This way I hope I can learn to document my code better :)
The following page helped me install doxymacs, emacs plug-in for doxygen.
(Actually what I had to do was just to type apt-get install doxymacs)
Then I confronted the problem of not displaying my e-mail address correctly.
I think this is because I didn't configure my Ubuntu properly, but at least I could find that
(setq user-mail-address "email@example.com")
will set my user-mail-address variable, and would propagate to doxymacs-user-mail-address.
As a statistics Ph.D student, I felt obliged to know how to document R codes (although R is not my favorite language for scientific computation). The solution is to try Roxygen in the following project page:
It's good that ESS (Emacs Speaks Statistics) supports Roxygen! Actually I've never done anything ambitious in R (just homework problems), but I would definitely try to use Roxygen when the appropriate time comes!