Programming Python, 3rd Edition

Python/Tkinter for Tcl/Tk Converts

At the start of this chapter, I mentioned that Tkinter is Python’s interface to the Tk GUI library, originally written for the Tcl language. To help readers migrating from Tcl to Python and to summarize some of the main topics we met in this chapter, this section contrasts Python’s Tk interface with Tcl’s. This mapping also helps make Tk references written for other languages more useful to Python developers.

In general terms, Tcl’s command-string view of the world differs widely from Python’s object-based approach to programming. In terms of Tk programming, though, the syntactic differences are fairly small. Here are some of the main distinctions in Python’s Tkinter interface:

Creation

Widgets are created as class instance objects by calling a widget class.

Masters (parents)

Parents are previously created objects that are passed to widget-class constructors.

Widget options

Options are constructor or config keyword arguments or indexed keys.

Operations

Widget operations (actions) become Tkinter widget class object methods.

Callbacks

Callback handlers are any callable objects: function, method, lambda, and so on.

Extension

Widgets are extended using Python class inheritance mechanisms.

Composition

Interfaces are constructed by attaching objects, not by concatenating names.

Linked variables (next chapter)

Variables associated with widgets are Tkinter class objects with methods.

In Python, widget creation commands (e.g., button) are Python class names that start ...