Swift public class with private var equality

main.swift

let t1 = TinkerObject(id:1)
let t2 = TinkerObject(id:2)

// this will work
print (t1==t2)

// this would be an error:
// 'TinkerObject' does not have a member named 'id'
// print(t1.id)

tinker.swift

public class TinkerObject : Equatable {
  private let id:Int
  init(id:Int) {
    self.id = id
  }
}

//
// note that this is OUTSIDE of your class impl to make it
// global, but INSIDE the same file to allow access to the
// private variable
//
public func ==(lhs: TinkerObject, rhs: TinkerObject) -> Bool {
  return lhs.id == rhs.id
}

Throw these in a directory and compile with swiftc *.swift