[swift-evolution] Proposal: Python's "in" and "not in" syntactic sugar

[Adrian Kashivskyy]

I agree with Felix.

> I wouldn't be in favor of introducing a keyword that replaces a method call.

Note that `not in` operator actually consists of two operators – `not`, which would be an alias for `!` and `in` which would be an alias for `contains()`.

As said by my preceding speakers, there are no operator-like keywords in Swift so far, and In my opinion, there shouldn't be any.


By the way,

> Most programmers would probably love using them though.

Please do no speak in the name of majority without actual numbers. :)


Pozdrawiam – Regards,
Adrian Kashivskyy

> Wiadomość napisana przez Félix Cloutier via swift-evolution <swift-evolution at swift.org> w dniu 17.12.2015, o godz. 17:16:
> 
> I don't like it because it introduces a second way to do something that's already quite easy.
> 
> It's impossible for the Swift compiler to enforce that people never create a `contains` method (or create it without adhering to whatever protocol `in` uses behind the scenes), so in my opinion this would increase the burden of creating types that feel first-class.
> 
> As it's already been said before, Swift has been very careful with keywords so far. I wouldn't be in favor of introducing a keyword that replaces a method call.
> 
> Félix
> 
>> Le 17 déc. 2015 à 10:48:02, Jeremy Pereira via swift-evolution <swift-evolution at swift.org> a écrit :
>> 
>> 
>>> On 17 Dec 2015, at 15:59, Amir Michail via swift-evolution <swift-evolution at swift.org> wrote:
>>> 
>>> 
>>>> On Dec 17, 2015, at 9:51 AM, Brent Royal-Gordon <brent at architechies.com> wrote:
>>>> 
>>>>> if “hello” in [“hello, there”] { … }
>>>>> 
>>>>> if “hello” not in [“hello, there”] { … }
>>>> 
>>>> Swift is extremely sparing with keywords in operator position; the only ones I can think of off the top of my head are `is` and `as`, and even those aren’t actually operators. You’re proposing to introduce one as syntactic sugar for [array].contains(elem), and introduce an even more bizarre two-word operator for ![array].contains(elem). I don’t think that’s gonna fly.
>>> 
>>> Most programmers would probably love using them though.
>> 
>> 
>> If that’s the case, I’d be in the minority. 
>> 
>> I’d rather use [“hello", “there”].contains(“hello”). That might just be my background though which is heavily object oriented.
>> 
>>> 
>>>> 
>>>> -- 
>>>> Brent Royal-Gordon
>>>> Architechies
>>>> 
>>> 
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