In Swift, how to generically limit function to types that understand T + T

Question

I would like to have a generic function that can use the plus operator on two values.

class funccalc {
    func doAdd(x:T,y:T) -> T {
        ret         


        

Answer 1

You should do as that answer suggested. Create a protocol for your use and extend all of the classes that you want to use it. Then make sure T implements that protocol in your method signature.

You can't use an "addable" protocol because there isn't one in swift. The swift library actually creates a function + for each valid addition operations. Command-click on something like Int to see where all of these are defined. It will look something like this:

//....
func +(lhs: Int8, rhs: Int8) -> Int8
func +(lhs: UInt16, rhs: UInt16) -> UInt16
func +(lhs: Int16, rhs: Int16) -> Int16
func +(lhs: UInt32, rhs: UInt32) -> UInt32
func +(lhs: Int32, rhs: Int32) -> Int32
//etc...