Design thought for callbacks

[Chris Angelico]

On Sun, Feb 22, 2015 at 2:45 AM, Cem Karan <cfkaran2 at gmail.com> wrote:
> OK, so if I'm reading your code correctly, you're breaking the cycle in your object graph by making the GUI the owner of the callback, correct?  No other chunk of code has a reference to the callback, correct?

Correct. The GUI engine ultimately owns everything. Of course, this is
a very simple case (imagine a little notification popup; you don't
care about it, you don't need to know when it's been closed, the only
event on it is "hit Close to destroy the window"), and most usage
would have other complications, but it's not uncommon for me to build
a GUI program that leaves everything owned by the GUI engine.
Everything is done through callbacks. Destroy a window, clean up its
callbacks. The main window will have an "on-deletion" callback that
terminates the program, perhaps. It's pretty straight-forward.

ChrisA