On-demand importing of a package
On Fri, Nov 25, 2011 at 2:47 PM, Jakson Alves de Aquino
<jalvesaq at gmail.com> wrote:
On Fri, Nov 25, 2011 at 2:40 PM, Gabor Grothendieck <ggrothendieck at gmail.com> wrote:
I think that the following procedure has the result that you want: Put in the DESCRIPTION file: Imports: RSQLite And in the R code write something like: RSQLite::AnRSQLiteFunction()
I had been thinking of using Imports in DESCRIPTION but was concerned that that would put RSQLite objects ahead of everything else on sqldf's search path even when not wanted but I gather you are intending that Imports be used in DESCRIPTION: but _not_ in the NAMESPACE file. ?I think that that would likely work. I will test it out to be sure. What I would probably want to do is to require() RSQLite in case the user wants to mix sqldf and RSQLite calls and I will check whether the check procedure allows that if the package is only named in Imports but, if not, it might be sufficient to put RSQLite in both Imports and Suggests. ?Thanks.
I have done this with the 'descr' package. It wasn't necessary to put the imported packages in two places, only in the "Imports" field. This was enough to make R install all dependencies but not load then along with 'descr'.
I just tried it but I wanted to require() RSQLite so that the user can access its facilities as well and although putting it just in Imports does work the check complains about requiring a package that has not been declared unless I put it in Suggests as well. If I don't do a require() then it would not be necessary to put it in Suggests so there seems to be a slight difference between descr and sqldf.
Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com