Guido van Rossum wrote: > [Guido] > >>>Let me give you what you expect. If all the "X if C else Y" syntax >>>does is prevent that atrocity from ever being introduced, it would be >>>worth it. :) > > > [Steve] > >>Well, fine. However, it does allow atrocities like >> >>func(f for f in lst if f > -1 if f < 0 else +1) > > > No it doesn't! Inside an 'if' (of any flavor), further ifs have to be > nested. So you'd have to write > > func(f for f in lst if f > (-1 if f < 0 else +1)) > > or perhaps > > func(f for f in lst if (f > -1 if f < 0 else +1)) > > But I doubt you meant to write +1 where True could have sufficed. :) > :)
All that said, inside an "if" is hardly the best place for a conditional of any kind. Clearly such usage can go down as abuse. > An if-else expression has lower priority than anything else except > lambda; the expression > > lambda x: x if x >= 0 else -x > > is equivalent to > > lambda x: (x if x >= 0 else -x) > That's about the only way it would make sense, I suppose. > >>I realise that any chosen syntax is subject to abuse, but a conditional >>expression in a (currently allowed) conditional context will be >>guaranteed obscure. Your original instinct to omit conditional >>expressions was right! > > > Now you've pushed me over the edge. I've made up my mind now, "X if C > else Y" it will be. I hope to find time to implement it in Python 2.5. > Let it be as controversial as bool or @decorator, I don't care. > Not before time, either. If this ends the discussion then I'll consider I've done everyone a favour. Sometimes no decision is worse than the wrong decision ;-). regards Steve -- Steve Holden +44 150 684 7255 +1 800 494 3119 Holden Web LLC www.holdenweb.com PyCon TX 2006 www.python.org/pycon/ _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
