The hush widget classes

The hush widget class library encapsulates the standard Tk widgets. In addition, a hypertext widget is offered. The widget classes are organized as a tree, with the class widget at the root. Each concrete widget class offers the functionality supported by the (abstract) widget class and may in addition define functions specific to the particular widget class. The member functions for a widget class have usually a straightforward correspondence with the command interface defined by the Tcl/Tk toolkit. See [Ousterhout94] for the most recent description. Each function listed in the class interface is public unless it is explicitly indicated as protected. The interface descriptions start with the pseudo-keyword interface. This is merely done to avoid the explicit indication of public for both the ancestor and the member functions of the class. Each widget class specifies two constructors, one with only a path and one which allows both for a widget and a path. In the latter case, the actual path consists of the concatenation of the path of the widget and the path specified by the string parameter. For the concrete widget classes, no widget will be created when the options parameter is zero. This convention is adopted to allow composite widgets to inherit from the standard widgets, yet define their own components. In addition, each widget class has a destructor, which is omitted for brevity. The destructor may be used to reclaim the storage for a widget object. To remove a widget from the screen, the function

widget::destroy must be used.