-
Notifications
You must be signed in to change notification settings - Fork 818
/
subclass_with_meta.py
50 lines (40 loc) · 1.58 KB
/
subclass_with_meta.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
from inspect import isclass
from .props import props
class SubclassWithMeta_Meta(type):
_meta = None
def __str__(cls):
if cls._meta:
return cls._meta.name
return cls.__name__
def __repr__(cls):
return f"<{cls.__name__} meta={repr(cls._meta)}>"
class SubclassWithMeta(metaclass=SubclassWithMeta_Meta):
"""This class improves __init_subclass__ to receive automatically the options from meta"""
def __init_subclass__(cls, **meta_options):
"""This method just terminates the super() chain"""
_Meta = getattr(cls, "Meta", None)
_meta_props = {}
if _Meta:
if isinstance(_Meta, dict):
_meta_props = _Meta
elif isclass(_Meta):
_meta_props = props(_Meta)
else:
raise Exception(
f"Meta have to be either a class or a dict. Received {_Meta}"
)
delattr(cls, "Meta")
options = dict(meta_options, **_meta_props)
abstract = options.pop("abstract", False)
if abstract:
assert not options, (
"Abstract types can only contain the abstract attribute. "
f"Received: abstract, {', '.join(options)}"
)
else:
super_class = super(cls, cls)
if hasattr(super_class, "__init_subclass_with_meta__"):
super_class.__init_subclass_with_meta__(**options)
@classmethod
def __init_subclass_with_meta__(cls, **meta_options):
"""This method just terminates the super() chain"""