On Thu, 2010-08-19 at 17:07 -0400, Kevin Coombes wrote: > I use it, frequently. The idea for it goes back to some of Knuth's > original literate programming ideas for developing weave and tangle when > he was writing TeX (the program). I want to be able to document the > pieces of some complex algorithm without having to see all of the gory > details. For instance, I have code that looks like the following. > (Note that this is typed on the fly rather than copied from actual > source, so there may be typos.) > > <<mainloop,keep.source=TRUE,expand=FALSE>>= > for (i in 1:nSamples) { > <<getInfoAboutThisSample>> > for (j in 1:nChromosomes) { > <<getChromosomeDataForCurrentSample>> > <<normalizeChromosomeData>> > <<findSegments>> > <<computeSignificance>> > <<writeResults>> > } > } > @ > > Each of the <<chunks>> is itself a fairly long piece of code defined and > documented somewhere else. (Some of them may themselves be written in > the same form to reduce the final size of a chunk to something a human > has a chance of understanding. That's the difference between weave and > tangle in the original implementation.) By blocking expansion, I can > focus on the main steps without having them lost in pages and pages of code. >
Couldn't you achieve the same amount of abstraction using function calls, rather than embedded code chunks? The reader can then see real code, rather than non-code, or meta-code, or whatever. Alternatively, represent the code chunks as R expressions, then evaluate the expressions at the appropriate points. -Matt > So I vote strongly for retaining "expand=FALSE". > > Best, > Kevin > > Duncan Murdoch wrote: > > On 19/08/2010 4:29 PM, Claudia Beleites wrote: > >> I never used it. > >> > >> I got curious, though. What would be a situation that benefits of > >> this option? > >> > > > > When I put it in, I thought it would be for people who were writing > > about Sweave. > > > > Duncan Murdoch > > > >> Maybe a use case could be found by "brute force" (grep all .Rnw files > >> on CRAN for the option? > >> > >> Claudia > >> > >> > > > > ______________________________________________ > > R-devel@r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-devel > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel -- Matthew S. Shotwell Graduate Student Division of Biostatistics and Epidemiology Medical University of South Carolina ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel