[swift-evolution] Object declarations

[Thorsten Seitz]

> Am 11.12.2015 um 23:28 schrieb Marc Knaup <marc at knaup.koeln>:
> 
> Actually it's both - an object and a type. It's an object which describes itself.

If it was a type then I would expect to be able to 
- derive a subclass from it
- use it as type in variable or parameter declarations

I don't think either makes sense, or does it?

> Btw. I have the same problem with enum cases. They're values so why are they uppercase?

Hmm, good point. Guess I'm just used to it :-)

-Thorsten

>> On Fri, Dec 11, 2015 at 11:25 PM, Thorsten Seitz <tseitz42 at icloud.com> wrote:
>> I like it. Just a minor suggestion: as an object is a value and not a type it should have a name starting with lower case, i.e.
>> 
>> object globalResource { ... }
>> 
>> -Thorsten 
>> 
>>> Am 11.12.2015 um 23:07 schrieb Marc Knaup via swift-evolution <swift-evolution at swift.org>:
>>> 
>>> Hey guys,
>>> 
>>> I am working on a proposal which touches (and could even partially depend on) another interesting concept which I think would be a great addition for Swift.
>>> 
>>> Object declarations could be a way to declare a class or struct with exactly one instance. They are perfect for singletons, anonymous subclasses and to anonymously implement a protocol.
>>> 
>>> Here some examples how it could look like:
>>> 
>>> // singleton
>>> object GlobalResource {
>>>     func doSomething() { … }
>>> }
>>> 
>>> let resource = GlobalResource
>>> 
>>> // could all be the same
>>> resource.doSomething()
>>> GlobalResource.doSomething()
>>> GlobalResource.Type.doSomething()
>>> 
>>> 
>>> // anonymous subclass
>>> class ViewController: UIViewController {
>>> 
>>>     override func loadView() {
>>>         view = object: UIView {
>>>             // configure view
>>>         }
>>>     }
>>> }
>>> 
>>> 
>>> // anonymous protocol implementation
>>> protocol TapHandler {
>>>     func handleTap()
>>> }
>>> 
>>> view.tapHandler = object: TapHandler {
>>>     func handleTap() {
>>>         // …
>>>     }
>>> }
>>> 
>>> 
>>> Kotlin is an example for a a modern language which uses this concept:
>>> https://kotlinlang.org/docs/reference/object-declarations.html
>>> 
>>> 
>>> What do you think about such an addition?
>>> 
>>> _______________________________________________
>>> swift-evolution mailing list
>>> swift-evolution at swift.org
>>> https://lists.swift.org/mailman/listinfo/swift-evolution
> 
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