The CsLex source is now posted on GitHub.
Many years ago (1999), I wrote a lexer in C#, based on the Java JLex parser. At that time we did not have a Visual Studio with C# compiler support, so I also had to create an Emacs C# mode, in order to help me while porting the JLex parser to C#.
It was an interesting experiment, and helped me personally understand C# well at the time. I actually used the parser to create a Pgn2Xml converter.
I’ve recently been resurrecting some of my older sample programs, in the hopes that they might be helpful to someone, as well as training me in the use of Jekyll for blogging about various technologies.