gistfile1.txt

let json = [{
    name: "Klaas Pieter Annema",
    age: 28
  }, // Compiler infers Integer type for age
  {
    name: "Chris Eidhof",
    age: "Unknown"
  } // Compiler infers String type for age
];


struct Person {
  // No types
  var name
  var age
  
  init(untyped_dictionary) {
    self.name = untyped_dictionary["name"]
    self.age = untyped_dictionary["age"]
  }
}

// Some magical parsing code
untyped_array = parse(json);
let person1 = new Person(untyped_array[0])
let person2 = new Person(untyped_array[1])

person1.age // type is Integer
person2.age // type is String? (question mark)