[Rd] utils::isS3stdGeneric chokes on primitives and identity

[Gabriel Becker]

Hi all,

I have a patch that fixes this and also fixes/improves debugcall so that it
supports pkg::fun(obj) and pkg:::fun(obj) style calls. I'm going to test it
a bit more and add a regression test for isS3stdGeneric and then I will
submit it to bugzilla tonight or tomorrow morning.

Best,
~G

On Thu, Aug 27, 2020 at 5:28 PM Gabriel Becker <gabembecker using gmail.com>
wrote:

> Trace adds something to the body of the function, so it does make sense
> that it doesn't. Whether traced functions still technically meet the
> definition of standard s3 generic or not is, I suppose, up for debate, but
> I would say that they should, I think.
>
> As before, if desired I can work on a patch for this if desired, or
> someone on R-core can just take care of it if that is easier.
>
> Best,
> ~G
>
> On Thu, Aug 27, 2020 at 11:22 AM Antoine Fabri <antoine.fabri using gmail.com>
> wrote:
>
>> Should it work on traced functions ?
>>
>> As it is now it doesn't.
>>
>> Best,
>>
>> Antoine
>>
>> Le jeu. 20 août 2020 à 09:58, Kurt Hornik <Kurt.Hornik using wu.ac.at> a
>> écrit :
>>
>>> >>>>> Gabriel Becker writes:
>>>
>>> > I added that so I can look at the proposed fix and put it or something
>>> > similar in bugzilla for review final review.
>>>
>>> > Apologies for the oversight.
>>>
>>> Fixed now with
>>>
>>> -    while(as.character(bdexpr[[1L]]) == "{")
>>> +    while(is.call(bdexpr) && (as.character(bdexpr[[1L]]) == "{"))
>>>
>>> (the suggested fix does not work on things like
>>> foo <- function(x) {{ x }}
>>> ...)
>>>
>>> Best
>>> -k
>>>
>>> > ~G
>>>
>>> > On Wed, Aug 19, 2020 at 3:40 PM Antoine Fabri <antoine.fabri using gmail.com
>>> >
>>> > wrote:
>>>
>>> >> Dear R-devel,
>>> >>
>>> >> utils::isS3stdGeneric tries to subset the body of the function it's
>>> fed,
>>> >> primitives don't like that because they don't have a body, identity
>>> doesn't
>>> >> like it either because it's body is a symbol.
>>> >>
>>> >> According to the doc, any function is a legal input.
>>> >>
>>> >> See below:
>>> >>
>>> >> identity
>>> >> #> function (x)
>>> >> #> x
>>> >> #> <bytecode: 0x0000000013d6da28>
>>> >> #> <environment: namespace:base>
>>> >>
>>> >> max
>>> >> #> function (..., na.rm = FALSE)  .Primitive("max")
>>> >>
>>> >> isS3stdGeneric(identity)
>>> >> #> Error in bdexpr[[1L]]: objet de type 'symbol' non indiçable
>>> >>
>>> >> isS3stdGeneric(max)
>>> >> #> Error in while (as.character(bdexpr[[1L]]) == "{") bdexpr <-
>>> >> bdexpr[[2L]]: l'argument est de longueur nulle
>>> >>
>>> >> Here is a simple fix :
>>> >>
>>> >> isS3stdGeneric <- function(f) {
>>> >> {
>>> >> bdexpr <- body(f)
>>> >> if(is.null(bdexpr) || !is.call(bdexpr)) return(FALSE)
>>> >> while (as.character(bdexpr[[1L]]) == "{") bdexpr <- bdexpr[[2L]]
>>> >> ret <- is.call(bdexpr) && identical(bdexpr[[1L]], as.name
>>> >> ("UseMethod"))
>>> >> if (ret)
>>> >> names(ret) <- bdexpr[[2L]]
>>> >> ret
>>> >> }
>>> >> }
>>> >>
>>> >> isS3stdGeneric(identity)
>>> >> #> [1] FALSE
>>> >> isS3stdGeneric(max)
>>> >> #> [1] FALSE
>>> >>
>>> >> Best,
>>> >>
>>> >> Antoine
>>> >>
>>> >> [[alternative HTML version deleted]]
>>> >>
>>> >> ______________________________________________
>>> >> R-devel using r-project.org mailing list
>>> >> https://stat.ethz.ch/mailman/listinfo/r-devel
>>> >>
>>>
>>> >       [[alternative HTML version deleted]]
>>>
>>> > ______________________________________________
>>> > R-devel using r-project.org mailing list
>>> > https://stat.ethz.ch/mailman/listinfo/r-devel
>>>
>>

	[[alternative HTML version deleted]]