[swift-users] Calling default implementation of protocol methods as selectors

Nate Birkholz nbirkholz at gmail.com
Fri Jun 2 21:35:56 CDT 2017


protocol Foo: class {
    func bar()
}

extension Foo {
    func bar() {
         print("bar")
    }
}

class Baz: Foo {
    init() {
        let tapRecognizer = UITapGestureRecognizer(target: self, action:
#selector(bar))
    }
}

the #selector tells me: "Argument of '#selector' refers to instance method
'bar()' that is not exposed to Objective-C" and asks me to add @objc to the
method definition.

Adding @objc to the method tells me: "@objc can only be used with members
of classes, @objc protocols, and concrete extensions of classes"

Adding @objc to the protocol doesn't fix it, just introduces new issues.

"dynamic" cannot be applied to a protocol, so cannot be used alternatively.

Is there a way to get around this? If a method is called by a gesture
recognizer, is there no way to have a default protocol implementation? I'd
like to use default implementations if possible to make my code more DRY.

Is there a roadmap/plan for swift-native selector dispatch?

Thanks. I look forward to the inevitable reply revealing the dumb thing I
missed. :)

-- 
Nate Birkholz
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