Dual conditions in D and Python

[Dennis Ritchie via Digitalmars-d-learn]

On Thursday, 21 May 2015 at 17:43:25 UTC, Jonathan M Davis wrote:
> No C-based language allows what python does, and based on 
> operators work in
> C-based languages, what python is doing simply doesn't fit or 
> make sense.
> What happens in C/C++/D/Java/C#/etc. land is that 4 <= 5 
> results in a bool,
> at which point you'd end up with a comparison between that bool 
> and 6, which
> is _not_ something that you want. But with other operators _is_ 
> very much
> what you'd want. Operator chaining works in the same way across 
> all
> operators in C-based languages, and trying to make 4 <= 5 <= 6 
> be equivalent
> to 4 <= 5 && 5 <= 6 would make it so that they weren't 
> consistent. And it
> wouldn't make the language any more powerful, because you can 
> quite easily
> just do 4 <= 5 && 5 <= 6 instead of 4 <= 5 <= 6. It only costs 
> you a few
> characters and results in the language being far more 
> consistent. I'm
> honestly quite surprised that python would allow such a thing, 
> but they seem
> to do a lot of stuff that most programmers from C-based 
> languages
> (especially C++) would think is crazy.
>
> - Jonathan M Davis

Yes, of course, some of Python's design for C ++ - programmers 
will look crazy, but they are worth it :)

elif instead of else if:
http://rextester.com/WOSH30608

The parallel exchange values:
http://rextester.com/TPUD51604