create a generic method to return result type in swift

To create a generic method that returns a result type in Swift, we can use associated types. Associated types allow us to define a placeholder type that is used as part of the method's signature, and can later be specified when the method is called.

Here is an example of a generic method that uses an associated type to return a result:

main.swift
protocol ResultProtocol {
    associatedtype ResultType
    func getResult() -> ResultType
}

struct ResultInt: ResultProtocol {
    typealias ResultType = Int
    var result: Int
    func getResult() -> Int {
        return result
    }
}

struct ResultString: ResultProtocol {
    typealias ResultType = String
    var result: String
    func getResult() -> String {
        return result
    }
}

func getResult<T: ResultProtocol>(result: T) -> T.ResultType {
    return result.getResult()
}

let intResult = ResultInt(result: 42)
let stringResult = ResultString(result: "Hello, World!")

let intValue = getResult(result: intResult)
let stringValue = getResult(result: stringResult)

print(intValue) // Output: 42
print(stringValue) // Output: "Hello, World!"
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In this example, we define a protocol ResultProtocol that includes an associated type ResultType and a method getResult() that returns a value of that associated type.

We then define two structs ResultInt and ResultString that conform to ResultProtocol by defining their associated types and implementing the getResult() method.

Finally, we define a generic function getResult() that takes a parameter of type T that conforms to ResultProtocol and returns a value of that parameter's associated type ResultType by calling its getResult() method.

We can then create instances of ResultInt and ResultString and pass them to getResult() to get their underlying values.