R devel - Oct 2022 - R_GetCurrentEnv() not working as intended

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

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 at
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