类的Python functools.wraps等效项 [英] Python functools.wraps equivalent for classes

问题描述

使用类定义装饰器时，如何自动转移 __ name __ ， __ module __ 和 __ doc __ ？通常，我会使用functools中的@wraps装饰器。这是我为一个班级所做的事情（这不完全是我的代码）：

When defining a decorator using a class, how do I automatically transfer over__name__, __module__ and __doc__? Normally, I would use the @wraps decorator from functools. Here's what I did instead for a class (this is not entirely my code):

class memoized:
    """Decorator that caches a function's return value each time it is called.
    If called later with the same arguments, the cached value is returned, and
    not re-evaluated.
    """
    def __init__(self, func):
        super().__init__()
        self.func = func
        self.cache = {}

    def __call__(self, *args):
        try:
            return self.cache[args]
        except KeyError:
            value = self.func(*args)
            self.cache[args] = value
            return value
        except TypeError:
            # uncacheable -- for instance, passing a list as an argument.
            # Better to not cache than to blow up entirely.
            return self.func(*args)

    def __repr__(self):
        return self.func.__repr__()

    def __get__(self, obj, objtype):
        return functools.partial(self.__call__, obj)

    __doc__ = property(lambda self:self.func.__doc__)
    __module__ = property(lambda self:self.func.__module__)
    __name__ = property(lambda self:self.func.__name__)

是否有一个标准的装饰器来自动创建名称模块和文档？另外，要自动执行get方法（我想这是用于创建绑定方法？）是否缺少任何方法？

Is there a standard decorator to automate the creation of name module and doc? Also, to automate the get method (I assume that's for creating bound methods?) Are there any missing methods?

推荐答案

每个人似乎

>>> import functools
>>> class memoized(object):
    """Decorator that caches a function's return value each time it is called.
    If called later with the same arguments, the cached value is returned, and
    not re-evaluated.
    """
    def __init__(self, func):
        self.func = func
        self.cache = {}
        functools.update_wrapper(self, func)  ## TA-DA! ##
    def __call__(self, *args):
        pass  # Not needed for this demo.

>>> @memoized
def fibonacci(n):
    """fibonacci docstring"""
    pass  # Not needed for this demo.

>>> fibonacci
<__main__.memoized object at 0x0156DE30>
>>> fibonacci.__name__
'fibonacci'
>>> fibonacci.__doc__
'fibonacci docstring'

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