[R] How to comment out entire code parts in Sweave files

[Werner W.]

Hi,

I am wondering if there is any convenient way to comment out an entire region of 
a Sweave file which comprises R and Latex code. Currently I'm doing it for the R 
and Latex parts separately or transfer the unwanted part into a different file. 
But both are not great solutions. (I am doing this when updating old files and 
debugging)

Is there a way to do this with an equivalent of \iffalse \fi or is there some 
"stop" command after which Sweave just stops processing?

Thanks a lot for any suggestions.
  Werner