[Python-Dev] Twisted Isn't Specific (was Re: Trial balloon: microthreads library in stdlib) (original) (raw)

Greg Ewing greg.ewing at canterbury.ac.nz
Thu Feb 15 06:25:35 CET 2007

Thomas Wouters wrote:

I don't like the idea of something in the Python installation deciding which reactor to use.

I wouldn't mind if some way were provided of changing the reactor if you want. I'd just like to see a long term goal of making it unnecessary as far as possible.

In any case, your idea requires a lot of changes in external, non-Python code -- PyGTK simply exposes the GTK mainloop, which couldn't care less about Python's idea of a perfect event reactor model.

On unix at least, I don't think it should be necessary to change gtk, only pygtk. If it can find out the file descriptor of the connection to the X server, it can plug that into the reactor, and then call gtk_main_iteration_do() whenever something comes in on it.

A similar strategy ought to work for any X11-based toolkit that exposes a function to perform one iteration of its main loop.

Mileage on other platforms may vary.

The PerfectReactor can be added later, all current reactors aliased to it, and no one would have to change a single line of code.

Sure.

The other side to all this is the client side, i.e. the code that installs event callbacks. At the moment there's no clear direction to take, so everyone makes their own choice -- some use asyncore, some use Twisted, some use the gtk event loop, some roll their own, etc.

If it were made known that asyncore or some other thing in the stdlib was intended to become the standard, then it would give people some guidance as to how to write future event-driven code.

-- Greg

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