R/on_path.r

In baslat/sak: The Swiss Army Knife of R

#' Check if something is on the system path (Windows only)
#'
#' Check if something is on the system path. It does this by using the
#' `where.exe` utility.
#'
#' @param what (character) a string, typically to file
#' @param verbose (logical; default = `TRUE`) message the path location?
#'
#' @return logical, \code{TRUE} if a match is found
#' @export
#'
#' @examples
#' \dontrun{
#' # Is Rscript on path?
#' on_path(what = "Rscript")
#' }
on_path <- function(what, verbose = TRUE) {
  # only runs on windows
  if (.Platform[["OS.type"]] != "windows") {
    message("This only runs on Windows")
    invisible(FALSE)
  }

  # where.exe is in C:\Windows\System32\where.exe, so should be usable
  res <- run_well("where.exe",
    args = what,
    capture_error = TRUE
  )

  if (verbose) {
    res %>%
      paste(collapse = "\n") %>%
      message()
  }

  any(fs::is_file(res))
}