[Rd] R_GetCurrentEnv() not working as intended

[ch@riie@g@o m@iii@g oii shikokuchuo@@et]

Hi Lionel,

I had indeed seen your Bugzilla, but must have misread the R source as I thought it had already been adopted.

Thanks for sharing the workaround as well, it is interesting. As I can pass in `environment()` to my `.Call()`, I suspect there is not much difference given the call to `Rf_eval()` at the end of the workaround.

Let's hope your patch gets reviewed and adopted.

Thanks,

Charlie

November 14, 2022 8:55 AM, "Lionel Henry" <lionel using posit.co> wrote:

> Hello,
> 
> This function currently does not work when called from `.Call()`.
> This is reported with a patch at
> https://bugs.r-project.org/show_bug.cgi?id=17839
> 
> In the meantime, you can use this stopgap implementation:
> 
> https://github.com/tidyverse/purrr/blob/55c9a8ab8788d878ce9e8e80b867139e46d15395/src/conditions.c#L6
> L34
> 
> Best,
> Lionel
> 
> On 11/13/22, Charlie Gao via R-devel <r-devel using r-project.org> wrote:
> 
>> Perhaps my original question was too complicated, so I will just ask: is
>> anyone using R_GetCurrentEnv() in their C code? If so, grateful if you could
>> point me to an example where it is working for you.
>> 
>> I have searched Github and only come across a couple of trivial uses as an
>> argument to Rf_eval(), where it probably returns the global environment,
>> with the result being indistinguishable in normal use.
>> 
>> Thanks,
>> 
>> Charlie
>> 
>> October 22, 2022 12:52 AM, "Charlie Gao" <charlie.gao using shikokuchuo.net>
>> wrote:
>> 
>>> Dear all,
>>> 
>>> I am attempting to use `R_GetCurrentEnv()` to return the current
>>> environment within C code, but it
>>> seems to always return the global environment.
>>> 
>>> Specifically, I would like to use it as an argument to R_NewEnv() so it is
>>> created with the correct
>>> enclosing environment. I also have functions in the environment that
>>> reference symbols in the
>>> closure and I would also like to use `R_GetCurrentEnv()` as an argument to
>>> `SET_CLOENV()`.
>>> 
>>> My workaround at the moment is to pass `environment()` as one of the
>>> arguments to the `.Call()`.
>>> For the actual code I am referring to:
>>> 
>>> https://github.com/shikokuchuo/nanonext/blob/main/src/aio.c#L516-L535
>>> 
>>> where I am currently passing `environment()` as 'clo' whereas ideally I
>>> would be able to use
>>> `R_GetCurrentEnv()` instead.
>>> 
>>> There is an open Bugzilla report from 2020 that says `R_GetCurrentEnv()`
>>> only returns the base
>>> namespace from within a `.Call()`, however I see that the proposed patch
>>> has already been adopted
>>> in the R source.
>>> 
>>> It seems that the function was introduced (fairly) recently in R 3.6,
>>> presumably for such uses. I
>>> would like to know if this is not the case or else confirmation that this
>>> is an outstanding bug.
>>> 
>>> Thanks,
>>> 
>>> Charlie
>> 
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