[R-pkg-devel] Using DOTS from C API
Oh, forgot to mention. Using Rf_eval on a promise a second time does not re-evaluate the promise. It simply returns the already calculated promise value. So if that comes up, no need to worry about it.
On Mon, Aug 18, 2025, 14:26 Josiah Parry <josiah.parry at gmail.com> wrote:
*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 [[alternative HTML version deleted]]
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