[Rd] Recommended way to call/import functions from a Suggested package

[Davor Cubranic]

I don't see any warnings if MASS is listed in Suggests in the DESCRIPTION.

Davor

On 2013-02-25, at 1:28 PM, Hadley Wickham wrote:

>> To summarize, it appears that the only way to call functions from a
>> suggested package is by using either 'require' (which will dynamically
>> attach it) or the double colon method. Is this something that should be
>> mentioned in R-exts?
> 
> Except the double colon method doesn't work (i.e. does not pass R CMD
> check) unless you also import the package, which means it's no longer
> just a suggestion - it must always be installed.
> 
> A simple test case (attached DESCRIPTION and R/test.r) yields this
> warning on R CMD check:
> 
> * checking for unstated dependencies in R code ... WARNING
> '::' or ':::' import not declared from: 'MASS'
> See the information on DESCRIPTION files in the chapter 'Creating R
> packages' of the 'Writing R Extensions' manual.
> 
> Hadley
> 
> -- 
> Chief Scientist, RStudio
> http://had.co.nz/
> <test.r><DESCRIPTION>