The class hierarchy looks complicated, but in actual practice,
application programmers almost always refer to the classes at
the very bottom of the hierarchy. To make use of this reference
material, there will be times when you will need to know how to
read short passages of Tk and how to identify the various parts
of a Tk command. (See section 16.1.4 for the Tkinter equivalents
of what's below.) Tk scripts are Tcl programs. Like all Tcl
programs, Tk scripts are just lists of tokens separated by
spaces. A Tk widget is just its class, the options that help
configure it, and the actions that make it do useful things. To
make a widget in Tk, the command is always of the form:
classCommand newPathname options .(period) and children are
delimited by more periods. For example,
.myApp.controlPanel.okButtonmight be the name of a widget.
button .fred -fg red -text "hi there" ^ ^
\_____________________/ | | | class new options command widget
(-opt val -opt val ...) Once created, the pathname to the widget
becomes a new