Rush is a language derived from Tcl and was presented at the 1993 Tcl/Tk Workshop and the 1994 Tcl/Tk Workshop. Here is more information: http://number-none.com/blow/papers/rush_tcl94.pdf
The abstract of the paper says:
Rush is a new language that looks and feels much like Tcl [?]; we offer a compiler that executes scripts a hundred times faster than Tcl 7.x, allowing programs to run at speeds close to their C-language counterparts. Rush incorporates many features from Tcl and contains new features. From Tcl, Rush acquires its syntax, everything is a string model, set of core commands and datatypes, scoping rules, C callout facility, and support for popular libraries, including Tk and Tcl-DP. New features in Rush include pass-by-reference, first class closures and production rules. A generalization of operator syntax allows users to code in either command-style or operator-style syntax; a converter program provides a translation between the two forms. We introduce the language as a set of changes to Tcl, with a focus on performance issues and discussion of new features.
Does anyone use this today (2005)??