Custom Types

Array Types

You can use arrays as types.

let Person = [name: String, age: UInt]
let grow = (person: Person) -> person.age++

let lu = new Person("Lu", 28)
lu:grow()

Function Types

You can use functions as types.

let Even = [n] => n % 2 == 0
let half = [n: Even] => n / 2

half(4) //2
half(3) //Type Error

Checking

You can check a value's type with the is or type function.

3:is(Number) //true
3:is(UInt32) //true

3:type //UInt32

let Vector = [x: Int, y: Int]
let position = Vector(3, 2)

position:type //Person
position:is(Vector) //true
position:is(Int[2]) //true