json.swift

enum JSON {
    case StringType(String)

    enum Number {
        case IntType(Int)
        case FloatType(Float)
    }
    case NumberType(Number)

    case BoolType(Bool)

    indirect case ObjectType([String: JSON])

    indirect case ArrayType([JSON])

    case Null

    var int: Int? {
        guard case .NumberType(let num) = self else {
            return nil
        }
        guard case .IntType(let val) = num else {
            return nil
        }
        return val
    }

    var string: String? {
        guard case .StringType(let val) = self else {
            return nil
        }
        return val
    }
}

extension JSON: StringLiteralConvertible {
    typealias ExtendedGraphemeClusterLiteralType = StringLiteralType
    typealias UnicodeScalarLiteralType = StringLiteralType

    init(unicodeScalarLiteral value: UnicodeScalarLiteralType) {
        self = .StringType("\(value)")
    }

    init(extendedGraphemeClusterLiteral value: ExtendedGraphemeClusterLiteralType) {
        self = .StringType(value)
    }

    init(stringLiteral value: StringLiteralType) {
        self = .StringType(value)
    }
}

let j: JSON = "HELLO"
j.string


let a = JSON.NumberType(.IntType(5))
let i = a.int