why () is () and [] is [] work in other way?

[Adam Skutt]

On Apr 26, 1:48 am, John Nagle <na... at animats.com> wrote:
> On 4/25/2012 5:01 PM, Steven D'Aprano wrote:
>
> > On Wed, 25 Apr 2012 13:49:24 -0700, Adam Skutt wrote:
>
> >> Though, maybe it's better to use a different keyword than 'is' though,
> >> due to the plain English
> >> connotations of the term; I like 'sameobj' personally, for whatever
> >> little it matters.  Really, I think taking away the 'is' operator
> >> altogether is better, so the only way to test identity is:
> >>      id(x) == id(y)
>
> > Four reasons why that's a bad idea:
>
> > 1) The "is" operator is fast, because it can be implemented directly by
> > the interpreter as a simple pointer comparison (or equivalent).
>
>     This assumes that everything is, internally, an object.  In CPython,
> that's the case, because Python is a naive interpreter and everything,
> including numbers, is "boxed".  That's not true of PyPy or Shed Skin.
> So does "is" have to force the creation of a temporary boxed object?

That's what C# does AFAIK.  Java defines '==' as value comparison for
primitives and '==' as identity comparison for objects, but I don't
exactly know how one would do that in Python.

Adam