Does anyone use Sweave (RweaveLatex) option "expand=FALSE"?

I picked the example from segmenting chromosomes for a reason. ?I have a
fair chunk of code that deals with not quite exceeding the amount of RAM
available in the machine sitting on my desktop. ?If I use functions, then
the pass-by-value semantics of R will push me beyond the limits at some
points. ?(This is an empirical statement, not a theoretical one. ?I was
bitten by it several times while trying to analyze a couple of these
datasets. And, yes, I know I can get around this by buying a bigger and
better machine; it's on order...) ?The real point is that using functions
can be detrimental to the efficiency of the program, in ways that have real
world consequences.

I haven't thought about doing the same thing with expressions. Expressions
don't have quite the same semantics as chunks, and you'd have to make sure
the evaluation was delayed so that you cold use the current values of things
that were computed in the meantime.... and I already know how to do this
with chunks without having to think so hard.

Using expressons would, however, help with the one difficulty that I have
with reusing <<chunks>> (independent of whether or not I use
'expand=FALSE'). ?I usually work inside emacs, using the
emacs-speaks-statistics (ESS) package. ESS doesn't know how to evaluate the
<<chunk>> call inside another chunk. so if I want to step through the code
during development, I have to jump around myself to locate the source
chunks. ?With expressions that wouldn't matter.

As I ramble on about this, it occurs to me that the underlying issue is that
<<chunks>> are not first class objects either in the LaTeX world or in the R
world part of Sweave. ?If there were a way to promote them to first class
objects somehow, then it might make my use of ESS easier while
simultaneously making it easier for Duncan to figure out how to report the
correct line numbers. ?But I only have an extremely vague idea of how one
might start to do that...