Tcl/Tk for Dummies®

Tcl/Tk and the Tcl plug-ins are the exciting new scripting system from Sun Microsystems, creator of the enormously popular Java programming language. With Tcl/Tk for Dummies^®, novice programmers can create simple, user-friendly applications in just a few minutes with a few lines of code.

Tcl/Tk combines the cross-platform flexibility and security of Java with the simplicity of languages like Visual Basic and HyperCard, with some Perl-like text handling thrown in. The Tk toolkit has been widely used by UNIX programmers to create Windows-based applications, and now it's available for Web-page creation. With this book at your side, you'll not only figure out how to pronounce it (tickle-t-k), but also how to use Tcl/Tk like a pro!

Inside, you'll find helpful advice on how to:

• Add Windows-style applications inside your Web pages
• Write cross-platform scripts that can run on Windows, Mac OS, and UNIX
• Create your own animations and games
• Improve your server's performance by moving CGI functions to the client side
• Program using a simple, forgiving language
• Understand more about how applications and computers work

• Introduction
• What Is Tcl/Tk and What's the Tcl/Tk Plug-In?
• Who Are You?
• What You Need
• What's on the CD?
• How to Use this Book
• How this book is organized
• Part I: What's Tcl/Tk?
• Part II: Language Reference
• Part III: Widget Science
• Part IV: Tclet Cookbook
• Part V: The Part of Tens
• Icons used in this book
• Now What?
1. What's Tcl/Tk?
1. Getting Started
• Identifying the Development Applications
• Tcl
• Tk
• Mini-applications
• Writing and drawing
• Finding Wish
• The source distribution
• Packagers (pre-compiled binaries)
• The Tcl/Tk plug-in
• Other cool stuff
• Taking Inventory
• Wish
• Tclsh
• Libraries
• Documentation
• Playing It Safe
• Security risks on the Internet
• Vandalism: protecting hard disks
• Crank calls: arbitrary connections
• Tcl Sources on the Internet
• Usenet news groups
• Web pages
2. Your Wish Is My Command
• Getting Your Wish
• Starting Wish
• Using Wish
• Clearing the board
• Your $2,000 desk calculator
• Strings and things
• Fine-tuning widgets
• A real program
• A little history
• Sourcing Files into Wish
• Quitting Wish
3. Creating a Tclet Source File
• Tackling Tclet Source Code with a Text Editor
• Using a preinstalled text editor
• Using Automatic Formatting Features
• Understanding color codes
• Coloring reserved words
• Using color to find problems with quote marks
• Balancing parentheses
• Following Formatting Conventions
• Using one command per line
• Breaking long code into several lines
• Putting multiple Tcl/Tk commands on a single line
• Adding comments to your code
• Indentation and grouping
• Managing brackets
• Indenting your Tcl/Tk code
• Adding horizontal space
4. Putting Tclets into Web Pages
• Using the <EMBED> Tag
• Specifying file paths
• Setting the tclet's size
• Setting the Tclet's MIME Type
• Passing Parameters to the Tclet
• Parameter-passing syntax
• Customizing a tclet with parameter information
• Making an inventory of the tclet's parameters
2. Language Reference
5. Basic Building Blocks: Commands and Variables
• What Are Commands?
• The anatomy of a command
• Command names
• Command options
• Command arguments
• Recognizing Tcl/Tk worlds
• Combinations not found in English (or any human language)
• Grouped and substituted material
• Constructing commands
• Reading the documentation
• What Are Variables
• Using scalars to store information
• Setting and retrieving scalars
• Changing data types
• Using associative arrays to store information
6. The Olde Switcheroo: Substitutions and Grouping
• Creating Substitutions
• Performing variable substitution by using the dollar sign
• Basic syntax
• Limits on variable substitution
• Creating command substitutions by using square brackets
• Grouping Text
• Grouping text by using curly braces
• Grouping text by using double quotes
• Protecting Special Characters with Backslashes
7. Flow Control: Conditionals and Loops
• Structuring Your Program
• Conditionals (Or, If I Only Had a Brain…)
• Making decisions with if
• The basic structure of the if command
• Evaluating the condition
• Designating the instructions
• Adding an else clause
• Adding an elseif clause
• Streamlining decisions with switch
• Around and Around and Around You Go: Looping Constructs
• Simple looping with for
• Basic construct of the for command
• The initialization statement
• The test statement
• The reinitalization statement
• The body of the loop
• Fancy looping with foreach
• The basic construct
• The name of the index variable
• The list
• Flexible looping with while
• The basic pattern
• The test statement
• the body of the loop
• Bailing out of a loop
• Changing your mind with break
• Skipping a loop with continue
8. I've Got a Little List!
• Making a List
• Moving Information
• Accessing individual elements
• Replacing Elements
• Inserting Elements
9. Strings 'n' Things
• Checking out Strings
• string length
• string index
• string first
• string last
• string range
• Comparing Strings
• string compare
• string match
• Creating and Parsing Strings
• format
• scan
10. Procedures and Functions
• Writing Your Own Commands
• Streamlining your program
• Reusing code throughout a tclet
• Reusing code in new tclets
• Building a proc Command
• Arguments for the procedure
• The body of the procedure
• The return command
• Using Global and Local Variables
• Local variables
• Global variables
3. Widget Science
11. What Is a Widget?
• Widget Basics
• A widget is a GUI component
• A widget is a window
• A widget is an OOP object
• Creating and Configuring Widgets
• The Widget Lineup
• Toplevels and frames
• Toplevels
• Frames
• Buttons
• Checkbuttons and radiobuttons
• Checkbuttons
• Radiobuttons
• Label, message, and text widgets
• Entry widgets
• Listboxes
• Scrollbars
• Scales
• Canvases
• Finding Documentation about Widget Options
• Event Bindings
• Displaying Widgets
12. Name, Rank, and Serial Number: Standard Widget Features
• Sprucing Up with Color
• background
• foreground
• Custom colors
• Tweaking Size
• The natural state
• Adjusting width
• Specifying height
• Adding Borders
• relief
• borderwidth
• Using Bitmaps
13. Binding
• The -command opttion
• Review of the -command option
• The bind Command
• Widget name
• Event name
• Command
14. Geometry Managers
• Making a game plan
• Choosing a geometry manager
• Mixing geometry managers
• Using frame widgets
• Adding Widgets with pack
• The -side option
• The -padx and -pady options
• The -ipadx and -ipady options
• The -anchor option
• The -fill option
• The -expand option
• The pack configure trick
• Adding Widgets with grid
• The -row and -column options
• Principle 1
• Principle 2
• The -rowspan and -columnspan options
• The -sticky option
4. Tclet Cookbook
15. Button, Button, Who's Got My Mutton?
• Button Features
• Executing Commands
• Making Choices
• Checkbuttons
• Radiobuttons
16. Label, Message, and Text Widgets
• Label Widgets
• Basic label options
• Special label options and commands
• Things to remember about labels
• Message Widgets
• Special message options and commands
• Things to remember about messages
• Text Widgets
• Default behavior of text widgets
• Special text options
• Character positions in a text widget
• Indexes
• Lines and character
• Coordinates
• Marks
• Tags
17. Canvases (or Painting with Pixels)
• Creating the Canvas
• Adding Stuff to the Canvas
• The coordinate system
• Rectangles and ovals
• Arcs
• Polygons
• Lines
• Ends and joints
• Arrowheads
• Curved lines
• Text
• Other kind of widgets
• Binding Stuff
• Moving Stuff
• Using Other Commands
18. Making Web Connections
• What Is HTTP?
• Things to Remember About the Web
• Connections can fail
• Servers can fail
• Security is an issue
• Waking up the Web Genie
• Connecting to a Web Page
• Understanding the basic game plan
• Sending the request
• The Status Array
• The -progress option
• The -command option
• Sending Information Back to a Server
19. Tcling the Browser
• Controlling the Browser
• Creating a frame-based HTML document
• Writing the HTML to contain the tclet
• Tclet command: package require Browser
• Initalizing the variables
• Creating the tclet's widgets
• Setting up the bindings
• Creating the showit procedure
• Writing the showsource procedure
• Writing the clearit procedure
• Talking to the Browser
• Getting browser information (navinfo.tcl)
• Writing alerts
• alarm.tcl
20. Building a Better Guestbook
• What Is a Guestbook?
• Why Use Tcl/Tk to Build a Guestbook?
• Before You Begin
• Providing a Better Layout
• Checking All Entries for Completeness
• Checking for HTML
• Filtering out Unwanted Words
• Bundling the Data
• Finishing the Guestbook
5. The Part if Tens
21. Almost Ten Differences Between Java and Tcl/Tk
• The Java Virtual Machine
• Compiling
• Security
• Complication
• Variables
• Dynamism
• Objects
• Multithreading
• Strings

• Appendix A: Regular Exprressions
• Globbing
• "Real" regular expressions
• Appendix B: About the CD-ROM

A decent introduction to the language(s).