On Wednesday 18 May 2005 17:39, Guido van Rossum wrote:
I believe that in the discussion about PEP 343 vs. Nick's PEP 3XX (http://members.iinet.net.au/~ncoghlan/public/pep-3XX.html, still awaiting PEP moderator approval I believe?) the main difference is that Nick proposes a way to inject an exception into a generator; and I've said a few times that I like that idea.
I'd like to propose to make that a separate PEP, which can combine elements of PEP 288 and PEP 325. Summary:
- g.throw(type, value, traceback) causes the specified exception to be thrown at the place where the generator g is currently suspended. .. - There's a new exception, GeneratorExit, which can be thrown to cause a generator to clean up. A generator should not yield a value in response to this exception.
- g.close() throws a GeneratorExit exception in the generator, and catches it (so g.close() itself does not raise an exception). g.close() is idempotent -- if the generator is already closed, it is a no-op. If the generator, against the rules, yields another value, it is nevertheless marked closed.
+1 We're currently using python generators to handle concurrency in a single thread, and this allows a simple scheduler to have a clean way of sending generators a generator shutdown message. (Currently we have to do it another way that is specific to the style of wrapped generator) If you need a volunteer to code this - should it go through, I'm willing to have a go at this. (I can't do this though for 3 weeks or so though due to a crunch at work, and I might be in over my head in offering this.) Michael. -- Michael Sparks, Senior R&D Engineer, Digital Media Group Michael.Sparks@rd.bbc.co.uk, http://kamaelia.sourceforge.net/ British Broadcasting Corporation, Research and Development Kingswood Warren, Surrey KT20 6NP This e-mail may contain personal views which are not the views of the BBC.