On 19 October 2016 at 19:29, Berry Boessenkool wrote:
| A package I am developing will have one additional (not core) function
depending on RCurl.
| To keep dependencies low, I am considering to put RCurl in 'Suggests' instead
of 'Imports'.
| Also, I guess some users / systems may not have libcurl installed.
|
| Then I would write something like
| indexDWD <- function(...)
| {
| if(!requireNamespace("RCurl", quietly=TRUE))
| stop("The R package 'RCurl' is not available. indexDWD can not obtain file
list.\n",
| "install.packages('RCurl') to enable this.")
| ... # otherwise do some nice stuff with RCurl::getURL
| }
|
| Can /should I still have an example tested by CRAN? (I've seen \dontrun used
in similar situations)
| Or should CRAN check never depend on an ftp-server being accessible?
What you have is the correct approach: test _if the package can be loaded_
and if so, proceed. Else skip the test.
Some just put packages in Suggests: and then still assume them be installed.
That's just wrong in my book, though not enforced as a fail by CRAN.
Dirk
--
http://dirk.eddelbuettel.com | @eddelbuettel | e...@debian.org
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