[Rcpp-devel] Life-cycle of Rcpp::XPtr

[Ralf Stubner]

Hi Dirk,

> I had done some experiments with 'expanded finalizers' that use more logging
> (which I find quite convenient via `spdl` -- same nice spdlog interface now
> from R and C++) so you could add some display of the pointer address, check
> on nullness etc.
>
> I have done a bit more work using XPtr in the context of the tiledb (and the
> related, possibly upcoming tiledbsoma package not yet on CRAN) where I use an
> enum (which requires C++17 in the use I have there) to 'type tag' each
> external pointer and on each use check I have the correct type. I am not
> thinking to a simple unordered_map from enum to string to also make more
> informed errors (showing the type as string rather than enum int value) as
> well as maybe an enhanced show or print at the R level. I have long been
> meaning to farm that out into a new (simple) add-on package (see issue #1212)
> and should get on with that.  (The 'still somewhat raw' XPtr extension in
> tiledb is eg here:
> https://github.com/TileDB-Inc/TileDB-R/blob/1e7bd2fa4e54f3e152c4fec3a65343df49d3f525/src/libtiledb.h#L80-L160
> and the check_xptr_tag is then used throughout the files in src/.

Thanks! That does sound interesting. I think for my current use-case
the existing functionality is sufficient. But i will have a look at
these ideas.

Ralf