A vignette is a long-form guide to your package. Function documentation is great if you know the name of the function you need, but it’s useless otherwise. A vignette is like a book chapter or an academic paper: it can describe the problem that your package is designed to solve, and then show the reader how to solve it. A vignette should divide functions into useful categories, and demonstrate how to coordinate multiple functions to solve problems. Vignettes are also useful if you want to explain the details of your package. For example, if you have implemented a complex statistical algorithm, you might want to describe all the details in a vignette so that users of your package can understand what’s going on under the hood, and be confident that you’ve implemented the algorithm correctly.
Many existing packages have vignettes. You can see all the installed vignettes with
browseVignettes(). To see the vignette for a specific package, use the argument
browseVignettes("packagename"). Each vignette provides three things: the original source file, a readable HTML page or PDF, and a file of R code. You can read a specific vignette with
vignette(x), and see its code with
edit(vignette(x)). To see vignettes for a package you haven’t installed, look at its CRAN page (e.g., http://cran.r-project.org/web/packages/dplyr).
Before R 3.0.0, the only way to create a vignette was with Sweave. This was challenging because Sweave only worked with LaTeX, ...