How to export S3method both as method and normal function using roxygen2

Question

There are similar, older questions out there, but since roxygen2 version 3.0.0 things have changed a bit (as I understand from other Q&A here on SO).

I have written an alternative function format.Date, which I want to export, both as method and as function.
Using the @export tag means roxygen2 recognises it as an S3-method for print, and registers it accordingly. And when I load my package, and print a date object, my method gets called. So far, so good.

But, when I then call format.Date, I still get the normal base-method. This also happens when I use debugonce(format.Date), the 'debug-mark' gets set on base::format.Date, so if my method gets called, nothing happens. Or if I want to inspect the source-code: very hard for a user to understand that what he sees with View(format.Date) is NOT what is executed.
And if a user looks into my package what functions I have provided, format.Date is not there.

So I want format.Date to be exported as both an S3-method, and as a normal function called format.Date. In order to do so, I expect my NAMESPACE file to contain both following lines:

S3method(format,Date)
export(format.Date)

Is this possible in roxygen2? I get the impression you could do this in earlier versions (as you could supply both @S3method/@method and @export), but I can't get it to work now.

Background-info: roxygen2 version 6.1.1 with R 3.5.1, run under Rstudio 1.1.453/MacOS 10.13.6

Answer 1

The ways I found are

1. @exportS3Method and an explicit @export line. Since roxygen2 changes often, this might change in the future:

   #' @exportS3Method fortify
   #' @export fortify.Date
   

2. Manually spelling out the NAMESPACE content (add no other @export or @method directives)

   #' @rawNamespace S3method(fortify,Date)
   #' export(fortify.Date)
   

Both will result in the NAMESPACE file containing the following lines, with the first one resulting in roxygen2 ordering things for you.

S3method(fortify,Date)
export(fortify.Date)