How to properly document a S3 method of a generic from a different package, using Roxygen?

Update

As of roxygen2 > 3.0.0 the package has gotten a lot smarter at figuring all this out for you. You now just need the @export tag and roxygen will work out what kind of thing you are documenting and do the appropriate thing when writing the NAMESPACE etc during conversion.

There are exceptions where you may need to help out roxygen. An example that Hadley Wickham uses in his R Packages book is all.equal.data.frame. There is ambiguity in that function name as to what is the class and what is the generic function (all, all.equal, or all.equal.data)?

In such cases, you can help roxygen out by explicitly informing it of the generic and class/method, e.g.

@method all.equal data.frame

The original answer below explains more about the older behaviour if you need to explicitly use @method.

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Original

The function should be documented with the @method tag:

#' @method print surveyor

On initial reading, @hadley's document was a little confusing for me as I am not familiar with roxygen, but after several readings of the section, I think I understand the reason why you need @method.

You are writing full documentation for the print method. @S3method is related to the NAMESPACE and arranges for the method to be exported. @S3method is not meant for documenting a method.

Your Rd file should have the following in the usage section:

\method{print}{surveyor}(x, ...)

if this works correctly, as that is the correct way to document S3 methods in Rd files.

As of roxygen2 > 3.0.0., you only need @export because roxygen can figure out that print.surveyor is an S3 method. This means that you now only need

#' Prints surveyor object.
#' 
#' @param x surveyor object
#' @param ... ignored
#' @export
print.surveyor <- function(x, ...){
    cat("Surveyor\n\n")
    print.listof(x)
}

However, in this case since the documentation isn't very useful, it'd probably better to just do:

#' @export
print.surveyor <- function(x, ...){
    cat("Surveyor\n\n")
    print.listof(x)
}