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

[Saagar Jha]

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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-- 
-Saagar Jha
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