How to check a generic type can be converted to String in swift

Question

How to check the Generic type can be converted to String ? Like below,

class Stack<T> {
    var values = [T]()

    func debugPrint() {
        values.map {
          String($0) // How to check if $0 can be converted to String?
        }
    }
}

Answer 1

If you want your class to handle only types that can be casted to a String then change the generics definition so that T conforms to LosslessStringConvertible

class Stack<T:LosslessStringConvertible> 

If on the other hand you are only interested in getting a string for printing then you can use String(describing:)

 values.map {
    String(describing:$0)
 }