sample.txt

var dict = ["a": "Apple",                   // set up the Dictionary
            "b": "Banana",
            "c": "Cherry"]
let bananaIndex = dict.indexForKey("b")!    // retrieve an index
println(dict[bananaIndex])                  // subscript via DictionaryIndex<String, String>
> (b, Banana)
println(dict["c"])                          // subscript via String key
> Optional("Cherry")

let set: Set = ["Apple", "Banana", "Cherry"]  // set up the Set
let start: Int = set.startIndex
println(set[start])
> Cherry

println(set["Apple"])
error: type 'Index' does not conform to protocol 'StringLiteralConvertible'

/*
Checked equality (true) on equal big sets in 0.923960983753204
Checked equality (false) on different-size big sets in 2.98023223876953e-06
Checked equality (false) on same-size unequal big sets in 0.908538997173309
*/