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
Credits
About the Author
Acknowledgment
About the Reviewers
www.PacktPub.com
Preface

Combining pack and grid


It is not possible to combine pack and grid within the same container. If you attempt this the geometry managers will both attempt to control the screen geometry resulting in the screen failing to load. If you choose to combine the two, you may use pack to display a container (for example, a frame), which then utilizes the grid command to place the widgets within a grid located within the frame.

How to do it…

In the following example, we will create a frame and load it using the pack command. We will then arrange several widgets using the grid command identical to the previous example whose parent is the frame. Enter the following commands:

1 % frame .f borderwidth 3 relief raised
.f
2 % entry .f.e -width 10
.f.e
3 % label .f.1 -text ONE
.f.1
4 % label .2 -text TWO
.f.2
5 % label .f.3 -text THREE
.f.3
6 % button .f.b -text Exit -command exit
.f.b
7 % pack .f
8 % grid .f.e -row 0 -column 2
9 % grid .f.1 -row 1 -column 0
10 % grid .f.2 -row 1 -column 1
11 % grid .f.3...