[R] Sweave question: prevent expansion of unevaluated reused code chunk

[Seth Falcon]

"Kevin R. Coombes" <krc at mdacc.tmc.edu> writes:

> Hi,
>
> Consider the following (much simplified) Sweave example:
>
> --------------
>
> First, we set the value of $x$:
> <<chunk1,eval=FALSE>>=
> x <- 1
> @
>
> Then we set the value of $y$:
> <<chunk2,eval=FALSE>>=
> y <- 2
> @
>
> Thus, the overall algorithm has this structure:
> <<combined,eval=FALSE>>=
> <<chunk1>>
> <<chunk2>>
> @
>
> <<justDoIt,echo=FALSE>>=
> <<combined>>
> @
>
> ---------------
>
> I'd like to be able to do something like this, where the "combined" 
> chunk prints out in the final LaTeX document essentially verbatim.  In 
> particular, I want to see the "<<chunk1>>" unexpanded in that block, 
> since this gives me a nice conceptual overview of the algorithm. (Of 
> courser, this is more useful when chunk1 and chunk2 are much longer than 
> they are in this example....)
>
> Is there an option that allows me to get this behavior?

Maybe I'm not understanding what it is you want, but why not:

\begin{verbatim}
<<chunk1>>
<<chunk2>>
\end{verbatim}

What does putting this in an unevaluated chunk buy you?  The
<<chunkName>> markers are an internal detail of the document and so
must of the time these never appear in the rendered output.  Even in
your example, won't it be confusing that <<chunk1>> and <<chunk2>>
won't have appeared in labels earlier in the rendered document?

+ seth

-- 
Seth Falcon | Computational Biology | Fred Hutchinson Cancer Research Center
http://bioconductor.org