if (FALSE) # By defining .onAttach() as follows in zzz.R for a package, an
# instance of class Package with the same name as the package will
# be made available on the search path. More over, the code below
# will also inform the user that the package has been loaded:
#
# > library(R.oo)
# R.oo v0.52 (2003/04/13) was successfully loaded.
#
.onAttach <- function(libname, pkgname) {
pkg <- Package(pkgname)
assign(pkgname, pkg, pos=getPosition(pkg))
cat(getName(pkg), " v", getVersion(pkg), " (", getDate(pkg), ")",
" was successfully loaded.\n", sep="")
}
# The Package class works for any packages, loaded or not.
# Some information about the base package
pkg <- Package("base")
print(pkg)
# [1] "Package: base v3.6.2 is loaded (pos=14). Title: The R Base Package.
# The official webpage is NA and the maintainer is R Core Team . The package is installed in /usr/lib/R/library/base/.
# License: Part of R 3.6.2. Description: Base R functions. Type
# showNews(base) for package history, and ?base for help."
print(list.files(Package("base")$dataPath))
# Some information about the R.oo package
print(R.oo::R.oo)
# [1] "Package: R.oo v1.23.0-9000 . Title: R Object-Oriented Programming
# with or without References. The official webpage is https://github.com/
# HenrikBengtsson/R.oo and the maintainer is Henrik Bengtsson. The package
# is installed in /home/alice/R/x86_64-pc-linux-gnu-library/3.6/R.oo/.
# License: LGPL (>= 2.1). Description: Methods and classes for object-
# oriented programming in R with or without references. Large effort has
# been made on making definition of methods as simple as possible with a
# minimum of maintenance for package developers. The package has been
# developed since 2001 and is now considered very stable. This is a
# cross-platform package implemented in pure R that defines standard S3
# classes without any tricks. Type showNews(R.oo) for package history,
# and ?R.oo for help."
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