Op 2005-11-03, Mike Meyer schreef <[EMAIL PROTECTED]>: > Antoon Pardon <[EMAIL PROTECTED]> writes: >>> What would you expect to get if you wrote b.a = b.a + 2? >> I would expect a result consistent with the fact that both times >> b.a would refer to the same object. > > Except they *don't*. This happens in any language that resolves > references at run time.
Python doesn't resolve references at run time. If it did the following should work. a = 1 def f(): a = a + 1 f() But letting that aside. There is still a difference between resolving reference at run time and having the same reference resolved twice with each resolution a different result. > Changing that would be changing a fundamental > - and *important* - feature of Python. Arbitrary restrictions to > prevent a single case of this from doing something people who aren't > used to suvh behavior are kludges, and would constitute a wart on the > language, pure and simple. Python already has its warts. If you want to argue that fixing this would make a bigger wart then the wart it is now. Fine I will accept that. > If you think this is bad, you should consider Jensen's device. It uses > call-by-name, which Python doesn't have. Actually, I would have thought it very interesting should python have provided some choice in parameter semantics. >> I think it even less sane, if the same occurce of b.a refers to two >> different objects, like in b.a += 2 > > That's a wart in +=, nothing less. The fix to that is to remove += > from the language, but it's a bit late for that. > > <mike Well we agree that there is a wart somewhere. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
