Added Rcpp compilation to vignette build.

[LTLA]

No description provided.

[eddelbuettel]

You could set eval=FALSE globally too.

Brooke Anderson and I used that super-cleverly in the R Journal paper on using drat for a data archive -- if the optional data is not there, the knitr chunks with not evaluate. After some pretest for a package we essentially do

# Code to add at the beginning of the vignette(s) of the code package to ensure vignette
# code is conditioned to only run if the data package is available
hasData <- requireNamespace("hurricaneexposuredata", quietly = TRUE)                #1
if (!hasData) {                                                                     #2
  knitr::opts_chunk$set(eval = FALSE)                                             #3
  msg <- paste("Note: Examples in this vignette require that the",
               "`hurricaneexposuredata` package be installed. The system",
               "currently running this vignette does not have that package",
               "installed, so code examples will not be evaluated.")
  msg <- paste(strwrap(msg), collapse="\n")
  message(msg)                                                                    #4
}

I think we discuss the trick in the paper too -- the hashmarks one to four here are references.

[LTLA]

Yeah, that's probably neater than having to set eval=FALSE manually.