从R包导出环境

Question

I am developing an R package that wraps the rmongodb package and creates a developer-friendly interface for working with MongoDB. The package uses proto internally.

I'd like to export a single factory method via a proto object (an environment) called MongoDB , whose definition is:

MongoDB <- proto(
  new = function(., ...) {
    # Good stuff in here...
  }
)

During development with RStudio & devtools and during local testing this does not seem to be a problem. However, I am experiencing several problems:

• devtools::check() insists on putting an import(MongoDB) in my NAMESPACE file which makes R CMD check fail with "Namespace dependency not required: 'MongoDB'".

• When I remove this import directive, R CMD check fails with "object 'MongoDB' not found" while running my testthat tests, even if I manually add export(MongoDB) . However, devtools::test() works fine in RStudio.

What is the recommended way of exporting proto objects, which are environments, from R packages?

Update:

Per Gabor's suggestion below, I've made sure that MongoDB.Rd declares MongoDB as data (the link has the source). I still get a failure in MongoDB not being visible in the tests (which use testthat ). My DESCRIPTION file is here and NAMESPACE is here .

Answer 1

Try this:

1. Specify export("MongoDB") in your NAMESPACE file to make the MongoDB proto object publicly available.
2. Specify LazyData: yes in your DESCRIPTION file so that it automatically loads when accessed.
3. Add an .Rd file documenting it as a dataset.

It should then pass R CMD check .

Answer 2

This directive :

import(MongoDB)

means that you import the MongoDB namespace into your package. Probably not what you want if i understand correctly.

I think you want to export the MongoDB object, then

export(MongoDB) 

should work fine.