Sun reverses course on Tcl products Report from the Boston Tcl/tk Workshop: Tcl and Java in bed together By Cameron Laird and Kathryn Soraiz

August  1997

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Speaking recently at Usenix's fifth annual Tcl/TK Workshop in Boston, Sun Distinguished Engineer and Tcl inventor John Ousterhout told the audience that SunScript would no longer be a profit center.

In mid-June, SunScript quoted licenses of several hundred dollars and lower for such products as the SpecTcl development tool and the Tcl Plug-in (see Resources, below). Though they're still identified as "Products" in SunScript Web pages which offer to "download a free evaluation copy," the business plan has changed. "We're giving it away. It's all free," said Ousterhout, to audience applause, "including the source code."

Speaking after the conference, Ousterhout explained the shift. "Rather than devote resources to the commercial aspects, we're going to do really exciting things integrating Tcl with Java in a dynamic way," he said.

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Java integration
Ousterhout created Tcl at the end of the 1980s to facilitate his own research in computer-assisted design applications at the University of California at Berkeley. Tcl has had a tradition of pragmatic achievement ever since, and the Boston Workshop certainly sounded this theme. The event was unmistakably run by and for engineers, even though this was the first year without an "entrance exam" as part of the registration application. Headliners puttered with T-1s past midnight, books, and T-shirts were the favored door prizes. Even people with products to sell seemed happiest giving them away.

The sessions themselves often told variations on a single tale: an individual or tiny team overcomes indifference or even hostility from its larger organization to rush through development of a Tcl-based application that eventually becomes an indispensable asset.

To date, Tcl's record is impressive. Among other things, it manages NBC's (the U.S. television network) control room, controls astronomical equipment at prestigious observatories, performs as part of the Pathfinder equipment now roaming Mars, "glues" together the code for several of the most well-known WWW search engines, including Alta Vista and DejaNews.

Tcl: Language or glue?
The word "glue" has a special resonance within the Tcl community. While Tcl is a full-fledged language in its own right, its historical origins and expected future revolve around its nature as "glue," or "scripting." Tcl is good for "extending" and "embedding," that is, combining existing facilities, written in other languages, in a way that is very easy, even for non-experts, to use and re-use. These are "extensions." Extensions embed specialized facilities -- Oracle or other DBMSs, GUIs, system or network management routines, process control hooks, video manipulation -- in a framework that exposes them through the easy-to-learn Tcl syntax.

Sun hired Ousterhout and a small team of developers in May 1994 to nurture the technology. Since then, they've had to balance the forces pulling Tcl in different directions. Should development resources go to upgrading the "core" capabilities of the language itself (standalone Tcl) or to simplifying its ease of integration with other components (Tcl as glue)? What's the trade-off between portability and power? Ousterhout has managed these creative tensions for a decade now, but the stakes have been raised following the birth of a certain 800-pound gorilla called Java.

Ousterhout's position on Java has been consistent: Java is a good language for developing "components," but it's too abstruse for casual users, or even efficient prototyping by specialists. That's a job for Tcl: to script Java-based components into working applications.

The Workshop's keynote address reinforced this. Brian Kernighan of Bell Laboratories, revered for his contributions to C and Unix, described his recent experiments in implementing real Bell requirements in Tcl, Visual Basic, and Java. Though he cited an example from wireless networking that highlighted Tcl's best practical features -- its uniquely powerful canvas and text widgets, convenient access to the Unix operating system command line, and so on -- Kernighan emphasized philosophical virtues. For him, Tcl is simple, robust, intellectually manageable, and mature. It's not "dogmatic," he said; it permits a variety of paradigms to be coded naturally. Dynamism and experimentation are essential in development of superior user interfaces, and Tcl lends itself to these far better than the cumbersome VB and Java approaches.

The future: taking over the world or fading into oblivion?
The dialectic between specific engineering details and overarching principles continued through the week. Participants said they found Tcl indispensable for a couple of reasons: it's the one humanly-comprehensible way to access the Windows Registry, and also because its Expect extension is (by orders of magnitude) more portable and reliable than any other existing abstraction of pseudo-terminals. Others find comfort in the craft which makes Tcl available and efficient for Unix, Windows, MacOS, OpenVMS, and a variety of real-time operating systems.

The year-ahead plan Ousterhout presented incorporates both functional advances for version 8.1 -- Unicode support, re-write of common widgets to exploit the speed-ups of version 8.0 -- and broader themes of integration with Java for version 8.2.

The final day's panel session was quite self-consciously titled, "Tcl/Tk--Taking Over the World or Fading Into Oblivion?" Audience participants testified to their conviction that Tcl is the right tool for many, many applications, but that institutional resistance continues to constrain its use. "There are tens of thousands of Tcl-based applications in use," said Ousterhout, but one engineer from the audience reported, "People keep asking me, `Why don't you use a real language?'" While the luminaries of the Tcl galaxy generated a few tentative marketing possibilities on improving acceptance -- an industry consortium, advertising, better coverage in the Windows press -- the direction SunScript will take for the next year is largely set. The team will return to their labs, improve details, and, most dramatically, integrate Tcl with Java in three ways:

• Expose Java-coded components as objects accessible from within Tcl
• Improve the ease with which Java applications can embed Tcl
• Re-implement Tcl in Java

The audience voted for a West Coast venue, perhaps San Diego, for 1998's Workshop. We'll know by then whether the computing world at large regards Tcl as an essential partner to Java, or just another obscure jewel of language implementation.

Cameron Laird and Kathryn Soraiz manage their own software consultancy, Network Engineered Solutions, from the Houston, TX area. Reach Cameron at cameron.laird@sunworld.com.

If you have technical problems with this magazine, contact webmaster@sunworld.com

URL: http://www.sunworld.com/swol-08-1997/swol-08-sunscript.html

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Resources

• SunScript Home Page
  http://www.sunscript.com
• June 1997 SunWorld news story, "New Tcl scripting product group spun out of Sun Labs"
  http://www.sun.com/sunworldonline/swol-06-1997/swol-06-sunscript.html
• Index to the Fifth Tcl/Tk Workshop
  http://starbase.neosoft.com/~claird/comp.lang.tcl/workshop.html
• Larry Virden's comp.lang.tcl FAQ launcher
  http://www.teraform.com/%7Elvirden/tcl-faq/

About the author
Cameron Laird and Kathryn Soraiz manage their own software consultancy, Network Engineered Solutions, from the Houston, TX area. Reach Cameron at cameron.laird@sunworld.com.

If you have technical problems with this magazine, contact webmaster@sunworld.com

URL: http://www.sunworld.com/swol-08-1997/swol-08-sunscript.html
Last modified: