It seems to me, that D is a language where python like chaining would be right at home.

writeln(1 < 2 < 3 < 4 > 3 == 3); // true


So why doesn't D have it already ;-)

On Monday, 21 February 2022 at 09:29:56 UTC, forkit wrote:
> It seems to me, that D is a language where python like chaining would be right at home.
>
> writeln(1 < 2 < 3 < 4 > 3 == 3); // true
>

I've no clue whatsoever how to interpret that mess, nor do I have any desire of obtaining said clue.

On Monday, 21 February 2022 at 09:48:53 UTC, Stanislav Blinov wrote:
> On Monday, 21 February 2022 at 09:29:56 UTC, forkit wrote:
>> It seems to me, that D is a language where python like chaining would be right at home.
>>
>> writeln(1 < 2 < 3 < 4 > 3 == 3); // true
>>
>
> I've no clue whatsoever how to interpret that mess, nor do I have any desire of obtaining said clue.

It's just a chain..

just like...

cat.meow().eat().sleep().play();

which, the more verbose way, is:

cat.meow();
cat.eat();
cat.sleep();
cat.play();

On Monday, 21 February 2022 at 10:27:08 UTC, forkit wrote:
> On Monday, 21 February 2022 at 09:48:53 UTC, Stanislav Blinov wrote:
>> On Monday, 21 February 2022 at 09:29:56 UTC, forkit wrote:
>>> It seems to me, that D is a language where python like chaining would be right at home.
>>>
>>> writeln(1 < 2 < 3 < 4 > 3 == 3); // true
>>>
>>
>> I've no clue whatsoever how to interpret that mess, nor do I have any desire of obtaining said clue.
>
> It's just a chain..
>
> just like...
>
> cat.meow().eat().sleep().play();
>
> which, the more verbose way, is:
>
> cat.meow();
> cat.eat();
> cat.sleep();
> cat.play();

I think you've misunderstood what this is doing in python. From the language definition https://docs.python.org/3/reference/expressions.html#comparisons, op1 b op2 c ... y opN z is equivalent to a op1 b and b op2 c and ... y opN z, except that each expression is evaluated at most once.

e.g. 2 < x < 5 means x > 2 and x < 5, i.e. x is between 2 and 5. It only applies to comparisons and it's a genuinely useful bit of syntactic sugar that is not confusing when used properly.

On 2/21/22 02:27, forkit wrote:

>>> writeln(1 < 2 < 3 < 4 > 3 == 3); // true

> cat.meow().eat().sleep().play();

That misunderstanding (or miscommunication) is reason enough why such loose semantics should not be in any serious programming language.

So, Python is happy with the fact that the result of 1 < 2 is sometimes Boolean but sometimes 2? (Note that in chaining, not the result but one of the arguments is used; and the chosen argument happens to be the one that's "close" to the next operator. Ha ha! :) How convenient... And why would 'a > b < c' not mean "a is greater than b and a is less than c" or "a is greater than b OR b is less than c"? I can guess: They picked the only semantic that could possibly be explained that could work. And then they must have slapped on a rationale: "Checking more than two conditions is very common in Programming Languages." I found that inaccurate sentence copy-pasted in multiple blog posts:

- They must mean "more than one condition", not "two"

- They mean "program", not "programming language"

- They ommit the supposed domain where that claim may be true (I might have found a use for this feature perhaps once, if ever? Not sure...)

I think this is an example of blind leading blind in that community.

Ali

On 2/21/22 10:48, Stanislav Blinov wrote:
> On Monday, 21 February 2022 at 09:29:56 UTC, forkit wrote:
>> It seems to me, that D is a language where python like chaining would be right at home.
>>
>> writeln(1 < 2 < 3 < 4 > 3 == 3); // true
>>
> 
> I've no clue whatsoever how to interpret that mess, 

It's standard mathematical notation.

E.g.: https://en.wikipedia.org/wiki/Fence_(mathematics)

> nor do I have any desire of obtaining said clue.
A C compiler with a clue:

mess.c: In function ‘main’:
mess.c:4:23: warning: comparisons like ‘X<=Y<=Z’ do not have their mathematical meaning [-Wparentheses]
    4 |         printf("%d", X<=Y<=Z);
      |                      ~^~~

This is why it's disallowed in D (it's basically always an accident).