[R-pkg-devel] failing S3 dispatch
Thanks Duncan, I finally found the reason for the mysterious dispatch-failure: I had an unwanted and unexported replicated definition of the 'clone' generic in ff's namespace (a left-over). I still don't understand how this prevented the proper dispatch since the duplicate in ff's namespace it was *not* called. I further experimented and *any* non-exported object matching the name of the generic caused the problem. Scary, maybe worth a check! Anyhow, removing the non-exported object solved the problem. Best regards Jens
On 20.10.21 13:43, Jens Oehlschl?gel wrote:
Thank you Duncan,
bit NAMESPACE has
S3method(clone,default)
export(clone)
ff NAMESPACE has
import(bit)
# wish of CRAN maintainers: export another time here (now maintained
and exported in bit)
# without this R CMD CHECK complained, but with it R CMD CHECK
complains also, how to export again and why?
# clone
#,clone.default
?clone.ff
,clone.ffdf
S3method("clone",ff)
S3method(clone, ffdf)
# wish of CRAN maintainers: export another time here (now maintained
and exported in bit)
#S3method(clone, default)
Best
Jens
On 20.10.21 11:02, Duncan Murdoch wrote:
On 19/10/2021 3:43 p.m., Jens Oehlschl?gel wrote:
I didn't find an answer elsewhere: My package 'bit' creates a S3 generic 'clone' and exports it. Furthermore it registers a S3 method 'clone.default' (not exported). My package 'ff' imports package 'bit' and exports and registers a new S3 method 'clone.ff'. However, calling 'clone(ffobj)' dispatches to clone.default instead of clone.ff !? Why?
You should show us the NAMESPACE entries involving clone and clone.ff from ff. Some comments that may or may not be relevant: ?- Normally you wouldn't export clone.ff, it's enough to register it using S3method(). ?- You may have created a new generic named clone, and that's what clone.ff would attach itself to.? You can have bit::clone and ff::clone as different generics and that would cause problems.
What is the recommended way to create new S3-methods that get dispatched? In earlier versions of the packages I simply exported everything - that worked.
I import the generic and use S3method(generic, method).? I don't export the methods, so I wouldn't be able to call z <- clone.ff(a). Duncan Murdoch
Best Jens ? > require(ff) ? > ? > a <- as.ff(0:9) ? > class(x) [1] "ff_vector" "ff" ? > ? > x <- clone(a) ? > y <- bit:::clone.default(a) ? > z <- clone.ff(a) ? > ? > # cloned ffobjects should have different filenames> ? > filename(a)? # original [1] "/tmp/Rtmpk17JRZ/ff/clone1ed54cbb5060.ff" ? > ? > filename(x)? # unexpected equal (dispatch to clone.default) [1] "/tmp/Rtmpk17JRZ/ff/clone1ed54cbb5060.ff" ? > ? > filename(y)? # expected equal [1] "/tmp/Rtmpk17JRZ/ff/clone1ed54cbb5060.ff" ? > ? > filename(z)? # OK [1] "/tmp/Rtmpk17JRZ/ff/clone1ed551d3ee66.ff" ? > version ? ?????????????? _ platform?????? x86_64-pc-linux-gnu arch?????????? x86_64 os???????????? linux-gnu system???????? x86_64, linux-gnu status major????????? 4 minor????????? 1.1 year?????????? 2021 month????????? 08 day??????????? 10 svn rev??????? 80725 language?????? R version.string R version 4.1.1 (2021-08-10) nickname?????? Kick Things
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