Comments on: Progress with Python Decorators and Meta Classes

By: J5

J5 — Fri, 22 Apr 2005 04:57:27 +0000

Ah, excelent. No reason for the function. I think I needed some coffee at that point Now that I see how this all fits together it looks like I have everything I need to do what I want. Thanks for all the info.

By: James

James — Fri, 22 Apr 2005 04:38:01 +0000

Note that you can assign arbitrary attributes to a function, so in your method() decorator, you could just as easily pass through the original function object, setting _dbus_method_name on it.

Also, is there any reason for attaching a function to the method object, rather than just attaching the information directly as an attribute? I’d probably do something like “func.is_dbus_method = True”, then in your metaclass check if getattr(func, ‘is_dbus_method’, False) is true.

By: J5

J5 — Fri, 22 Apr 2005 03:39:30 +0000

No reason for not passing keywords. This was just a quick hack so I could wrap my head around decorators and metaclasses. I wanted to brainstorm the design and see how things could possibly fit together. I think with the try/except block I’m just going to get the function object’s dictionary and do a has_key(). It is much cleaner that way. Also I don’t think I will need a function there and will instead pass in some structured data.

By: Andrew

Andrew — Fri, 22 Apr 2005 00:46:28 +0000

def method(func):
    def decorator(self, *args):
        func(self, *args)
	
    def _dbus_method_name():
        return func.__name__
	
    decorator._dbus_method_name = _dbus_method_name
    return decorator

Don't forget to return the value of func(self, *args)! Also, is it intentional to accept *args but not **kwargs?

        method_list = []
        for func in dct.values():
	    try:
	        method_name = func._dbus_method_name()
	        method_list.append(method_name)
            except:
                pass

Yeah I don't like the try-except here either. Changing it to be an "except AttributeError" would help a little, but it would be best as:

	    try:
	        dbus_method_name = func._dbus_method_name
            except AttributeError:
                pass 
            else:
	        method_list.append(dbus_method_name())