Swift: Enums and Pattern Matching

playground.swift

// SwiftCurriculum: https://github.com/brennanMKE/SwiftCurriculum
// Blog Post: https://medium.com/swift-curriculum/swift-enums-and-pattern-matching-8da7286c1060
// Swift Version: 3.0

import Foundation

enum Filling {
    case chocolate
    case cream
    case fruit
}

enum Donuts {
    case sugar(count: Int)
    case sprinkles(count: Int)
    case chocolate(count: Int)
    case jelly(count: Int, filling: Filling)
}

func eatDonuts(donuts: Donuts) {
    switch donuts {
    case let .sugar(count) where count < 5:
        print("🍩 Sugar donuts are so good.")
    case let .sugar(count) where count >= 5:
        print("🍩 Sugar donuts are so good but let's not go crazy.")
    case let .sugar(count) where count == 0:
        print("🍩 Why no donuts?!")
    case let .jelly(_, filling) where filling == .chocolate:
        print("🍩 Chocolate filling is so good! Great with coffee. ☕️")
    case let .jelly(count, _) where count > 0:
        print("🍩 Donuts with filling which is not chocolate is not for me.")
    case let .sprinkles(count) where count == 0:
        print("Why no donuts?!")
    case let .chocolate(count) where count == 0:
        print("Why no donuts?!")
    default:
        print("Mmmm... donuts.")
    }
}

eatDonuts(donuts: .sugar(count: 4))
eatDonuts(donuts: .sugar(count: 7))
eatDonuts(donuts: .sprinkles(count: 0))
eatDonuts(donuts: .chocolate(count: 2))
eatDonuts(donuts: .jelly(count: 1, filling: .chocolate))
eatDonuts(donuts: .jelly(count: 1, filling: .cream))