Sexpr problem

Hi.

I am having difficulty  making \Sexpr work as desired.
  Specifically, the pdf and the text  versions of the help system
differ, and I can't reproduce the example on page 63 of
the R Journal article by  Murdoch and Urbanek (Vol 1/2,
December 2009).

Is there an example package that I could examine for Best Practice?

We use \Sexpr in only a couple of places currently:  in the NEWS.Rd 
files (which are treated differently than other .Rd files), and in the 
tools package where it is illustrated (see ?tools::Rd2HTML; the last few 
lines of the note are generated using \Sexpr).

If you put together a simple .Rd file that shows the difference you're 
seeing, I'll take a look.

Duncan Murdoch