\documentclass{article}
\usepackage[margin=1in]{geometry}
\usepackage{mathpazo}
\usepackage{color}

\SWVweaveOpts{
  codefmt="frame=single", prompt="", 
  beforeout="\begin{quote}\color{blue}",
  afterout="\end{quote}"
}

\begin{document}
\section*{Expressions in StatWeave}

One subtlety of StatWeave is that you cannot embed an expression
until a code chunk in that language is encountered.  The way to work around
it is to insert a blank code chunk.
\begin{SWVcode}
The \texttt{ChickWeight} data is one of the standard datasets in R.
\begin{Rcode}{!echo}
# Nothing here
\end{Rcode}
It has \Rexpr{nrow(ChickWeight)} observations.
\begin{Rcode}{fig, scale=.5}
summary(ChickWeight)
plot(weight ~ Time, data=ChickWeight)
\end{Rcode}

From the plot, you can tell that the chicks grow at different rates.
\end{SWVcode}
Currently, a code chunk with no code at all causes an error.
The comment line in the above example was needed.  Maybe this will 
get fixed soon.
\end{document}