Is this valid ?

[castironpi at gmail.com]

On Mar 20, 6:06 pm, Steven D'Aprano <st... at REMOVE-THIS-
cybersource.com.au> wrote:
> On Thu, 20 Mar 2008 15:09:08 +0100, Rolf van de Krol wrote:
>
> > John Machin wrote:
> >> Of course. You can chain comparisons as much as you like and is
> >> (semi-)sensible, e.g.
>
> > Hmm, 'of course' is not the correct word for it.
>
> Not at all. The Original Poster tried something, and it worked. There
> were two alternatives:
>
> (1) Writing a == b == 2 is valid.
>
> (2) In the sixteen years that Python has been publicly available, with
> tens of thousands or more developers using it, nobody had noticed that
> Python had a bug in the compiler which incorrectly allowed a == b == 2
> until Stef Mientki came along and discovered it.
>
> Given those two alternatives, (2) would be very surprising indeed, and so
> I think "of course" is well justified.
>
> That Python allows chaining comparisons this way isn't really surprising.
> That's a very natural thing to do. What's surprising is that other
> languages *don't* allow chaining comparisons, but force you to write the
> inefficient and (sometimes) confusing "(a == 2) and (b == 2)" instead.

You see a couple of occurrences in natural language-- I'm wondering
where the majority of NL settles.

>>> a is a is a
True

Do we do math on booleans on some level or in some contexts?  Maybe a
"with syntaxchangeA:" is in the future.