Re: [Pyobjc-dev] Re: FYI: Open Source Scripting Layer For Cocoa

[Just v. R. <ju...@le...>]

Ronald Oussoren wrote:

> > Ok, that's nice for a more involved example, but not for "embedding 
> > Python in ObjC 101". Too ba, I'll try and come up with something 
> > else:-)
> 
> There is an XML-RPC library in 2.2 and 2.3, xmlrpc.org lists a number 
> of public services (from a currentTime function at Userland to Meercat 
> at O'Reilly).

The WebServicesTool example demonstrates xmlrpc already quite well.
However, it's a rather elaborate demo, so a simpler one would be very
useful as well.

That said, I feel quite strongly that any networking Cocoa app should
either use asynchronous I/O or threads, which complicates the matter
quite a bit.

It's possible to run a twisted reactor (= twisted event loop) in a
different thread (I've briefly played with that, works like a charm). It
*might* be possible to build a twisted reactor that's integrated with
the main Cocoa event loop, but that is likely quite hard. The
WebServicesTool demo uses xmlrpclib in a worker thread (in CVS at least,
I recently did a lot of work on it), but the complicatated thing about
it is that as soon as you use Cocoa stuff from a different thread, you
have to deal with autorelease pools. I've found it impossible to do even
the simplest Cocoa things (eg obj.performSelectorOnMainThread_etc.) in
PyObjC without implicitly creating autoreleased objects, so you don't
really get around wrapping your code in
NSAutoreleasePool.pyobjcPushPool() / NSAutoreleasePool.pyobjcPopPool()
blocks. See WebServicesTool for how that's done.

Just