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
>
>
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