The R Language Definition manual should document comments. I think this should go after section 10.1 "The Parsing Process" and before 10.2 "Tokens". Here's some draft text. @node Comments, Tokens, The parsing process, Parser @comment node-name, next, previous, up @section Comments Comments in R are ignored by the parser. Any text from a \# character to the end of the line is taken to be a comment. For example, @smallexample
x <- 1 # This is a comment
@smallexample