> On 8/05/2023, at 11:58 PM, Duncan Murdoch <murdoch.dun...@gmail.com> wrote:
>
> There really isn't such a thing as "a function that looks like an S3 method,
> but isn't". If it looks like an S3 method, then in the proper circumstances,
> it will be called as one.
>
I disagree - that was the case in old versions, but not anymore. The whole
point of introducing namespaces and method registration was to make it clear
when a function is a method and when it is a function. If you export a function
it won't be treated as a method:
In a package NAMESPACE:
export(foo.cls)
package R code: foo.cls <- function(x) "foo.cls"
in R:
> cls=structure(1,class="cls")
> foo=function(x) UseMethod("foo")
> foo(cls)
Error in UseMethod("foo") :
no applicable method for 'foo' applied to an object of class "cls"
> foo.cls(cls)
[1] "foo.cls"
So R knows very well what is a method and what is a function. If you wanted it
to be a method, you have to use S3method(foo, cls) and that **is** different
from export(foo.cls) - quite deliberately so.
Cheers,
Simon
> In your case the function name is levels.no, and it isn't exported. So if
> you happen to have an object with a class inheriting from "no", and you call
> levels() on it, levels.no might be called.
>
> This will only affect users of your package indirectly. If they have objects
> inheriting from "no" and call levels() on them, levels.no will not be called.
> But if they pass such an object to one of your package functions, and that
> function calls levels() on it, they could end up calling levels.no(). It all
> depends on what other classes that object inherits from.
>
> You can test this yourself. Set debugging on any one of your functions, then
> call it in the normal way. Then while still in the debugger set debugging on
> levels.no, and create an object using
>
> x <- structure(1, class = "no")
>
> and call levels(x). You should break to the code of levels.no.
>
> That is why the WRE manual says "First, a caveat: a function named gen.cl
> will be invoked by the generic gen for class cl, so do not name functions in
> this style unless they are intended to be methods."
>
> So probably the best solution (even if inconvenient) is to rename levels.no
> to something that doesn't look like an S3 method.
>
> Duncan Murdoch
>
> On 08/05/2023 5:50 a.m., Ulrike Groemping wrote:
>> Thank your for the solution attempt. However, using the keyword internal
>> does not solve the problem, the note is still there. Any other proposals
>> for properly documenting a function that looks like an S3 method, but isn't?
>> Best, Ulrike
>> Am 05.05.2023 um 12:56 schrieb Iris Simmons:
>>> You can add
>>>
>>> \keyword{internal}
>>>
>>> to the Rd file. Your documentation won't show up the in the pdf
>>> manual, it won't show up in the package index, but you'll still be
>>> able to access the doc page with ?levels.no <http://levels.no> or
>>> help("levels.no <http://levels.no>").
>>>
>>> This is usually used in a package's deprecated and defunct doc pages,
>>> but you can use it anywhere.
>>>
>>> On Fri, May 5, 2023, 06:49 Ulrike Groemping
>>> <ulrike.groemp...@bht-berlin.de> wrote:
>>>
>>> Dear package developeRs,
>>>
>>> I am working on fixing some notes regarding package DoE.base.
>>> One note refers to the function levels.no <http://levels.no> and
>>> complains that the
>>> function is not documented as a method for the generic function
>>> levels.
>>> Actually, it is not a method for the generic levels, but a standalone
>>> internal function that I like to have documented.
>>>
>>> Is there a way to document the function without renaming it and
>>> without
>>> triggering a note about method documentation?
>>>
>>> Best, Ulrike
>>>
>>> --
>>> ##############################################
>>> ## Prof. Ulrike Groemping
>>> ## FB II
>>> ## Berliner Hochschule für Technik (BHT)
>>> ##############################################
>>> ## prof.bht-berlin.de/groemping <http://prof.bht-berlin.de/groemping>
>>> ## Phone: +49(0)30 4504 5127
>>> ## Fax: +49(0)30 4504 66 5127
>>> ## Home office: +49(0)30 394 04 863
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>>>
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