black-magic 0.0.3

Decorator utility that operates on black magic

Collection of metaprogramming modules that operate on black magic!

Currently the only available module is:

• black_magic.decorator

License

To the extent possible under law, Thomas Gläßle has waived all copyright and related or neighboring rights to black-magic. This work is published from: Germany.

To the extent possible under law, the person who associated CC0 with black-magic has waived all copyright and related or neighboring rights to black-magic.

You should have received a copy of the CC0 legalcode along with this work. If not, see http://creativecommons.org/publicdomain/zero/1.0/.

black_magic.decorator

This is intended to become a more modern and flexible replacement for the the well known decorator module. This module benefits an API for more flexible usage. The behaviour of the decorator module can easily be duplicated.

Usage

You can use it just like the standard functools.wraps function:

>>> from black_magic.decorator import wraps

>>> x = []
>>> def real(a:int, b=x) -> "Returns b":
...     return b

>>> @wraps(real)
... def fake(*args, **kwargs):
...     print("Fake!")
...     return real(*args, **kwargs)

This will not only update the docstring of the fake function to look like the original but generate a wrapper function that has exactly the same signature:

>>> assert fake(1) is x   # check object-identity of default-parameter!
Fake!

>>> from inspect import getfullargspec
>>> assert getfullargspec(fake) == getfullargspec(real)

If you want to get real crazy you can even use ast exprs:

>>> import ast
>>> fake = wraps(real)(ast.Num(n=1))
>>> fake(0)
1

Under the hood

Q: This uses ugly eval code, right?

A: No, it uses abstract syntax trees to do its dynamic code generation.

Tests

This module has been tested to work on python{2.6, 2.7, 3.2, 3.3} and PyPy1.9 using Travis.