问iOS：“GPX.Waypoint”不符合“MKAnnotation”协议

EN

import MapKit

extension GPX.Waypoint: MKAnnotation
{
    var cooridnate:CLLocationCoordinate2D {
        return CLLocationCoordinate2D(latitude: latitude, longitude: longitude)
    }

    var title:String! { return name }

    var subtitle:String! { return info }
}

class Waypoint: Entry, Printable
    {
        var latitude: Double
        var longitude: Double

        init(latitude: Double, longitude: Double) {
            self.latitude = latitude
            self.longitude = longitude
            super.init()
        }

        var info: String? {
            set { attributes["desc"] = newValue }
            get { return attributes["desc"] }
        }
        lazy var date: NSDate? = self.attributes["time"]?.asGpxDate

        override var description: String {
            return " ".join(["lat=\(latitude)", "lon=\(longitude)", super.description])
        }
    }

protocol MKAnnotation : NSObjectProtocol {

    // Center latitude and longitude of the annotation view.
    // The implementation of this property must be KVO compliant.
    var coordinate: CLLocationCoordinate2D { get }

    // Title and subtitle for use by selection UI.
    optional var title: String! { get }
    optional var subtitle: String! { get }
}