I wonder how to debug a web app in R. Rscript has the habit to tell you that there is an error, but not to tell you what file or line number. So debugging Rscript requires print statements to circle the problem. No something I enjoy to do, and certainly not something I want to for webdev.
It generally tells you the line number of the error, either in the web browser itself or in the R session that you're serving it from. I've never had a real problem with debugging the web app itself.
As for debugging the R code itself, options(error=traceback) is useful (though honestly usually unnecessary) as well.
