     var Z : String { get { return self + "Z" } }
 }
 
-public extension NSMutableString {
+@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 } }

    var underscore    : String { get { return self + "_" } }
}

public extension NSMutableString {
    var space         : NSMutableString { get { append(" "); return self } }
    var point         : NSMutableString { get { append("."); return self } }
    var dash          : NSMutableString { get { append("-"); return self } }

    var dot         : String { get { return point } }
}

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