[Pythonmac-SIG] Porting a Tkinter application to Cocoa: question about datatypes

[Kevin Walzer]

Ronald Oussoren wrote:
> 

> The major exception to this is Key-Value Observing (also known as Cocoa 
> bindings).  Cocoa bindings requires that objects emit events when they 
> are mutated (append an item, set the value for a key in a dict, ...). 
> Sadly enough Python doesn't have the hooks that are required to emit 
> these events for pure python objects.  Adding this support requires some 
> low-level changes to python and I'm not sure if this can be done without 
> adversely affecting the performance of the interpreter.

Interesting. Are Cocoa bindings analogous to the updating and binding 
mechanism in Tk? For instance, in Tkinter, I can assign a value to an 
object, then update that value later in another function via the 
StringVar() mechanism. For instance, in in my self.drawGUI function, I 
can do this:

         self.status = StringVar()
         self.status.set('Ready')

then in another function, I can call this:

         self.status.set('Process terminated')

and the value of the label widget will be updated. Was this 
functionality hard to manage or missing in Objective-C/Cocoa before the 
"Cocoa Binding" stuff was added?

-- 
Kevin Walzer
Code by Kevin
http://www.codebykevin.com