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Date: Wed, 27 Mar 2013 22:44:49 +1100
Subject: Re: Help me pick an API design (OO vs functional)
From: Chris Angelico <rosuav@gmail.com>
To: python-list@python.org
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On Wed, Mar 27, 2013 at 7:55 PM, Michael Herrmann
<michael.herrmann@getautoma.com> wrote:
> On Tuesday, March 26, 2013 5:41:42 PM UTC+1, Dave Angel wrote:
>> To go back to my sample wrapper functions, they'd look something like
>> (untested):
>>
>> def write(*args, focus=3Dfocused):
>>      focus.write(*args)
>
> I understood what you meant - I'm not so worried about the invocations, a=
s of course the parameter can be omitted if there's a default value/behavio=
ur. What I am worried about is the complexity this approach adds to several=
 functions. Yes, you could argue that one keyword argument really isn't tha=
t much, but then you have to maintain and document it for all functions tha=
t have the new keyword parameter. In other words, a single functionality th=
at is not needed 90% of the time increases the complexity of several, not r=
eally related functions. I am very grateful for your suggestions! But I don=
't think adding this keyword parameter is the way to go for us.
>

Not seeking to advocate this particular option, but it would be
possible to make a single wrapper for all your functions to handle the
focus=3D parameter:

def focusable(func):
	@functools.wraps(func)
	def wrapper(*args,focus=3DNone):
		if focus: focus.activate()
		return func(*args)
	return wrapper

Then you just decorate all your functions with that:
def write(string):
    # do something with the active window

ChrisA