Guidelines on how to use custom extract() in distinct package?

[MatthieuStigler]

Hi

I would like to write a custom extract() function for a custom class and keep that extract.custom in an other package. Do you have guidelines on how to do this (instead of sending PR to texreg), similar to how one would do with a custom tidy function (Create your own broom tidier methods)?

I see for example that package panelvar uses:

extract <- function(model, ...) UseMethod("extract")
extract.pvargmm

and then in NAMESPACE:

export(extract)
S3method(extract,pvarfeols)

It seems this could create some issues, as discussed for tidy?

Please do not define tidy(), glance(), or augment() generics in your package. This will result in namespace conflicts whenever your package is used along other packages that also export tidying methods

Hence the question: do you have advice (or examples) on recommended way to add a custom extract, without sending it to texreg?

Thanks!

[leifeld]

I'm not sure what the official guidance on this is. I've actually been wondering, too. If you (or anyone else) has ideas or comes across any guidance, please post here. My best guess would be something like this:

1. Import the generic function in your other package:
   importFrom("texreg", "extract")
2. Implement your method:
   setMethod("extract", "your_class_name", function(model) { ... })
3. Either put texreg under Imports: in the DESCRIPTION file, or put it under Suggests: and add conditional checks in the code to ensure an error message is printed if texreg is not installed or some other fallback exists. I have some of those in the texreg code as well.
4. Ideally, add useful documentation and testthat unit tests, but up to you.

[MatthieuStigler]

excellent, thanks a lot @leifeld !!