Rcmdr package dependencies
Dear Uwe,
-----Original Message----- From: Uwe Ligges [mailto:ligges at statistik.tu-dortmund.de] Sent: September-22-09 2:17 PM To: John Fox Cc: r-devel at r-project.org Subject: Re: [Rd] Rcmdr package dependencies John Fox wrote:
Dear r-devel members, My Rcmdr package "depends" on several other packages (tcltk, grDevices, utils, and car) and "suggests" a number of others (abind, aplpack, colorspace, effects, foreign, grid, Hmisc, lattice, leaps, lmtest, MASS, mgcv, multcomp, nlme, nnet, relimp, rgl, and RODBC). The reason for the distinction is that I don't want all of these packages to load when the Rcmdr loads; rather, the "suggested" packages are loaded as they're
needed.
But all of the packages -- both those under "depends" and those under "suggests" -- really are necessary for all of the features of the Rcmdr
to
work. For example, if the "leaps" package is absent, then the "Subset
model
selection" item in the "Models" menu is suppressed. This arrangement works reasonably well, but it makes it awkward to
install
the Rcmdr. If the user issues the command install.packages("Rcmdr"),
then
the "suggested" packages aren't installed. On the other hand, if the
user
issues the command install.packages("Rcmdr", dependencies=TRUE), which
is
what I currently recommend, then "suggested" packages are installed recursively, causing dozens of packages, most of them actually
unnecessary,
to be installed. This issue has been growing more acute, and at this
point
even with a fast Internet connection it takes quite a while for all of
the
dependencies to download and install. I wonder whether I've missed something. Is there a way for me to arrange
the
Rcmdr package dependencies so that only the necessary packages (those currently listed under both "depends" and "suggests" and the packages on which they "depend") are installed along with the Rcmdr, but the
currently
"suggested" packages aren't loaded when the Rcmdr loads?
Dear John, no, this is not possible. Consider your package A (or Rcmdr) suggests B that suggests C. Then A::foo uses the function B::bar which only works if C::dep is present. B works essentially without C but it requires C just to make bar work. Then this means your A::foo won't work if C is not installed and you won't get it with the setup mentioned above. In summary, I fear what you want might work well *now* (by chance), but it does not work in general.
I agree that what I want to do isn't bullet-proof. I think, however, that in most, if not all, cases, the Rcmdr dialogs will work even if packages suggested by currently directly suggested packages were not installed. In fact, this is what happens when a package is installed with the default dependencies=FALSE. If it turns out that some such indirect dependency is actually necessary, I could add that package to those directly suggested (were such a mechanism possible). I'd save users a lot of downloads at the price of occasionally having to specify a dependency explicitly. Thanks, John
Best wishes, Uwe
Any help would be appreciated. John ------------------------------ John Fox, Professor Department of Sociology McMaster University Hamilton, Ontario, Canada web: socserv.mcmaster.ca/jfox
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