     COMMENTS
          If the first non-blank character in a  command  is  #,  then
          everything  from the # up through the next newline character
          is treated as a comment  and  ignored.   When  comments  are
          embedded  inside  nested  commands  (e.g. fields enclosed in
          braces) they must  have  properly-matched  braces  (this  is
          necessary  because  when Tcl parses the top-level command it
          doesn't yet know that the nested field will  be  used  as  a
          command so it cannot process the nested comment character as
          a comment).
