Python - making decorators with optional arguments

Question

from functools import wraps

def foo_register(method_name=None):
    """Does stuff."""
    def decorator(method):
        if method_name is None:
            method.gw_method = method.__name__
        else:
            method.gw_method = method_name
        @wraps(method)
        def wrapper(*args, **kwargs):
            method(*args, **kwargs)
        return wrapper
    return decorator

Example: The following decorates my_function with foo_register instead of ever making it to decorator.

@foo_register
def my_function():
    print('hi...')

Example: The following works as expected.

@foo_register('say_hi')
def my_function():
    print('hi...')

If I want it to work correctly in both applications (one using method.__name__ and one passing the name in), I have to check inside of foo_register to see if the first argument is a decorator, and if so, I have to: return decorator(method_name) (instead of return decorator). This sort of "check to see if it's a callable" seems very hackish. Is there a nicer way to create a multi-use decorator like this?

P.S. I already know that I can require the decorator to be called, but that's not a "solution". I want the API to feel natural. My wife loves decorating, and I don't want to ruin that.

Answer 1

Glenn - I had to do it then. I guess I'm glad that there is not a "magic" way to do it. I hate those.

So, here's my own answer (method names different than above, but same concept):

from functools import wraps

def register_gw_method(method_or_name):
    """Cool!"""
    def decorator(method):
        if callable(method_or_name):
            method.gw_method = method.__name__
        else:
            method.gw_method = method_or_name
        @wraps(method)
        def wrapper(*args, **kwargs):
            method(*args, **kwargs)
        return wrapper
    if callable(method_or_name):
        return decorator(method_or_name)
    return decorator

Example usage (both versions work the same):

@register_gw_method
def my_function():
    print('hi...')

@register_gw_method('say_hi')
def my_function():
    print('hi...')