Exepting member declaration

Question

I tried to use JavaCV with Kotlin, but have a problem in that code

import org.bytedeco.javacv.OpenCVFrameGrabber
import org.bytedeco.javacv.CanvasFrame
import org.bytedeco.javacv.Frame

class Vision {

    var grabber: OpenCVFrameGrabber = OpenCVFrameGrabber(0)
    grabber.start()

    var frame: Frame = grabber.grab()

    var canvasFrame: CanvasFrame = CanvasFrame("Test Title")
    canvasFrame.setCanvasSize( frame.imageWidth, frame.imageHeight )

    while (canvasFrame.isVisible() && (frame = grabber.grab()) != null) = this.canvasFrame.showImage(frame)

}

a grabber.start() string with canvasFrame. is showing a mistake "Expecting member declaration"

Can u help me?