R/utils_packages.R

In wlandau/crew: A Distributed Worker Launcher Framework

load_packages <- function(packages, library) {
  out <- suppressPackageStartupMessages(
    lapply(
      packages,
      require,
      lib.loc = library,
      quietly = TRUE,
      character.only = TRUE
    )
  )
  out <- as.logical(unlist(out))
  msg <- paste(
    "could not find packages",
    paste(packages[!out], collapse = ", "),
    "in library paths",
    paste(library, collapse = ", ")
  )
  crew_assert(all(out), message = msg)
}

package_installed <- function(package) {
  result <- .subset2(packages_installed, package)
  if (is.null(result)) {
    result <- rlang::is_installed(pkg = package)
    packages_installed[[package]] <- result
  }
  result
}

packages_installed <- new.env(parent = emptyenv(), hash = TRUE)