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

[Bernd Nawothnig]

On 2012-04-20, dmitrey wrote:
> I have spent some time searching for a bug in my code, it was due to
> different work of "is" with () and []:
>>>> () is ()
> True

You should better not rely on that result. I would consider it to be
an implementation detail. I may be wrong, but would an implementation
that results in

() is () ==> False

be correct or is the result True really demanded by the language
specification?

>>>> [] is []
> False

Same for that.

>
> (Python 2.7.2+ (default, Oct  4 2011, 20:03:08)
> [GCC 4.6.1] )
>
> Is this what it should be or maybe yielding unified result is better?

See above.




Bernd

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