[Rd] Deprecated to Defunct

[Martin Maechler]

>>>>> Therneau, Terry M , Ph D via R-devel 
>>>>>     on Wed, 30 Jul 2025 09:04:39 -0500 writes:

    > In the survival package the survConcordance function was replaced by concordance a while 
    > ago, the latter works for any ordered response (continuous, binary, survival, ...).

    > I deprecated the old one a couple of years ago.

    > How long should I have this persist before converting it to Defunct and removing the old 
    > function?

    > Terry

    > -- 
    > Terry M Therneau, PhD
    > Department of Quantitative Health Sciences
    > Mayo Clinic
    > therneau using mayo.edu

    > "TERR-ree THUR-noh"


Making it defunct is different than removing it.
You'd replace the old function by a much shorter version

survConcordance <- function(formula, data, weights, subset, na.action) 
    .Defunct("concordance")

and also update help files, and possibly examples / demos /
tests.

For such an important and long-history package as `survival`
I'd then keep this little bit of code and docs  "forever".

If in 20 years, somebody tries to run R code from a script or a
book that is 30 years old,  they would still be happy to be
shown why their code calling  survConcordance()  does not run,
and how they can amend it ..

Martin