CODEWITHSUNDEEP
swiftgenerics
LettersBa
LettersBa

Reputation: 767

Extending a non-Generic to a generic type

I have this code that represents a non-generic Struct:

struct rum {
    var prop = "Hello"
}

let's suppose that I need to create an extension for this Struct to receive generic types. For this, I try this code:

extension rum <T>{

    func release(bo: T){
        println(T)
    }

}

But Xcode gives me many errors, that rum does not have a generic type. But the idea is to create a non-generic Struct and transform it into a generic. Is it possible?

Upvotes: 0

Views: 182

Answers (1)

Sergey Kalinichenko
Sergey Kalinichenko

Reputation: 726669

If rum were a class, you would get more flexibility, because you could derive a generic class from it, and define an extension on that generic class. However, struct is a value type, so you cannot derive a class from it.

Since rum is not generic struct, you need to make the extension method generic, like this:

extension rum {

    func release<T>(bo: T){
        println(prop)
        println(bo)
    }

}

Unfortunately, this means that all extension methods that you wish to be generic need to be decorated with <T>.

Upvotes: 2

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