Tcl and Tk Michael U. Ang

history and purpose

How it started originally intended to be a reusable command language. After implementing several such "quick-and- dirty" command languages and experiencing problems with each one, Then decided to concentrate on implementing a general-purpose, robust command language that could easily be integrated into new applications. Thus Tcl (Tool Command Language) was born.

How it started Tcl is used in combination with the Tk ("Tool Kit") library, a set of commands and procedures that make it relatively easy to program graphical user interfaces in Tcl.

What is Tcl? developed by John Ousterhout (OH-stir-howt) at UC Berkeley. Tcl stands for “tool command language” interpreted scripting language; most commonly used to build graphical interfaces in conjunction with Tk. everything is text

Cont… What is Tcl? Tcl programs are simply scripts consisting of Tcl commands that are processed by a Tcl interpreter at run time. example use of Tcl: to build a graphical interface that displays the output of a C command, and/or controls the parameters to the C command.

Cont… What is Tcl? The Tcl interpreter has been ported from UNIX to DOS, Windows, OS/2, NT, and Macintosh environments. The Tk toolkit has been ported from X Window to Windows and Macintosh.

What is Tk? A graphical toolkit that gives one access to many of the graphics primitives of the underlying windowing system, as well as providing access to many types of widgets, such as buttons, scrollbars, menus, and text boxes. a set of commands and procedures that make it relatively easy to program graphical user interfaces in Tcl. Tk defines Tcl commands that let you create and manipulate user interfaces.

What is wish? wish is an interpreter that one can use that: 1) interprets Tcl commands, and 2) interprets Tk commands. wish provides access to the combined functionality of Tcl/Tk.

Versions Tcl/Tk is the recent stable release version. released on July 22, 2003 Tcl/Tk 8.4 latest stable release of Tcl/Tk highly compatible with Tcl 8.3 through Tcl 8.1 introduces new core widgets, significant performance enhancements, numerous command enhancements and improved 64-bit integer and file system support

Tcl/Tk 8.3 compatible with Tcl 8.2 and Tcl 8.1 added many new features to Tk based on the Dash patch and Img patch previous stable release, 8.3.5, was released on Oct 18, 2002 Tcl/Tk 8.2 updated the build process to the new Tcl Extension Architecture. The new features are primarily at the C-level APIs to support new extensions. There are also new regular expression C APIs to support Expect. eliminated minor bugs left over from the 8.1 release Cont… Versions

Tcl/Tk 8.1 was a major overhaul of Tcl/Tk. new support for Unicode and internationalized applications adds thread-safety to the C implementation, and an all new regular expression package that adds Advanced Regular Expressions Tcl/Tk 8.0 one of the widely used release added an on-the-fly byte-code compiler added improved cross-platform look and feel; and a menubar facility and a platform-neutral font naming system last patch release was Cont… Versions

Looking forward Tcl/Tk 9.0 represents the next giant step for core development. Relatively few new features will be introduced in 9.0; instead, development will focus on rationalization and refactorization of the C API's and Tcl commands, and modularization of the core itself. 9.0 does not currently have a release date.

Important Features strengths & weaknesses

1. Easy to learn  Tcl/Tk is a very simple language. 2. Standard syntax  once users know Tcl, they will be able to issue commands easily to any Tcl-based application. 3. Graphical user interfaces  Tcl’s TK toolkit. 4. Cross-platform applications  the same Tcl script can run on any platform, hence it provides an excellent management and integration tool for mixed environments. Features

5. Rapid development  gets their job done faster.  Development is fast because of the rapid turnaround; there is no waiting for long compilations 6. Extensible applications/Embedable  easy to incorporate Tcl into an application  the Tcl interpreter (a library of C procedures) was designed to be embedded in a variety of applications. Cont… Features

7. Flexible integration  easy to coordinate existing components and applications so that they work together effectively. 8. BONUS: It's free!

Drawback As the application gets larger, Tcl/Tk code becomes more and more difficult to understand, maintain and extend.

Tcl Comparison Chart

FeaturesTclPerlPython Java Script Visual Basic Speed of useRapid development Flexible, rapid evolution Great regular expressions Breadth of functionality Easily extensible Embeddable Easy GUIs Internet and Web-enabled Enterprise usageCross platform Internationalization support Thread safe Database access

Sample Programs

This shows a Hello button on the Main window. When you click the button the console window will display the string "Hello World!" on the console. button command creates an instance.b button called.hello. -text string shows the button title. -command string is the command responsed to the button's action. pack command layouts the button on the window. Hello World pack [button.b -text "Hello" -command {puts "Hello World!"}]

Scollbar

Applications written in Perl

AOLserver is America Online's Open-Source web server. a multithreaded, Tcl-enabled web server used for large scale, dynamic web sites. AOL's Digital City US’s largest and most popular local city resource. uses a Tcl interpreter in each of the back-end host processes that provide services to Digital Citys visitors Every Web page in the Digital City network is generated by an embedded Tcl script.

Cisco’s ATS (Automated Test System) composed of several tools and libraries based on Tcl that provide support for writing and executing automated test scripts. Tcl is incorporated in the ATS interpreter to generate libraries that simplify the task of controlling remote devices from automated test scripts. Cygnus's Source-Navigator It extracts information from existing C, C++, Tcl, [incr Tcl], FORTRAN, Cobol, and assembly programs and uses this information to build project databases. Source-Navigator is developed in Tcl, with about 95% of the code in Tcl and the rest in C.

Url’s and Books

or -- Main site where you can find the distribution codes, manual pages and documentations, and other relevant informations regarding the Tcl/Tk product line Home Page for the Official Tcl/Tk Contributed Sources Archive!

-- provides the extra language support needed to build large Tcl/Tk applications. -- introduces the notion of objects, which act as building blocks for an application.

-- The industry-standard Tcl distribution for HP-UX, Linux, Solaris, and Windows. -- free System Requirements for Active Tcl Solaris :: sparc architecture only :: Minimum Solaris 2.6 HP-UX :: PA-RISC :: Minimum HP-UX 11 Windows Systems: :: x86 architecture only :: Win2K,ME or XP: No additional req :: WinNT 4.0, 98: Internet Explorer 5+ :: WinNT 4.0: Service Pack 5+ Linux Systems: :: IX-86 :: Minimum 2.0 kernel

Visual Tcl -- FREEWARE; currently available: Version 1.6.0b2 -- supports UNIX, Windows, Macintosh and AS written entirely in Tcl/Tk and generates pure Tcl/Tk code -- originally written by Stewart Allen, but development has been taken over by Christian Gavin and Damon Courtney

Books Tcl and the Tk Toolkit, by John K. Ousterhout (Addison-Wesley, April 1994) Practical Programming in Tcl and Tk (4 th ed), by Brent Welch, (Prentice Hall PTR, June 2003)

Cont… Books Tcl/Tk: A Developer's Guide (2 nd ed), by Clif Flynt (Morgan Kaufmann; May 2003 )

The End