>>>>> Michael Chirico via R-devel
>>>>> on Mon, 9 Jan 2023 12:25:46 -0800 writes:
> require() and library() both emit this message immediately before
> running library():
> "Loading required package: %s"
>
https://github.com/r-devel/r-svn/blob/4198a2941b702d965bb2374c2b908f48c369f40a/src/library/base/R/library.R#L967-L968
>
https://github.com/r-devel/r-svn/blob/4198a2941b702d965bb2374c2b908f48c369f40a/src/library/base/R/library.R#L684-L685
> Shouldn't "Loading" be "Attaching" instead?
Good question... I had asked myself as well a couple of times.
The vagueness is mostly "historical" in the sense that
originally R (nor S) had namespaces.
OTOH, attach(.) has always worked for data frames (already in pre-R S).
Still, I agree (when teaching and otherwise), we should
clearly distinguish the two notably in the context of packages
and their namespaces.
> My understanding is "a package is loaded" is equivalent to
> "isNamespaceLoaded()", i.e., loadNamespace() was run. And that "a
> package is attached" is equivalent to "pkg %in% .packages()", i.e.,
> library(pkg) was run.
or (easier for teaching) that "package:<pkg>" %in% search()
-- which is what .packages() does {by default}.
I agree with the above.
> Is the terminology not so precise?
> There's certainly ambiguity in the internal variable names referenced
> above -- in require, we see
> loaded <- paste0("package:", package) %in% search()
>
https://github.com/r-devel/r-svn/blob/4198a2941b702d965bb2374c2b908f48c369f40a/src/library/base/R/library.R#L680
again, historical: require() exists for considerably longer
than namespaces.
I think we should at least change the message printed by
require() and library() you mentioned above.
Martin
> Whereas in library() [via .getRequiredPackages2()] we see
> attached <- paste0("package:", pkg) %in% search()
>
https://github.com/r-devel/r-svn/blob/4198a2941b702d965bb2374c2b908f48c369f40a/src/library/base/R/library.R#L931
> Mike C
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