[R] Include pre-existing PDF files as vignettes in an R package?

[Michael Hannon]

Greetings.  The group that I work with has just started using the approach
outlined in Karl Broman's handy primer:

    http://kbroman.org/pkg_primer/pages/vignettes.html

to create vignettes for a couple of R packages.

This works fine as long as we have a current Rmd version of the vignette.  But
we have some old PDF documents that we'd like to include as vignettes as well.
I'd like to know if there's a way to include such PDF files as vignettes.

We *do* have the source files for the PDF files in question, but it would be
tedious to convert those source files to Rmd format.

My first thought was simply to add the PDF files to the .../vignettes
subdirectory and run the devtools::build_vignettes() function (mentioned in
the Broman tutorial), but that doesn't work.  I.e., the PDF files don't appear
in the list of vignettes for the package.

And after running devtools::build_vignettes I see that there's a lot of
additional stuff in:

    ...lib/R/site-library/<package_name>/...

so I don't see any obvious way to "fool" R into using the PDF files that
haven't gone through the whole knitr/rmarkdown process.  (Not to mention that
such an approach would be fragile at best.)

Suggestions welcome.  Thanks.

-- Mike