Generic Functions

Type parameters are declared in angle brackets after the function name and stand for a concrete type supplied at the call site. One generic definition replaces a family of identical overloads:

// Regular function
func Add(x: int, y: int) -> int {
    return x + y;
}

// Generic function
func Min<T>(x: T, y: T) -> T {
    return x < y ? x : y;
}

The type parameter T is bound to a concrete type for each call. It is usually inferred from the arguments, so the call site looks like any other:

let a = Min(3, 7);       // T = int
let b = Min(2.5, 1.0);   // T = float64

A single generic definition therefore replaces the family of near-identical overloads you would otherwise write by hand.

See Also

• Function Declaration — the non-generic form
• Type Aliases — naming the types a generic is instantiated with