\SweaveOpts{engine=R, keep.source=TRUE}
\setSinput{\normalsize}%{\small}
\setSoutput{\normalsize}%{\footnotesize}
<<preliminaries, echo=FALSE>>=
options(width = 64)# 70 for "default" \footnotesize of Soutput
@

\begin{frame}[fragile]{\useSourceTit}
  \begin{block}{Obi-Wan Kenobi \dots:}
    ``Use the source, Luke!''
  \end{block}


<<inst-fortunes, eval=FALSE>>=
install.packages("fortunes")
@
<<fortune_250>>=
fortune(250)
@
%% As Obi-Wan Kenobi may have said in Star Wars: "Use the source, Luke!"
%%    -- Barry Rowlingson (answering a question on the documentation of some implementation
%%       details)
%%       R-devel (January 2010)
\end{frame}
%% Reset to defaults in ./mmVignette.sty
\setSinput{\small}
\setSoutput{\footnotesize}