On Mon, Apr 23, 2012 at 12:34 AM, Steven D'Aprano <steve+comp.lang.pyt...@pearwood.info> wrote: > On Sun, 22 Apr 2012 12:43:36 -0700, John Nagle wrote: > >> On 4/20/2012 9:34 PM, john.tant...@gmail.com wrote: >>> On Friday, April 20, 2012 12:34:46 PM UTC-7, Rotwang wrote: >>> >>>> I believe it says somewhere in the Python docs that it's undefined and >>>> implementation-dependent whether two identical expressions have the >>>> same identity when the result of each is immutable >> >> Bad design. Where "is" is ill-defined, it should raise ValueError. > > "is" is never ill-defined. "is" always, without exception, returns True > if the two operands are the same object, and False if they are not. This > is literally the simplest operator in Python. > > John, you've been using Python for long enough that you should know this. > I can only guess that you are trolling, although I can't imagine why.
Could you refrain from personal attacks? Especially considering that he said nothing unreasonable. It's you that doesn't appear to know this (relatively common? I thought it was universal...) definition of "ill-defined": http://mathworld.wolfram.com/Ill-Defined.html "() is ()" does not have one unique value in all interpretations. It can be either True or False, depending on the Python. (At least, I think this was the consensus). Therefore "is" is ill-defined in this case. -- Devin -- http://mail.python.org/mailman/listinfo/python-list
