anchor.diff:    /// Get or set the angle accessor.
     angle([angle = undefined]) {
       var args = [];
  -    if (angle != undefined) {
  +    if (angle is Function) {
  +      args.add(func3VarArgs(angle));
  +    } else if (angle != undefined) {
         args.add(angle);
       }
       var retval = _proxy.callMethod('angle', args);
  
positive.code:   /// Control whether the line is defined at a given point.
    defined([defined = undefined]) {
      var args = [];
      if (defined != undefined) {
        args.add(defined);
      }
      var retval = _proxy.callMethod('defined', args);
  
negative.code:   /// Get or set the radius accessor.
    radius([radius = undefined]) {
      var args = [];
      if (radius is Function) {
        args.add(func3VarArgs(radius));
      } else if (radius != undefined) {
        args.add(radius);
      }
      var retval = _proxy.callMethod('radius', args);
  