Crate tzselect_rs 

tzselect-rs — a faithful Rust port of upstream tzselect.ksh (tzdb).

tzselect.ksh (Paul Eggert, public domain) is the interactive tzdb timezone selector: it asks the user (via stderr/stdin) to identify a location — by continent→country→region, by geographic coordinates (-c), by a proleptic POSIX TZ string, or by current local time — and prints the chosen TZ value to stdout. It reads iso3166.tab (country codes→names) and zone1970.tab (the zone table), and uses several embedded POSIX-awk programs.

This crate ports that behaviour to native Rust (no shell, no awk; the POSIX-TZ grammar is hand-parsed, so there are no runtime dependencies). Like the upstream it shells out to date for the current-time displays.

Claim boundary

tzselect-rs does not define timezone policy or choose a timezone for the user. It ports the interactive selection behaviour of upstream tzselect.ksh into Rust, using the same tzdb table surfaces, and verifies representative prompt/output paths against the upstream shell oracle. It is the user-selection layer of the Rust tzdb toolchain, beside zic-rs and the producer/QA crates; it does not enter libc localtime/strftime runtime territory.

Parity contract

The deterministic oracle is LC_ALL=C.UTF-8 COLUMNS=1 tzselect (single-column select, raw-UTF-8 names, bytewise sort). The two live-clock lines (Selected time is now: / Universal Time is now:) and the interactive time/now menus are time-dependent and classified as such. Wide-terminal multi-column select layout and non-UTF-8-locale iconv transliteration are shell/terminal/locale rendering details, also classified.

Structs

Options

Parsed command-line / environment options.

Traits

Host

Host services the port needs from the environment — abstracted so the interactive driver is unit-testable and the date shell-out is injectable.

Functions

posix_tz_valid

Hand-parsed equivalent of the check_POSIX_TZ_string regex (no regex crate).

run

Run the interactive selector. Returns the process exit code; the chosen TZ is delivered via Host::out.

usage

The usage text (tzselect.ksh:54-76).