primitive Red
primitive Blue
primitive Green

// Let Colour be an alias for the union type (Red | Blue | Green)
type Colour is (Red | Blue | Green)

// ColourList is a constant representing the union type
primitive ColourList
    fun apply(): Array[Colour] =>
        [Red; Green; Blue]

actor Main
    new create(env: Env) =>
        for colour in ColourList().values() do
            env.out.print("I should be printing a colour
                but I don't know how to cast to string")
        end

// Type aliases can also be used to give simpler names to complex types
interface HasName
    fun name(): String

interface HasAge
    fun age(): U32

interface HasFeelings
    fun feeling(): String

// Let Person be an alias for the intersection of those three types
// This makes it easier to refer to
type Person is (HasName & HasAge & HasFeelings)

// You can do this with traits as well as interfaces.