. That's not that difficult. The challenge is to find a most generic way to build a class, which serializes/deserializes to and from a byte stream... Pickle, Google protocol buffer, marshal is all not an option.

I made little success with having an explicit "def serialize" in my class, but I'm not very happy with it, because it's not generic enough.

I hope I could express the problem.

My current solution in case VariantTag = apple would look like this, but I don't like it too much

import binascii
import struct

class VariantRecord(object):
  def __init__(self, number, opaque):
    self.number = number
    self.opaque = opaque
  def serialize(self):
    out = struct.pack('>HB%ds' % len(self.opaque), self.number, len(self.opaque), self.opaque)
    return out


v = VariantRecord(10, 'Hello')
print binascii.hexlify(v.serialize())

>> 000a0548656c6c6f

Regards