Decorating classes for product_types

gistfile1.txt

gbl_product_types={}

class product_type:
  def __init__(self, product_types):
      self._product_types = product_types;
      
  def __call__(self, cls):
      gbl_product_types[cls.__name__] = self._product_types
      class Wrapped(cls):
        pass
      return Wrapped

class Base(object):
  pass
    
@product_type(["a"])
class Task(Base):    
  pass

@product_type(["b"])
class Mixin(Base):
  pass

class Composite(Mixin, Task):
  pass


def get_product_types(cls):
    result = []
    def recursive_search(cls):
        for base in cls.__bases__:
            recursive_search(base)
        if cls.__name__ in gbl_product_types.keys():    
            result.extend(gbl_product_types[cls.__name__])
    recursive_search(cls)
    return result

print("gbl_product_types= {0}".format(gbl_product_types))
print("Mixin = {0}".format(get_product_types(Mixin)))
print("Task = {0}".format(get_product_types(Task)))
print("Composite = {0}".format(get_product_types(Composite)))

# python ./task_product_type.py 
# output:
# gbl_product_types= {'Task': ['a'], 'Mixin': ['b']}
# Mixin = ['b']
# Task = ['a']
# Composite = ['b', 'a']

You can definitely avoid odd names - several ways. Here is one:

>>> registry = {}
>>> 
>>> def product_types(*tags):
...   def wrapper(cls):
...     registry[cls] = list(tags)
...     return cls
...   return wrapper
... 
>>> @product_types('bob', 'jill')
... class Foo(object):
...   pass
... 
>>> Foo()
<__main__.Foo object at 0x7f6fe2e28550>
>>> registry
{<class '__main__.Foo'>: ['bob', 'jill']}
>>>