Many of the following are explained in more detail in Tcl/Tk for Programmers.
scrollable WIDGET_NAME WIDGET_TYPE ?TWO_WAY?where WIDGET_NAME is the name of the widget into which the scrollable widget should be packed (a frame or a toplevel widget), WIDGET_TYPE is text or listbox, and ?TWO_WAY? should be 1 if a horizontal as well as a vertical scrollbar is desired. The effect is to create a text or listbox widget with a vertical scrollbar (or with two scrollbars) and to return the name of this widget. You can use the returned name to re-configure the text or listbox widget to the way you want it to look.
lprune ?-not? LIST GLOB_PATTERNand lprune will return a sublist of LIST consisting of those elements that match (or don't match) the pattern GLOB_PATTERN. Use the -not switch to obtain elements which don't match. If LIST begins with "-" and "-not" isn't wanted, use "--" in its place.
One implementation uses the Tcl_Obj data type that was introduced with the C library for version 8.0 of Tcl. The other implementation works with earlier versions of Tcl. Compare the two for some idea of how programming with Tcl_Obj works.