An Acronym for Tool Command Language.

It is a scripting language embedded in many applications, much like Elisp is used in Emacs and VisualBasic is in many MicrosoftWindows applications. (This does not mean these languages have anything in common; actually they're about as far apart from each other as imaginably possible.)

Tcl is available on all Unix-like platforms, as well as on MicrosoftWindows. It is almost always combined with the Tk ToolKit. This makes it a good choice for portable GUI scripting. There is also a standalone interpreter, but it never achieved much popularity.

The language itself is limited and does not accomodate the needs of large, complex codebases. It was designed for easy extensibility and embeddability, intended to serve as a universal scripting interface to compiled libraries and applications containing the complexity and providing a simple API. The Tk ToolKit has remained the only significant success for this model. In practice, more capable dynamic languages like Perl, Python and Ruby that are designed to carry the complexity of a large codebase without the need for foreign libraries proved more popular at the one end, while fully scriptable applications never caught on at the other end. With Tk's popularity long since dwindling, giving way to GTK and Qt, so does the prominence of Tcl. Most people would consider it obsolete, though as with any technology (particularly in the OpenSource world), it has found a small following of supporters and enthusiasts who continue to evolve it. There is also still a moderate but significant amount of legacy TclTk code around.

See also:

• The Tcl community is working on the official Tcl Tutorial
• Tcl Developer Xchange
• The Tcler's wiki, a very useful resource on TCL.
• The Tcl newsgroup
• Tclwise, a partially online book about TCL that might be a little difficult for newcomers to understand
• tclsh(1)
• tclsh8.3(1)
• wish(1)
• wish8.3(1)

CategoryProgrammingLanguages, CategoryVeryHighLevelProgrammingLanguages