koher

val a: Int = 999
val b: Int? = a
val c: Int? = a
println(b === c) // false

koher

extension CountableRange {
    public func contains(_ range: CountableRange<Bound>) -> Bool {
        return lowerBound <= range.lowerBound && range.upperBound <= upperBound
    }

    public func contains(_ range: CountableClosedRange<Bound>) -> Bool {
        return lowerBound <= range.lowerBound && range.upperBound < upperBound
    }

    public func contains(_ range: Range<Bound>) -> Bool {

koher

open class Animal
class Cat: Animal()

class Box<out Value> ( // `out` for covariance
	val value: Value
)

fun main(args: Array<String>) {
    val catBox: Box<Cat> = Box(Cat())
    val animalBox: Box<Animal> = catBox // OK

koher

class Animal {}
class Cat: Animal {}

let cats: Array<Cat> = [Cat()]
let animals: Array<Animal> = cats // OK

let cat: Optional<Cat> = .some(Cat())
let animal: Optional<Animal> = cat // OK

struct Box<Value> {

koher

// Argo
struct User {
  let id: Int
  let name: String
  let email: String?
  let role: Role
  let companyName: String
  let friends: [User]
}

koher

eachPair without AnySequence

extension Sequence where Self.SubSequence: Sequence {
  func eachPair() -> Zip2Sequence<Self, Self.SubSequence> {
    return zip(self, self.dropFirst())
  }
}

(1...10).eachPair().forEach { print($0) }

koher

SwiftScript Translation Catalog (Draft)

This is a catalog of translations by SwiftScript, a transpiler from Swift to JavaScript, for a hackathon. It supports only a subset of Swift and has some incompatibilities.

Supporting Library

SwiftScript tries to translate Swift codes to JS codes using builtin JS APIs. However some needs a supporting library to simulate behaviors of Swift. A typical example is ?..

If

koher

throws : async = try : await = catch : wait = rethrows : reasync = Result<T> : Promise<T>

throws : async = try : await

// Asynchronous selection by an action sheet
func actionSheet(itemes: [String]) async -> Int { ... }

// `await` must be in an `async` function
func foo() async {

koher

public class GenericReturnType {
  public static void main(String[] args) {
    // 引数の型は `Object` なので戻り値から型パラメータが推論される
    Integer n = id(42);
    String s = id("xyz");
    
    System.out.println(n);
    System.out.println(s);
  }
  

koher

func foo() -> Int { return 2 }
func foo() -> Float { return 3.0 }

let a: Int = foo()
let b: Float = foo()

print(a) // 2
print(b) // 3.0