On 02/26/2013 03:12 PM, Simon Urbanek wrote:
On Feb 26, 2013, at 5:47 PM, Hervé Pagès wrote:Hi, So MASS::huber(1:10) seems to do the job i.e. (1) loads the MASS package (if it's installed), (2) does not pollute the search path, (3) no 'R CMD check' warning if MASS is listed in Suggests, and (4) descent error message if MASS is not installed: > MASS::huber(1:10) Error in loadNamespace(name) : there is no package called ‘MASS’But (4) is a problem - it may not fail without MASS since it is only suggested, that's why you need the try() ...
Not everybody needs the try(). Some functions in my package won't beable to return anything if the suggested package is not installed, so they will have to fail, preferably loudly rather than silently. A pretty common situation.
Believe it or not, the discussion was not just about the recommended way to call functions from the multicore package or another package providing some kind of support for parallelization, where not having it installed doesn't diminish the set of functionalities provided by my package, only makes it slower.
The whole thread (which you omitted) was started because the usual
if(require(...)) { .. } has an unwanted side-effect which the requestor did not
want so the question was what does the job and that got settled before you
joined in ...
I didn't omit the thread: I actually read every answer including yours. Are you claiming your solution is the recommended one? Thanks for clarifying. Also as suggested by some posts in this thread, a clarification in the official documentation would be nice. Thanks, H.
Cheers, SSo is this recommendable or are there good reasons for stating in the manual that "this approach is usually not recommended"? (In which case it would be good to know what the recommended way is.) Thanks, H. On 02/25/2013 02:56 PM, Hadley Wickham wrote:loadNamespaces loads but does not attach the package. Suggests: is enough to quieten the warning with ~/tmp$ R --version R Under development (unstable) (2013-02-21 r62017) -- "Unsuffered Consequences" This is consistent with RShowDoc("R-exts") section 1.1.1 Namespaces accessed by the ‘::’ and ‘:::’ operators must be listed here, or in ‘Suggests’ or ‘Enhances’ (see below).I guess that's changed since I last tried it. (My reproducible example forgot to include MASS in the Suggests :/ ) Thanks! Hadley-- Hervé Pagès Program in Computational Biology Division of Public Health Sciences Fred Hutchinson Cancer Research Center 1100 Fairview Ave. N, M1-B514 P.O. Box 19024 Seattle, WA 98109-1024 E-mail: hpa...@fhcrc.org Phone: (206) 667-5791 Fax: (206) 667-1319
-- Hervé Pagès Program in Computational Biology Division of Public Health Sciences Fred Hutchinson Cancer Research Center 1100 Fairview Ave. N, M1-B514 P.O. Box 19024 Seattle, WA 98109-1024 E-mail: hpa...@fhcrc.org Phone: (206) 667-5791 Fax: (206) 667-1319 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
