I think we should try to advance and hopefully finalize this
thread before we forget about it ..
>>>>> Michael Chirico n Thu, 11 Apr 2024 09:10:11 -0700 writes:
>> I would assume that
>> library(Matrix, include.only="isDiagonal")
>> implies that only `isDiagonal` ends up on the search path
> This could also be a reasonable behavior, but neither does that happen
> today.
Indeed; I think we should signal a warning at least in the case
it does not happen --- namely when "parts of Matrix" are already
in the search path.
>> I think a far better approach to solve Michael's problem is simply to use
>> fac2sparse <- Matrix::fac2sparse
> This does not fully simulate attachment, e.g. running package hooks &
> resolving Depends.
(indeed; as library() is really about search() patch attchment)
>> ?library could also mention using detach() followed by library() or
>> attachNamespace() with a new include.only specification.
> This is the "quite hard to accomplish" I alluded to, admittedly I hadn't
> forced myself to write it all out -- maybe it's not as bad as all that.
> After some iterations, today I think we'd want to do...
> modify_attach <- function(pkg, new_names) {
> if (!startsWith(pkg, "package:")) pkg <- paste0("package:", pkg)
> old <- tryCatch(ls(pkg, all.names=TRUE), error=\(c) character())
> if (length(old)) detach(pkg)
> attachNamespace(.rmpkg(pkg), include.only=c(new_names, old))
> }
> Perhaps detach() could invisibly return the exported names to make this a
> tiny bit easier (today it returns NULL):
I agree that such changed detach() behavior would be "nice" here;
but I wouldn't like to change its default behavior, notably as
in 99.5% of its use, the names would not be used.
I'd agree to add a new option for detach() to return the names
(visibly in that case).
> modify_attach <- function(pkg, new_names) {
> if (!startsWith(pkg, "package:")) pkg <- paste0("package:", pkg)
> old <- tryCatch(detach(pkg), error=\(c) character())
> attachNamespace(.rmpkg(pkg), include.only=c(new_names, old))
> }
> Regardless, I think your suggestion to just point to
> detach()+attachNamespace() is reasonable enough, the rare users that care
> about this are likely to be able to figure out the rest from there.
So I think we agree here; mentioning such a modify_attach()
... I'd use an example *without* tryCatch() as I think the user
should choose their own line of action in such cases
...
on the help page would then be appropriate.
Martin
> On Thu, Apr 11, 2024 at 7:37 AM <luke-tier...@uiowa.edu> wrote:
>> On Thu, 11 Apr 2024, Duncan Murdoch wrote:
>>
>> > On 11/04/2024 7:04 a.m., Martin Maechler wrote:
>> >>>>>>> Michael Chirico
>> >>>>>>> on Mon, 8 Apr 2024 10:19:29 -0700 writes:
>> >>
>> >> > Right now, attaching the same package with different
>> include.only= has no effect:
>> >>
>> >> > library(Matrix, include.only="fac2sparse")
>> >> > library(Matrix)
>> >> > ls("package:Matrix")
>> >> > # [1] "fac2sparse"
>> >>
>> >> > ?library does not cover this case -- what is covered is the
_loading_
>> >> > behavior of repeated calls:
>> >>
>> >> >> [library and require] check and update the list of currently
attached
>> >> > packages and do not reload a namespace which is already loaded
>> >>
>> >> > But here we're looking at the _attach_ behavior of repeated
calls.
>> >>
>> >> > I am particularly interested in allowing the exports of a
>> package to be
>> >> > built up gradually:
>> >>
>> >> > library(Matrix, include.only="fac2sparse")
>> >> > library(Matrix, include.only="isDiagonal") #
want:ls("package:Matrix") -->
>> >> > c("fac2sparse", "isDiagonal")
>> >> > ...
>> >>
>> >> > It seems quite hard to accomplish this at the moment. Is the
behavior to
>> >> > ignore new inclusions intentional? Could there be an argument
to get
>> >> > different behavior?
>> >>
>> >> As you did not get an answer yet, ..., some remarks by an
>> >> R-corer who has tweaked library() behavior in the past :
>> >>
>> >> - The `include.only = *` argument to library() has been a
>> >> *relatively* recent addition {given the 25+ years of R history}:
>> >>
>> >> It was part of the extensive new features by Luke Tierney for
>> >> R 3.6.0 [r76248 | luke | 2019-03-18 17:29:35 +0100], with NEWS
entry
>> >>
>> >> • library() and require() now allow more control over handling
>> >> search path conflicts when packages are attached. The policy is
>> >> controlled by the new conflicts.policy option.
>> >>
>> >> - I haven't seen these (then) new features been used much,
unfortunately,
>> >> also not from R-core members, but I'd be happy to
>> >> be told a different story.
>> >>
>> >> For the above reasons, it could well be that the current
>> >> implementation {of these features} has not been exercised a lot
>> >> yet, and limitations as you found them haven't been noticed yet,
>> >> or at least not noticed on the public R mailing lists, nor
>> >> otherwise by R-core (?).
>> >>
>> >> Your implicitly proposed new feature (or even *changed*
>> >> default behavior) seems to make sense to me -- but as alluded
>> >> to, above, I haven't been a conscious user of any
>> >> 'library(.., include.only = *)' till now.
>> >
>> > I don't think it makes sense. I would assume that
>> >
>> > library(Matrix, include.only="isDiagonal")
>> >
>> > implies that only `isDiagonal` ends up on the search path, i.e.
>> > "include.only" means "include only", not "include in addition to
whatever
>> > else has already been attached".
>> >
>> > I think a far better approach to solve Michael's problem is simply to
use
>> >
>> > fac2sparse <- Matrix::fac2sparse
>> > isDiagonal <- Matrix::isDiagonal
>> >
>> > instead of messing around with the user's search list, which may have
been
>> > intentionally set to include only one of those.
>> >
>> > So I'd suggest changing the docs to say
>> >
>> > "[library and require] check and update the list of currently attached
>> > packages and do not reload a namespace which is already loaded.
>> > If a package is already attached, no change will be made."
>>
>> ?library could also mention using detach() followed by library() or
>> attachNamespace() with a new include.only specification.
>>
>> Best,
>>
>> luke
>>
>> >
>> > Duncan Murdoch
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