Source code documentation generator tool.
Doxygen is a documentation system for C++, C, Java, Objective-C, Python, IDL (Corba and Microsoft flavors) and to some extent PHP, C#, and D.
http://www.stack.nl/~dimitri/doxygen/
Doxygen does not support Tcl directly but is possible to write a filter that convert the Tcl source code in to something similar to C++. Doxygen can call this filter when it is needed.
George Petasis: There is a small flex tool than act as a doxygen filter, to generate documentation with doxygen from tcl files. It can be found at [L1 ]
A little doxygen converter is another one. (pmarin: Actually It implements a subset of doxygen.)
See doxygen+tcl for a patch to include Tcl support in doxygen.