Author uriyyo
Recipients ncoghlan, rhettinger, serhiy.storchaka, uriyyo
Date 2020-11-30.08:31:05
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Message-id <1606725065.68.0.497251775054.issue42455@roundup.psfhosted.org>
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Content
Let's wait for Nick.

I have found great examples to show how decorator_factory can simplify things.

dataclasses.dataclass
```
def dataclass(cls=None, /, *, init=True, repr=True, eq=True, order=False,
              unsafe_hash=False, frozen=False):
    def wrap(cls):
        return _process_class(cls, init, repr, eq, order, unsafe_hash, frozen)

    # See if we're being called as @dataclass or @dataclass().
    if cls is None:
        # We're called with parens.
        return wrap

    # We're called as @dataclass without parens.
    return wrap(cls)
```
```
@functools.decorator_factory
def dataclass(cls, /, *, init=True, repr=True, eq=True, order=False,
              unsafe_hash=False, frozen=False):
    return _process_class(cls, init, repr, eq, order, unsafe_hash, frozen)
```

functools.lru_cache
```
def lru_cache(maxsize=128, typed=False):
    if isinstance(maxsize, int):
        # Negative maxsize is treated as 0
        if maxsize < 0:
            maxsize = 0
    elif callable(maxsize) and isinstance(typed, bool):
        # The user_function was passed in directly via the maxsize argument
        user_function, maxsize = maxsize, 128
        wrapper = _lru_cache_wrapper(user_function, maxsize, typed, _CacheInfo)
        wrapper.cache_parameters = lambda : {'maxsize': maxsize, 'typed': typed}
        return update_wrapper(wrapper, user_function)
    elif maxsize is not None:
        raise TypeError(
            'Expected first argument to be an integer, a callable, or None')

    def decorating_function(user_function):
        wrapper = _lru_cache_wrapper(user_function, maxsize, typed, _CacheInfo)
        wrapper.cache_parameters = lambda : {'maxsize': maxsize, 'typed': typed}
        return update_wrapper(wrapper, user_function)

    return decorating_function
```
```
@decorator_factory
def lru_cache(user_function, /, maxsize=128, typed=False):
    if isinstance(maxsize, int):
        # Negative maxsize is treated as 0
        if maxsize < 0:
            maxsize = 0
    elif maxsize is not None:
        raise TypeError(
            'Expected first argument to be an integer, a callable, or None')

    wrapper = _lru_cache_wrapper(user_function, maxsize, typed, _CacheInfo)
    wrapper.cache_parameters = lambda : {'maxsize': maxsize, 'typed': typed}
    return update_wrapper(wrapper, user_function)
```
History
Date User Action Args
2020-11-30 08:31:05uriyyosetrecipients: + uriyyo, rhettinger, ncoghlan, serhiy.storchaka
2020-11-30 08:31:05uriyyosetmessageid: <1606725065.68.0.497251775054.issue42455@roundup.psfhosted.org>
2020-11-30 08:31:05uriyyolinkissue42455 messages
2020-11-30 08:31:05uriyyocreate