Tangling Gets Smarter in knitr

Note

This is one of a few posts on new features from a recent four-day knitr backlog sprint; see that post for the full details of the sprint.

Tangle is the old Literate Programming (e.g., WEB/Sweave) term for pulling the code out of a document and throwing away the prose. In knitr you do it with purl(): give it an .Rmd and you get back a .R script with just the code. It’s a small feature, but people lean on it more than I expected. In this development …