[swift-evolution] Discussion: Why is "nil" not "none"

[Muse M]

None would be similar to Null or nothing about the types in that sense
which None is not a type.
Nil would be interpret as Int, Float, String, etc



On Wed, Jun 8, 2016 at 9:17 AM, Dany St-Amant via swift-evolution <
swift-evolution at swift.org> wrote:

> No clue as to the origins, but if you insist on using none. you can do:
>
> let a : Int? = .none
> let b : Int? = .some(5)
>
> Using the simpler
>
> let a : Int? = nil
> let b : Int? = 5
>
> is just sugar.
> Maybe it was foresight to prevent people from saying, if I can do:
>
> let a : Int? = none
>
> Why can't I do:
>
> let b : Int? = some(5)
>
> And then go a step further by asking for all enum to be access without the
> leading dot; scary thought.
>
> So it may be better to stick with '.none' and sugared 'nil'.
>
> Dany
>
> Le 7 juin 2016 à 20:16, Brandon Knope via swift-evolution <
> swift-evolution at swift.org> a écrit :
>
> That's exactly the point I was going for.
>
> none makes more sense in this context than nil in my opinion
>
> Brandon
>
> On Jun 7, 2016, at 8:10 PM, Saagar Jha <saagarjha28 at gmail.com> wrote:
>
> Well, some is the opposite of none in that if I don’t have some, I have
> none. nil is just a carry-over from Objective-C.
>
> On Tue, Jun 7, 2016 at 5:07 PM Brandon Knope via swift-evolution <
> swift-evolution at swift.org> wrote:
>
>> I guess for me it comes down to this:
>>
>> *Why were some and none chosen for as the cases for Optional?*
>>
>> As an extension of that, why does nil then represent none instead of the
>> obvious none?
>>
>> There has to be a reason why it's not:
>>
>> enum Optional<T> {
>> case some(T)
>> case nil
>> }
>>
>> None seems a lot more expressive and consistent with Optional.
>>
>> I am comfortable and use to nil, but with swift being a new language, I
>> thought it was worth opening up a discussion about possibly changing
>> direction a little here.
>>
>> Thanks,
>> Brandon
>>
>> On Jun 7, 2016, at 7:57 PM, Jordan Rose <jordan_rose at apple.com> wrote:
>>
>> There are NilLiteralConvertible types other than Optional, but they’re
>> dwindling now that pointer nullability is represented by Optional. That
>> said, I’m not convinced renaming “nil” is worth it at this point.
>> Similarity with other languages is still a good thing.
>>
>> It’s true that we might not have picked nil if it hadn’t been for
>> Objective-C, but that doesn’t make it an invalid choice. There are lots of
>> things in Swift we might have done differently if it weren’t for
>> Objective-C and Cocoa.
>>
>> Jordan
>>
>>
>> On Jun 5, 2016, at 12:35, Brandon Knope via swift-evolution <
>> swift-evolution at swift.org> wrote:
>>
>>
>> Quick thought:
>>
>>
>> If optional has a .none case, wouldn't it be more consistent to rename
>> nil to none?
>>
>>
>> Also, would nil make it into Swift if not for other languages?
>>
>>
>> It also might make it somewhat clearer:
>>
>>
>> var someInt: Int? = none //looks less like a pointer and more like a
>> value of nothing
>>
>>
>> 1. It is more consistent with the optional enum
>>
>> 2. The intent is arguably clearer
>>
>> 3. nil makes it seem like it's a pointer
>>
>> 4. Would nil be included if not for prior languages? Would "none" have
>> been chosen as the keyword if nil wasn't prior art?
>>
>>
>> One disadvantage is how close it is to .none, but with how common
>> nil/none is used, some syntactic sugar might make it look nicer than always
>> having the stray .
>>
>>
>> On vacation from Orlando, poolside, with a quick thought,
>>
>> Brandon
>>
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>>
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>>
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>>
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>>
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> --
> -Saagar Jha
>
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