M.-A. Lemburg wrote:
If you could turn your proposal into something more like the Stackless tasklets and move the implementation to an extension module (perhaps with some extra help from new CPython APIs), then I'm sure the proposal would get more followers.
As far as I can see, it's impossible to do what I'm proposing with standard C and without language support. That's why greenlets have to resort to black magic.
"explicit is better than implicit".
This is a strange argument to be making in favour of Stackless, though, where the fact that you're dealing with suspendable code is almost completely *implicit*.
Tasklets are normal Python objects wrapping functions. The create of those tasklets is explicit, not implicit via some (special) yield burried deep in the code.
So would you be more in favour of the alternative version, where there is 'codef' but no 'cocall'?
I think an important part of the criticism is hiding the fact that you are writing a cofunction away inside the function definition itself.
The only reason I did that is because Guido turned his nose up at the idea of defining a function using anything other than 'def'. I'm starting to wish I'd stuck to my guns a bit longer in the hope of changing his sense of smell. :-)
Well, viruses will have a harder time for sure ;-) I am not aware of other use cases that would need to know the location of the stack frame in memory.
One way it can happen is that a task sets up a callback referencing something in a stack frame, and then the callback gets invoked while the task is switched out, so the referenced data isn't in the right place. I believe this is the kind of thing that was causing the trouble with Tkinter.