get-annotations 0.1.1

A backport of Python 3.10's inspect.get_annotation() function

get-annotations

A backport of Python 3.10's inspect.get_annotations() function

Install

pip3 install -U get-annotations

Usage

try:
  from inspect import get_annotations
except ImportError:  # Python is older than 3.10
  from get_annotations import get_annotations

def foo(x: int) -> str: ...

print(get_annotations(foo))
# {'x': <class 'int'>, 'return': <class 'str'>}

If your module uses from __future__ import annotations, you'll want to set eval_str=True, otherwise get_annotations will return strings:

from __future__ import annotations
import typing as t

def bar(x: t.List[MyObject]): ...

class MyObject:
  pass

print(get_annotations(bar))
# {'x': 't.List[MyObject]'}

print(get_annotations(bar, eval_str=True))
# {'x': typing.List[__main__.MyObject]}

Note that it does not work with old-style forward ref annotations, such as t.List["MyObject"]:

>>> from typing import List
>>> def foo(a: int) -> List["MyObject"]: ...
...
>>> class MyObject: ...
...
>>> print(get_annotations(foo, eval_str=True)) # Note that 'MyObject' is returned as a string!
{'a': <class 'int'>, 'return': typing.List[ForwardRef('MyObject')]}
>>>
>>> print(get_annotations(foo, eval_str=False)) # Identical
{'a': <class 'int'>, 'return': typing.List[ForwardRef('MyObject')]}

If you really don't want to use from __future__ import annotations for some reason, you can surround an entire type annotation in quotes to forward ref it:

>>> def foo(a: int) -> "List[MyObject]": ...
...
>>> print(get_annotations(foo, eval_str=True)) # This works now
{'a': <class 'int'>, 'return': typing.List[__main__.MyObject]}
>>>
>>> print(get_annotations(foo, eval_str=False)) # For comparison
{'a': <class 'int'>, 'return': 'List[MyObject]'}

License

MIT

Contact

A library by Shawn Presser. If you found it useful, please consider joining my patreon!

My Twitter DMs are always open; you should send me one! It's the best way to reach me, and I'm always happy to hear from you.

• Twitter: @theshawwn
• Patreon: https://www.patreon.com/shawwn
• HN: sillysaurusx
• Website: shawwn.com