Hi everyone,
A short note: we eventually manage to build consensus on https://github.com/ocaml/ocaml/pull/11882 and I merged it yesterday, so there will be a Dynarray module in the standard library in OCaml 5.2. Thanks @BastouP411 and @c-cube for their efforts bringing us to this point, and to the many reviewers of the latest iteration of the PR (in particular @314eter, @c-cube, @clef-men, @damiendoligez, @dbuenzli, @gadmm, @Octachron and @wiktor).
The implementation uses an indirection to get a type-safe “empty” value to use in unused elements of the support array. Hopefully we can improve on that with a safe magical implementation in the short future – but I think that the performance is good enough already.