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() ... 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 ... Cheers, S > So 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 > > ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel