interface to the Tk toolkit. The Tcl library has a C interface to

create and manage one or more instances of a Tcl interpreter, run Tcl

commands and scripts in those instances, and add custom commands

implemented in either Tcl or C. Tcl provides for an event queue, used

for I/O, timers, and by modules.

implemented in either Tcl or C. Each interpreter has an event queue,

and there are facilities to send events to it and process them.

Unlike Python, Tcl's execution model is designed around cooperative

multitasking, and Tkinter bridges this difference

(see `Threading model`_ for details).

Tk

Tk is a module that can be loaded into a Tcl interpreter instance. It adds