TCL, Sun Microsystems Inc’s tool command scripting language which has been somewhat overshadowed by Java in the last few years, has been given a new lease of life by being combined with Java. Sun is releasing two new flavors of the product, currently in alpha versions. TCLBlend enables the Java virtual machine to be incorporated within TCL applications. And JACL – pronounced jackal – is a rewrite of the TCL interpreter in Java. TCL, originally written by John Ousterhout at the university of California at Berkeley, and now developed under him at a team at Sun Laboratories, the Research arm of Sun Microsystems, continues to attract a wide following, with something like a million developers using it worldwide. The language doesn’t have the official sanction of Sun Microsystems itself, which has instead geared its marketing machine around an alternative, JavaScript, originally sourced from Netscape Communications Corp.
All-round glue
The Sun Laboratories people claim that JavaScript is too focused on web browser and HTML tasks, and that TCL makes a better all- round glue language, for extending and connecting up existing components and applications written in C, C++ and Java. Such glue languages – others include Perl and Microsoft Corp’s Visual Basic – are typically typeless languages and interpreted rather than compiled, making them more flexible and easier and faster to program in than systems programming languages such as C, C++ and Java. TCLBlend is an extension of TCL that incorporates the Java Virtual Machine, so that Java classes can be invoked from TCL, and TCL scripts invoked from Java. It opens up the use of existing Java classes for TCL programmers, and enables TCL test scripts to be written as test Java classes. It can also help with the process of migrating to Java, by acting as a glue between Java classes and legacy C and C++ code. JACL is a new TCL interpreter written in Java and based on research work started at Cornell University. It enables TCL to be used in 100% pure Java environments, for such applications as web browsers for use on network computers. It’s a logical extension of a migration strategy using TCLBlend. Sun Labs says it intends to complete the implementation of JCAL, and then inject the technology into product groups at Sun itself. It’s by no means clear if it will be taken up. But Sun Labs’ deputy director, Russ Brown, says he would be happy to see the research project go on in perpetuity at the Labs if it doesn’t make it into the mainstream of Sun strategy, because, he says, it’s useful work and who else would do it if we didn’t?
