Please look in the recent archives of this list: this was raised by Tony 
Rossini.
if(FALSE) {
}
already works.
On Mon, 14 Feb 2005, Gorjanc Gregor wrote:
> Hello!
>
> I found a wish for multilne comments under wishlist-fullfilled.
>
>
http://r-bugs.biostat.ku.dk/cgi-bin/R/wishlst-fulfilled?id=7261;expression=NA;user=guest
>
> Is this really fullfilled? Where, in R 2.1.0? I was not able to
> find any "announcements" or talks about that on mailing list
> or NEWS files.
>
> --
> Lep pozdrav / With regards,
>    Gregor GORJANC
>
> ---------------------------------------------------------------
> University of Ljubljana
> Biotechnical Faculty       URI: http://www.bfro.uni-lj.si
> Zootechnical Department    email: gregor.gorjanc <at> bfro.uni-lj.si
> Groblje 3                  tel: +386 (0)1 72 17 861
> SI-1230 Domzale            fax: +386 (0)1 72 17 888
> Slovenia
>
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>
>
-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595