datefixR vs Grafana Mimir

datefixR standardizes inconsistently formatted dates — the kind that arrive from spreadsheets and hand-entered clinical or survey data, with mixed separators, ambiguous orders, missing components, and month names in whatever language the source used. Version 2.0.0 rewrote the parsing core in Rust, reporting over 300x throughput against previous versions through fastpath handling of common formats and parallel column processing via a cores argument. Version 2.0.1 then spent itself cleaning up after that rewrite, restoring ordinal indicator support, stopping malformed dates from being silently cast to NA, and reinstating error messages that had gone missing.

Two long arcs meet here. The first is localization: Russian, Indonesian, German, Spanish month abbreviations, and experimental Roman numeral months accumulated release by release, with full translation of user-facing messages treated as a goal rather than a bonus. The second is the migration off R for the parsing hot path — internals began moving to C++ around 1.3.1 before the Rust rewrite replaced that work entirely. The 2.0.1 regressions show the cost of that move, since behavior that was implicit in the R implementation had to be re-specified.

The Rust core is one release into stabilization and 2.0.1 was entirely regression repair, so expect further correctness fixes against pre-2.0.0 behavior before any new format support lands.