[R-pkg-devel] Using DOTS from C API

[Josiah Parry]

*Question:* what is the best way to access a DOTSXP from R's C API in a
function call.

Over at extendr (1) we'd like to be able to utilize `...` from the body of
a Rust function—with initial motivation being to support S3 generics like
print(x, ...).

I don't see any recommendations / or mention of accessing DOTSXP in WRE.
The closest I can find is from R internals (2) repo which says

"Easiest to get to with findVar(R_DotsSymbol, env) or similar."


From R's C API would this mean we would want to use something like:

findVar(R_DotsSymbol, R_GetCurrentEnv()) to get the dots pairlist from the
function's environment?


1) https://extendr.rs
2)
https://github.com/hadley/r-internals/blob/16c1d73b635ccecec8b1f396a8935a8dd96126e4/pairlists.md

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