On 9/12/2013 1:37 PM, Duncan Murdoch wrote:
I think this one would be fine if you had library(MASS) or
require(MASS) or (probably best) used MASS::loglm explicitly. It may
be that in the past some other package put MASS on the search list,
and that's why it worked before.
The distinction is between "loading" and "attaching" a package.
Loading it (which would be done if you had MASS::loglm, or imported
it) guarantees that the package is initialized and in memory, but
doesn't make it visible to the user without the explicit MASS::
prefix. Attaching it first loads it, then modifies the user's search
list so the user can see it.
Loading is less intrusive, so it's preferred over attaching. Both
library() and require() would attach it.
Thanks for this explanation, but I'm still confused about how to avoid
the wrath of the CRAN-devel
daemon, whose appetite for new morsels of developer flesh seems ever
increasing and makes
keeping even a stable package up-to-date a moving target. Perhaps such
changes in R devel
should be announced on this list for public comment before they are
enforced in R CMD check.
In vcdExtra, I use MASS::loglm in ~ 6 .Rd examples, a vignette, and also
provide R code that
extends *.loglm methods. All of this previously worked by including
Suggests: MASS, ...
Changing this to Imports: MASS seems rather heavy-handed; I don't really
want/need all of MASS
in my namespace, and using MASS::loglm in examples seems ugly. For now,
I'll use
require(MASS) in each example.
Attaching it first loads it, then modifies the user's search list so
the user can see it.
Which directive does this?
--
Michael Friendly Email: friendly AT yorku DOT ca
Professor, Psychology Dept. & Chair, Quantitative Methods
York University Voice: 416 736-2100 x66249 Fax: 416 736-5814
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