[swift-evolution] Proposal: Finalization in protocol extensions and default implementations

[Adrian Zubarev]

I’d like to revive this idea I posted long time ago. There is only one thing I need to update here:
protocol MagicType: class /* missed the class constraint */ {
      
    final var foo: Int { get }
    final func boo()
}
What do you guys think? Is there any technical reason why this is not possible?
-- 
Adrian Zubarev
Sent with Airmail

Am 5. Dezember 2015 bei 16:26:23, Adrian Zubarev (adrian.zubarev at devandartist.com) schrieb:

Hello there,

I wonder if it is a good idea to be able to finalize in protocols and default implementations.

Here is an example:

protocol MagicType {
      
    final var foo: Int { get }
    final func boo()
}

class X: MagicType {
      
    final var foo: Int {
          
        return 42
    }
      
    final func boo() {
          
        print("magic")
    }
}

class Y: X {
      
    // can't override func boo or var foo in here
}

//===================================================//

protocol SomeType {}

extension SomeType {
      
    final func foo() {
          
        print("Hello World")
    }
}

class A: SomeType {}

class B: SomeType {
      
    /* this should raise an error, because the class B shouldn't */
    /* be able to override that function from SomeType */   
      
    func foo() {
        // do something else   
    }
}



— 
Regards Adrian
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