closures

Background: I'm hooking on windows COM object. The method used is vtable modification. say we have an instance of interface A named instance , it contains oldmethod in the interface, I replaced with newmethod . However, in my newmethod I need to know the address of oldmethod so that I can call oldmethod after doing my own thing. It is not safe to store the address of oldmethod in a global variable, since there might be more than one implementation behind interface A , let's say there are two implementations, class A1 and class A2 . Thus my newmethod needs to store both A1->oldmethod and A2-

I searched a lot and haven't found anything that really helped to solve my problem... I'm trying to build a simple UIControl from scratch, like a UIButton. It can't be subclass of UIControl for particular reasons. I need this control to do something like this: myControl.addTarget(target: AnyObject?, action: Selector, forControlEvents: UIControlEvents) The problem is that the implementation of the method that execute this selector when the button is touched needs the "performSelector:" method. Swift doesn't have a "performSelector:". So I taught it could be implemented using closures. I couldn

I'm trying to build a counter in python with the property of closure. The code in the following works: def generate_counter(): CNT = [0] def add_one(): CNT[0] = CNT[0] + 1 return CNT[0] return add_one However when I change the list CNT to a var, it did not work: def generate_counter1(): x = 0 def add_one(): x = x + 1 return x return add_one when I print the closure property of an instance, I found the __closure__ of the second case is none: >>> ct1 = generate_counter() >>> ct2 = generate_counter1() >>> print(ct1.__closure__[0]) <cell at 0xb723765c: list object at 0xb724370c> >>> print(ct2._

This is the slideshow that we used: http://www.littlewebthings.com/projects/blinds/ and this is the JS file: http://www.littlewebthings.com/projects/blinds/js/jquery.blinds-0.9.js However, this slideshow doesn't have a setting that makes it go through each image automatically. You still have to click on the numbers below it to see the images. Does anybody know what to add into the javascript code to make it go through each image automatically? Thanks! This solution uses closures and recursion. var SlideChanger = function(seconds_each) { var index = -1; // on the first cycle, index will be set

I've been trying to learn about closures, but one thing still perplexes me. If I have the following code: var add = (function () { var counter = 0; return function () {return counter += 1;} })(); add(); add(); add(); // Returns "3" If I call add() three times, why dosen't it set counter to zero every time, then return the anonymous funtion that increments counter by one? Does it skip over it once the self-invoking function runs? Sorry if the question seems simple, I'm having a hard time understanding it. Any help would be greatly appreciated. If I call add() three times, why dosen't it set