[R] How to use multi paragraph comment like /* and */ in cpp?

[Martin Maechler]

>>>>> "PS" == PO SU <rhelpmaillist at 163.com>
>>>>>     on Tue, 9 Sep 2014 10:49:32 +0800 writes:

    PS> Dear expeRts,    I find it's terrible  when  i want to
    PS> comment multi paragraph (e.g.  a 30 lines function) , i
    PS> have to comment each line with #,  is there any good way
    PS> to do that ?     I investgate it, but found no easy way,
    PS> may you help me ?

Even though I can easily mark such a block and use the general
emacs  comment key    M-;
to comment each of those lines,
I often prefer

 if(FALSE) {

   ...
   ...
   ...

 }

which in the case of a single function definition which is only
one R expression can even do without the braces  {, }
and hence very easily activated/deactivated.