In Swift, does Int have a hidden initializer that takes a String?

Question

I tried looking at the Swift API for Int, and I\'m still not sure why this works:

var foo = Int(\"100\")

I see the following initializers i

Answer 1

There is a

extension Int {
    /// Construct from an ASCII representation in the given `radix`.
    ///
    /// If `text` does not match the regular expression
    /// "[+-][0-9a-zA-Z]+", or the value it denotes in the given `radix`
    /// is not representable, the result is `nil`.
    public init?(_ text: String, radix: Int = default)
}

extension method taking a string and an optional radix (which is 10 by default):

var foo = Int("100") // Optional(100)
var bar = Int("100", radix: 2) // Optional(4)
var baz = Int("44", radix: 3) // nil

How could one find that? Using the "trick" from "Jump to definition" for methods without external parameter names, write the equivalent code

var foo = Int.init("100")
//            ^^^^

and then cmd-click on init in Xcode :)