The following code fragment shows the general structure of a mega-widget.

class  className  {
    inherit itk::Widget        #  or  itk::Toplevel
    constructor {args} {
        itk_option define  optName  {...}
        itk_component add  compName  {...}
        pack $itk_component(compName)  ...
        eval itk_initialize $args
    }
    public method  methodName ...
    protected method  methodName  ...
    private variable  varName ...
}
usual  className  {
    ...
}