I believe that CodeRay should consider making a Tcl as one of it's supported language.
I have attached a basic Tcl scanner. - @et

The scanners that are included in the distribution all fulfill the basic requirements. You can take the Python scanner and tests as an example. Also, the PLEAC examples are always a good source. Together, the test codes should cover all syntactic features and details of the language; that's simple for Python, and near impossible for Perl. I guess TCL is somewhere in between. - @korny

Have this about 50% done, been busy with some other stuff at the moment. The pleac data is showing me a lot about tcl that I didn't know you could even do. I'm also adding support for tk and itcl since they pretty much go hand in hand with tcl. - @et

The code Eric Thomas posted to Redmine is on a branch https://github.com/rubychan/coderay/compare/tcl-scanner

From Redmine: http://odd-eyed-code.org/issues/220