[R-pkg-devel] S3 method, useMethod and <-, using Roxygen

[Daniel Lüdecke]

Ok, this might be a Roxygene issue, so I would close this discussion 
here and file an issue at GitHub for further investigation. What I found 
out so far:

#' @rdname set_label
#' @export
`set_label<-` <- function(x, attr.string = NULL, value) {
   UseMethod("set_label<-")
}

#' @rdname set_label
#' @export
`set_label<-.default` <- function(x, attr.string = NULL, value) {
   x <- set_label(x, value, attr.string)
   x
}


creates following rd-file:

% Generated by roxygen2 (4.1.1): do not edit by hand
% Please edit documentation in R/set_label.R
\name{set_label}
\alias{set_label}
\alias{set_label<-}
\alias{set_label<-.default}
\alias{set_var_labels}
\title{Add variable label(s) to variables}
\usage{
set_label(x, lab, attr.string = NULL)

set_var_labels(x, lab, attr.string = NULL)

set_label(x, attr.string = NULL) <- value

\method{set_label}{default}(x, attr.string = NULL) <- value
}


while

#' @rdname set_labels
#' @export
`set_labels<-` <- function(x, force.labels = FALSE, force.values = TRUE, 
value) {
   UseMethod("set_labels<-")
}

#' @rdname set_labels
#' @export
`set_labels<-.default` <- function(x, force.labels = FALSE, force.values 
= TRUE, value) {
   x <- set_labels(x, value, force.labels, force.values)
   x
}


results in

% Generated by roxygen2 (4.1.1): do not edit by hand
% Please edit documentation in R/set_labels.R
\name{set_labels}
\alias{set_labels}
\alias{set_labels<-}
\alias{set_labels<-.default}
\alias{set_val_labels}
\title{Add value labels to variables}
\usage{
set_labels(x, labels, force.labels = FALSE, force.values = TRUE)

set_val_labels(x, labels, force.labels = FALSE, force.values = TRUE)

set_labels(x, force.labels = FALSE, force.values = TRUE) <- value

\method{set_labels}{default}(x, force.labels = FALSE, force.values = TRUE)
   <- value
}


There's a carriage return (or similar) in the generated rd-file which 
throws the warning message in the check procedure. I cam up with 
removing "#' @rdname set_labels", because 1) it works fine then and 2) 
my index-page of the package help does not list redundant function names 
multiple times.

Best
Daniel



Am 23.10.2015 um 13:10 schrieb Hadley Wickham:
> Here's a minimal reprex:
>
> out <- roc_proc_text(rd_roclet(), "
>    #' Foo
>    `foo<-` <- function(x, y, value) {
>      UseMethod('set_labels<-')
>    }
>
>    #' Foo
>    `foo<-.default` <- function(x, y, value) {
>      x
>    }
>    ")[[2]]
>
> cat(format(out))
>
> That generates
>
> \usage{
> \method{foo}{default}(x, y) <- value
> }
>
> which I believe is correct, although I don't think I've ever seen such
> a construct in the wild.
>
> Duncan: does that look right to you? (i.e. is that what the usage of
> method of a replacement function should look like?)
>
> Hadley
>
> On Fri, Oct 23, 2015 at 3:30 AM, Daniel Lüdecke <d.luedecke at uke.de> wrote:
>> Hello,
>> I don't exactly know how to name my problem, so I try to describe it.
>>
>> In my package (sjmisc), I have a function to set label attributes to
>> vectors:
>>
>> set_labels <- function(x, labels, ...) {
>> ...
>> }
>>
--

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