rrdocroxygen

Roxygen link to the "[" method

In my R package, I implemented the [ (indexing) operator for my class:

#' Some title
#' @export
setMethod("[", list(x="MyClass"), function(x, i, j, ...) {
  # Some code
})

Now, in the package documentation I want to link to the manual entry for this method. I try the normal way, using methodName,className-method:

#' [[,MyClass-method]

But that just puts a left bracket outside of the \link command in the .Rd file:

[\link{,MyClass-method}

If I try to quote it in some way, I get other issues: I have tried backtick, single and double quotes, and finally doubling the bracket [[ but none of these seem to produce a link that actually works in the final PDF.

How can I cross reference a [ method using Roxygen?

Solution

  • From the "rd-formatting" vignette in roxygen2 (which you can see using vignette("rd-formatting", package = "roxygen2")):

    Links to operators or objects that contain special characters do not currently work. So to link to (e.g.) the %>% operator in the magrittr package, instead of [magrittr::%>%], you will need to use the Rd notation: \code{\link[magrittr]{\%>\%}}.

    This works for documenting [, plus other operators, including the "assign" operators/functions that use the "assign" operator, <-. For example,

    \code{\link[myPackage]{[}}
\code{\link[myPackage]{[[}}
\code{\link[myPackage]{$}}
\code{\link[myPackage]{[<-}}
\code{\link[myPackage]{[[<-}}
\code{\link[myPackage]{[levels<-}}

    all work. If you want to link to the operator of another package, replace myPackage with otherPackage.

    On the same note, the roxygen2 method of making links like, [levels<-] or [$] will not work for these kinds of links, or if they do, throw notes/warnings when using devtools::check() nonetheless.