[Rd] S3 weirdness

[Gabriel Becker]

On Thu, Jun 24, 2021 at 4:48 PM Gabor Grothendieck <ggrothendieck using gmail.com>
wrote:

> The fact that zoo:: in one part of the code has a side effect in
> another seems not to be in the spirit of functional programming or
> modularity.
>

While this is true, there is no way I know of for a package function
to...well, function in the general case without its namespace loaded, and
as has been brought up many times on this list, unloading namespaces fully
also doesn't work in the fully general case. Given those facts, it seems
the current behavior is essentially all that is possible to be done, right?

Also even if a namespace could be unloaded, can you imagine the penalty if
the namespace was loaded and then unloaded after every :: call? Some
scripts would just never complete at all. I kid, of course, but not by that
much I think...

~G


>
> On Thu, Jun 24, 2021 at 6:51 PM Simon Urbanek
> <simon.urbanek using r-project.org> wrote:
> >
> > Gabor,
> >
> > just by using zoo::read.zoo() you *do* load the namespace:
> >
> > > args(zoo::read.zoo)
> > function (file, format = "", tz = "", FUN = NULL, regular = FALSE,
> >     index.column = 1, drop = TRUE, FUN2 = NULL, split = NULL,
> >     aggregate = FALSE, ..., text, read = read.table)
> > NULL
> > > sessionInfo()
> > R Under development (unstable) (2021-06-23 r80548)
> > Platform: x86_64-apple-darwin19.6.0 (64-bit)
> > Running under: macOS Catalina 10.15.7
> >
> > Matrix products: default
> > BLAS:   /Volumes/Builds/R/build/lib/libRblas.dylib
> > LAPACK: /Volumes/Builds/R/build/lib/libRlapack.dylib
> >
> > locale:
> > [1] en_NZ.UTF-8/en_NZ.UTF-8/en_NZ.UTF-8/C/en_NZ.UTF-8/en_NZ.UTF-8
> >
> > attached base packages:
> > [1] stats     graphics  grDevices utils     datasets  methods   base
> >
> > loaded via a namespace (and not attached):
> > [1] zoo_1.8-9       compiler_4.2.0  grid_4.2.0      lattice_0.20-44
> >
> > which includes S3 method dispatch tables:
> >
> > > methods(as.ts)
> > [1] as.ts.default* as.ts.zoo*     as.ts.zooreg*
> > see '?methods' for accessing help and source code
> >
> > so the behavior is as expected.
> >
> > Cheers,
> > Simon
> >
> >
> > > On 25/06/2021, at 9:56 AM, Gabor Grothendieck <ggrothendieck using gmail.com>
> wrote:
> > >
> > > If we start up a vanilla session of R with no packages loaded and
> > > type the single line of code below as the first line entered then
> > > we get the output shown below.  The NA in the output and the length
> > > of 7 indicate that as.ts dispatched as.ts.zoo since as.ts.default
> > > would have resulted in a length of 6 with no NA's. It should not have
> > > known about as.ts.zoo since we never  explicitly loaded the zoo
> > > package using library or require.
> > > zoo:: was only used to refer to read.zoo.  This seems to be a bug in
> > > the way R is currently working.
> > >
> > >  as.ts(zoo::read.zoo(BOD))
> > >  ## Time Series:
> > >  ## Start = 1
> > >  ## End = 7
> > >  ## Frequency = 1
> > >  ## [1]  8.3 10.3 19.0 16.0 15.6   NA 19.8
> > >
> > >  R.version.string
> > >  ## [1] "R version 4.1.0 RC (2021-05-16 r80303)"
> > >
> > > --
> > > Statistics & Software Consulting
> > > GKX Group, GKX Associates Inc.
> > > tel: 1-877-GKX-GROUP
> > > email: ggrothendieck at gmail.com
> > >
> > > ______________________________________________
> > > R-devel using r-project.org mailing list
> > > https://stat.ethz.ch/mailman/listinfo/r-devel
> > >
> >
>
>
> --
> Statistics & Software Consulting
> GKX Group, GKX Associates Inc.
> tel: 1-877-GKX-GROUP
> email: ggrothendieck at gmail.com
>
> ______________________________________________
> R-devel using r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>

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