[swift-evolution] [Proposal] Set literal and Set type syntax

[Howard Lovatt]

Sure, as I said I think the horse has bolted on this one and as you
correctly point out you can get round the problem. Its just not as neat as
just having a var arg initialiser and no array literal initialiser.

On 20 January 2016 at 15:59, David Waite <david at alkaline-solutions.com>
wrote:

> Keep in mind Array<T> cannot currently be stored in a Set (it will bridge
> to NSArray if the contained elements are compatible, which then supports
> Hashable.)
>
> The non-labelled initializer expects a formed SequenceType.
>
> If you want to use varargs, you can use Set(arrayLiteral:[1], [2], [3]) -
> so no removal of the array literal convertible conformance needed, it does
> what you want already
>
> -DW
>
>
> On Jan 19, 2016, at 6:56 PM, Howard Lovatt via swift-evolution <
> swift-evolution at swift.org> wrote:
>
> The horse has probably bolted on this one, but in general array literals
> can be confusing when used for anything other than an array. A compromise
> position might be to remove the array literal `init` from `Set` and replace
> it with a var arg `init`. It would break code, but not that much since
> `Set` is new and a migration tool could find it easily. This gives:
>
>     let sI = Set(1) // Set of Int
>     let sAI = Set([1]) // Set of array of Int
>
> On Wednesday, 20 January 2016, Greg Parker <gparker at apple.com> wrote:
>
>>
>> On Jan 18, 2016, at 2:55 PM, Howard Lovatt via swift-evolution <
>> swift-evolution at swift.org> wrote:
>>
>> On Tuesday, 19 January 2016, Jack Lawrence <jackl at apple.com> wrote:
>>
>>
>> On Jan 18, 2016, at 2:50 PM, Liam Butler-Lawrence via swift-evolution <
>> swift-evolution at swift.org> wrote:
>>
>>
>> Set("a", "b", "c”) doesn’t compile. It currently has to be
>>  Set(arrayLiteral: "a", "b", "c”). That said, I’d be satisfied with
>> removing the external parameter name “arrayLiteral”. Not only is it
>> unnecessary, but it’s confusing too: variadic parameters are not the same
>> as an Array.
>>
>>
>> init(arrayLiteral:) is there to satisfy ArrayLiteralConvertible.
>> Set([“a”, “b”, “c”]) works just fine.
>>
>>
>> Sure, but you could add another overload without the label.
>>
>>
>> Only if you break existing code. Consider this expression:
>>
>>     Set(["a", "b"])
>>
>> Is this
>> 1. a Set<String> with two elements "a" and "b"
>> 2. a Set<Array<String>> with one element ["a", "b"]
>>
>> Currently it means #1. You could change it to mean #2, but that breaks
>> existing code that expects #1. You could try to overload the no-name
>> initializer, but that will be confusing to humans in some cases.
>>
>>
>> --
>> Greg Parker     gparker at apple.com     Runtime Wrangler
>>
>>
>>
>
> --
>   -- Howard.
>
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>
>


-- 
  -- Howard.
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