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 a pop-up menu

A pop-up menu is exactly as the name implies: a menu that appears arbitrarily. It is accessed via a user action (normally a mouse click). The menu is created as normally, but is accessed by binding to an event. The actual display of the menu is accomplished by the tk_popup command.

The syntax is as follows:

tk_popup name x y

How to do it…

In the following example, we will create a menu that contains an option to exit a window. Create the following text file and save it in your working path with the name my_popup.tcl:

# Load the TK Package
package require Tk
#Define our interface
wm geometry . 320x240
wm title . "Menu Example"
# Create a menu to exit our window
set File [menu .popup]
# Add the Exit entry
$File add command -label Exit -command exit
# Now we add a label to bind to
label .l -text "Click here to access your menu"
pack .l
# Now bind to the right mouse click
bind .l <3> {tk_popup .popup %X %Y}

Now launch the program by invoking the following command...