== Packson

Packson is a json (de)serializer for python3 objects.
It uses annotations in the style of jackson.


The basic version determines the types for (de)serialization from the __init__ function in the involved classes. Polymorphism is supported, so derived classes can (de)serialized from a superclass.

A complex example showing many things at once (I did not have time to write out many simpler examples)

{{{
from jackson.ObjectMapper import ObjectMapper
from jackson.JsonSubTypes import JsonSubTypes
from jackson.JsonTypeInfo import JsonTypeInfo
from jackson.JsonTypeInfo import Id,As
from typing import Dict,List,Set
import json

class Props:
    '''
    compound class with properties, used for testing 
    '''
    def __init__(self, age:int, name:str):
        if age<0:
            raise ValueError("age must be >0, got "+str(age))
        self._age=age
        self._name=name;
    def __str__(self):
        return self._name+","+str(self._age)
    def getage(self):
        return self._age
    def getname(self):
        return self._name
    def __eq__(self, other):
        return isinstance(other, self.__class__) and \
            self._name==other._name and self._age==other._age


@JsonSubTypes(["test.ObjectMapperTest.Bear"])
@JsonTypeInfo(use=Id.NAME, include=As.WRAPPER_OBJECT)
class Animal:
    pass
    
    
class Bear(Animal):
    def __init__(self, props:Props):
        self._props=props
            
    def __str__(self):
        return "Bear["+str(self._props)+"]"
        
    def getprops(self):
        return self._props
    def __eq__(self, other):
        return isinstance(other, self.__class__) and \
            self._props==other._props

jackson=ObjectMapper()


obj=Bear(Props(1,'bruno'))
res=jackson.toJson(obj)
print("result:"+str(res))
bson={'Bear': {'props': {'age': 1, 'name': 'bruno'}}}
res=jackson.parse(bson, Animal)
print("Deserialized an Animal! -->"+str(res))

}}}