     var dot         : String { get { return point } }
 }
 
-public extension NSMutableString {
+@objc public extension NSMutableString {
     var dot         : NSMutableString { get { return point } }
 }

    var _0 : String { get { return self + "0" } }
}

public extension NSMutableString {
    var _1 : NSMutableString { get { append("1"); return self } }
    var _2 : NSMutableString { get { append("2"); return self } }
    var _3 : NSMutableString { get { append("3"); return self } }

    var z : String { get { return self + "z" } }
}

@objc public extension NSMutableString {
    var a : NSMutableString { get { append("a"); return self } }
    var b : NSMutableString { get { append("b"); return self } }
    var c : NSMutableString { get { append("c"); return self } }
