Book Image

Tcl/Tk 8.5 Programming Cookbook

Book Image

Tcl/Tk 8.5 Programming Cookbook

Overview of this book

With Tcl/Tk, you can create full-featured cross-platform applications in a simple and easy-to-understand way without any expensive development package; the only tools required are a simple text editor and your imagination. This practical cookbook will help you to efficiently interact with editors, debuggers, and shell type interactive programs using Tcl/Tk 8. This cookbook will comprehensively guide you through practical implementation of Tcl/Tk 8.5 commands and tools. This book will take you through all the steps needed to become a productive programmer in Tcl/Tk 8. Right from guiding you through the basics to creating a stand-alone application, it provides complete explanation of all the steps along with handy tips and tricks. The book begins with an introduction to the Tcl shell, syntax, variables, and programming best practices in the language. It then explores procedures and the flow of events with control constructs followed by advanced error trapping and recovery. From Chapter 4, a detailed study of string expressions and handling enables you to handle various string functions and use lists to expand the string functionality. The book then discusses in-depth the Tcl Dictionary and how to utilize it to store and retrieve data. File operations and Tk GUI handling are covered extensively along with a developing a real-world address book application to practice the concepts learned.
Table of Contents (20 chapters)
Tcl/Tk 8.5 Programming Cookbook
About the Author
About the Reviewers

Displaying the directory dialog

The tk_chooseDirectory command displays a dialog window that allows the end user to select a directory, as the name implies. The return value is the absolute directory path selected or an empty string (if the Cancel button is clicked).

The syntax is as follows:

tk_chooseDirectory option value …

The tk_chooseDirectory command accepts one or more option value pairs as detailed below. If no option value pairs are provided, the command will display the default values for the dialog.



-initialdir directory

Sets the initial directory to display. If not set, the current working directory will be displayed.

-mustexist boolean

Specifies if the user may specify a non-existing directory.

-parent window

Specifies the parent of the dialog. The dialog is displayed on top of the parent.

-title string

Sets the text to be displayed in the dialog title bar.

How to do it…

In the following example, we will display a message box and assign...