Swift Tutorial - Swift Generics

• « Previous

Generics means parameterized types. Using generics, we can create a single class that works with different types of data. A class, protocal, or method that operates on a parameterized type is called generic.

To use generics, you must add <T> after a function name.

Then you can substitute T in place of the type name.

Example

The following code shows how to define function with generic parameters.

Type Checking
class Person {
    func profile() -> String {
        return "Person"
    }
}

class Employee: Person {
    override func profile() -> String {
        return "Employee"
    }
}
var p1 = Person()
var e1 = Employee()

func printPerson<T>(p:T){
    let o = p as Person
    println(o.profile())
}

printPerson (p1)
printPerson (e1)

Example 2

The following code shows how you would add type checking to your function.

class Person {
    func profile() -> String {
        return "Person"
    }
}

class Employee: Person {
    override func profile() -> String {
        return "Employee"
    }
}

func printPerson<T>(p:T){
    if p is Person || p is Employee{
        let o = p as Person
        println(o.profile())
    }
    else{
        println("\(p) is not supported.")
    }
}

var p1 = Person()
var e1 = Employee()

printPerson (p1)
printPerson (e1)

var s = "ABC"
printPerson(s)

• « Previous