Exporting Non-S3-Methods with Dots in the Name Using Roxygen2 V4

Exporting non-S3-methods with dots in the name using roxygen2 v4

As Mr Flick commented, appending the full function name to the roxygen line works correctly. If I change the line to:

#' @export check.arg

then the NAMESPACE file contains:

export(check.arg)

roxygen2: Issue with exporting print method

I have found a solution for my problem (In comments above) and it may work for yours. In The NEWS.md file for v3.0.0, it is mentioned that @method tag is not needed as roxygen2 will figure it out, but it's sill available in the rare case that roxygen2 cannot do so. My solution:

#' @method print myClass    
#' @export    
print.myClass <- function(x) print("myClass")

This gives me back the S3method(print, myClass) in my NAMESPACE file.

S3 method help (roxygen2)

The bug you are seeing is mostly likely caused because the list method of the common generic is not being exported, so common.default gets called instead. You can pick up this problem using devtools::missing_s3 - the function is a bit heuristic, so you may get a few false positives (e.g. it can't currently tell that is.list isn't a method). This is an incredibly common problem (it has caught me so many times), and the next iteration of roxygen will do more to prevent it.

Currently, to correctly export S3 methods with roxygen you need to do either:

• @S3method generic class (and nothing else) if you don't want to document the method
• @method generic class and @export if you want to export and document it.

You should never have @S3method and @method in the same documentation block.

Update for roxygen2 >3.0.0

Now roxygen automatically figures out if a function is an S3 method so:

• Never use @S3method or @method
• Use @export if you want the method to be exported (which you normally do, even if the generic isn't)

R package documentation: Found the following apparent S3 methods exported but not registered

I don't know Roxygen2 very well, but it appears that you have declared is.nan.data.frame to be the is.nan method for class data.frame. Since you did that, you should call it as is.nan(df) in the help page example.

If you don't want it to be the method, you just want it to be a regular function using dots in the name, then you shouldn't have @method is.nan data.frame. But you indicate that you do want it to be a method.

Edited to add: Just to summarize your comments, the following fixes got rid of all the errors:

• use @export by itself without naming the function (as suggested by @KonradRudolph)
• remove the @usage line
• use is.nan(df) in the example (as I suggested)

Roxygen thinks a function of mine is an S3 method, and so breaks upon installation of my package

Fixed it!

Using @export extract.sig.metadata instead of @export apparently tells roxygen that extract.sig.metadata is the entire function name, and this fixes the problem. In this particular case, I didn't have a generic extract function, but R.utils (a package that my package did not depend upon but was nevertheless loaded) did have an extract function.

Hope this helps anyone with the same problem in the future. Thanks!

P.S. Hadley suggests better naming practices, which I will attempt to follow in the future.

Exporting data in Roxygen2 so that they are available without requiring data()

In the DESCRIPTION file of your package make sure that there is a field called LazyData that is set to TRUE.

From the "Writing R Extensions" guide:

The ‘data’ subdirectory is for data files, either to be made available
via lazy-loading or for loading using data(). (The choice is made by
the ‘LazyData’ field in the ‘DESCRIPTION’ file: the default is not to
do so.)

I think the exact syntax changed with R version 2.14; before that it was LazyLoad not LazyData.

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