dtrexp (Ruby)
This gem name is held by the DTRExp project; the Ruby port is in development and will replace this placeholder.
DTRExp (read: "DTR Expression") is a compact string expression for date-time ranges and recurrence, evaluated by coverage rather than enumeration — what cron can't say and RRULE can't answer in O(1). The spec, the shared test vectors, and the existing implementations (TypeScript, Python, Go, Swift, Rust, Java, WASM) live at DTRExp/dtrexp.
License
MIT — © 2026, Onur Yıldırım.