Hi Martin,
Thanks. I figured that out after trying it myself, so I didn't do that.
OTOH, a whole new package just so I can extend a method... I feel that life
is too short. So, I cut the Gordian knot and just wrote as_FlexTable
instead of as.FlexTable, and skipped the whole inheritance issue.
Cheers,
David
On 14 March 2017 at 16:35, Martin Maechler <maech...@stat.math.ethz.ch>
wrote:
> >>>>> David Hugh-Jones <davidhughjo...@gmail.com>
> >>>>> on Tue, 14 Mar 2017 09:26:49 +0000 writes:
>
> > Just out of interest, what would happen if I used the hacky solution
> of
> > simply exporting my own method like:
>
> > as.FlexTable <- function(x, ...) UseMethod("as.FlexTable")
>
> > I am fairly sure you will tell me that fire and brimstone will rain
> down…
> > But it sure seems simple compared to writing another package and
> getting
> > it on CRAN...
>
> no fire etc, but pretty close ;-)
>
> You will have two (internal) methods tables for as.FlexTable,
> one in ReporteRs, one in your package, and from a user point of
> view there's a deep abyss in functionality between working with
>
> require(ReporteRs); require(huxtable)
>
> and working with
>
> require(huxtable); require(ReporteRs)
>
> This is undesirable and error prone and can be resolved by
> correct imports as those mentioned.
>
> Martin
>
> > David
>
> > On Tue, 14 Mar 2017 at 09:06, Martin Maechler <
> maech...@stat.math.ethz.ch>
> > wrote:
>
> >> >>>>> David Hugh-Jones <davidhughjo...@gmail.com>
> >> >>>>> on Tue, 14 Mar 2017 02:46:35 +0000 writes:
> >> >>>>> David Hugh-Jones <davidhughjo...@gmail.com>
> >> >>>>> on Tue, 14 Mar 2017 02:46:35 +0000 writes:
> >>
> >> > Hi,
> >> > Cross-posted from SO:
> >> >
> >> http://stackoverflow.com/questions/42776058/extending-
> an-s3-generic-from-an-optional-package
> >>
> >> ((sent my answer there as well))
> >>
> >> > I have a package which provides an as.FlexTable method for its
> >> objects,
> >> > extending the S3 generic from the ReporteRs package. So, my
> >> NAMESPACE file,
> >> > generated by roxygen, has lines:
> >>
> >> > importFrom(ReporteRs,as.FlexTable)
> >> > ...
> >> > S3method(as.FlexTable,huxtable)
> >> > ...
> >> > export(as.FlexTable)
> >>
> >> > I don't much want to put ReporteRs in Imports: in the DESCRIPTION
> >> file,
> >> > because it involves a big external dependency on Java. But, when I
> >> put it
> >> > into Suggests:, R CMD check gives me errors like "Namespace
> >> dependency not
> >> > required".
> >>
> >> > Is there anyway I can extend the generic without making a hard
> >> dependency?
> >>
> >> No. Importing is a hard dependency..
> >> Some people do not import formally but use '<pkgNamespace>::<obj>'
> >> instead, *and* conditionalize their code on the availability of
> >> that namespace.
> >> I don't recommend that at all, and particularly not for
> >> extending a generic.
> >>
> >> I recommend you talk with the maintainer of 'ReporteRs':
> >> 1) You could use a common (yet-to-create) very small package say
> >> 'flexS3generics'
> >> which provides S3 generics (and S4 if ..) you want to use
> >> both, and then both you and her/him import from that mini package.
> >> You'd be both authors of that package.
> >>
> >> 2) If your package is much smaller (in its footprint, incl
> >> dependencies) than 'ReporteRs' she/he may agree to import the
> >> S3 generic from your package instead of the other way around.
> >>
> >> Both are clean solutions,
> >> and both need some time-coordination when releasing to CRAN,
> >> '1)' being easier: Once the 'flexS3generics' is released to
> >> CRAN, change (both) your package(s) to
> >> importFrom(flexS3generics,*) but these changes and CRAN
> >> submissions are then independent of each other.
> >>
> >>
> >> > Cheers,
> >> > David
> >>
> >> --
> > Sent from Gmail Mobile
>
> > [[alternative HTML version deleted]]
>
>
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