Crate intl 

intl — a pure-Rust, #![no_std] analog of ICU.

The crate is always #![no_std]. The Unicode layer and several locale helpers need no allocator; the alloc feature enables the allocating APIs (most formatters). UCD and CLDR data are compiled by an offline code generator into committed tables — const fn match lookups for the Unicode properties and embedded binary blobs for the CLDR data — so lookups allocate nothing and need no runtime initialization.

Modules:

• unicode — General_Category and predicates, scripts, East Asian Width, numeric values, case mapping/folding, normalization (UAX #15), collation (UTS #10), segmentation (UAX #29), line breaking (UAX #14), bidi (UAX #9), identifiers (UAX #31), confusables (UTS #39), IDNA (UTS #46). Property tables are gated by feature-selectable codepoint ranges.
• locale — BCP-47 parsing/canonicalization, likely-subtags maximize/minimize, negotiation. (alloc)
• plural — CLDR cardinal/ordinal plural categories.
• number — decimal / percent / currency formatting. (alloc)
• datetime — Gregorian date/time formatting (styles, skeletons), ISO-8601 I/O, date arithmetic, localized GMT offsets, Islamic/Persian rendering. (alloc)
• calendar — Gregorian / Islamic / Persian / Hebrew / Japanese / ISO-week date conversions.
• relative, list, unit, message — relative-time, list, measurement-unit, and MessageFormat formatting. (alloc)
• display — locale display names (language / region).

use intl::unicode::{general_category, GeneralCategory};
assert_eq!(general_category('A'), GeneralCategory::UppercaseLetter);

Modules

calendar

Calendar date conversions (no_std, no alloc): the Julian Day Number as a pivot between the proleptic Gregorian, civil (tabular) Islamic, Persian (Solar Hijri), Hebrew, Chinese (lunisolar, 1900–2099), and Japanese-era calendars, plus the ISO-8601 week date and day of week. Pure integer arithmetic; only the Chinese calendar uses an embedded lunar table.

datetime

Locale-aware date and time formatting (CLDR / UTS #35, Gregorian). Requires the alloc feature.

display

Locale display names (CLDR / UTS #35): the name of a language or region as written in a given display locale. no_std, no alloc (results borrow from the embedded tables).

list

Locale-aware list formatting (CLDR / UTS #35): joining items with the right connectors, e.g. "a, b, and c" (English “and”) or "a, b o c" (Spanish “or”). Requires the alloc feature.

locale

BCP-47 / Unicode (UTS #35) locale identifiers.

message

A pragmatic subset of ICU MessageFormat (UTS #35 messages). Requires the alloc feature.

number

Locale-aware decimal and percent number formatting (CLDR / UTS #35). Requires the alloc feature.

plural

CLDR plural rules (UTS #35): selecting the PluralCategory for a number in a given language. The rules are compiled from CLDR into a match by the offline codegen, so selection allocates nothing and needs no runtime parsing.

relative

Locale-aware relative time formatting (CLDR / UTS #35): “in 3 days”, “2 hours ago”, “yesterday”. Requires the alloc feature.

spellout

Spelling integers out in words via the CLDR rule-based number format (RBNF). Requires the alloc feature. Locale-driven (a curated set of locales), not hardcoded for any language.

timezone

POSIX TZ-string time zones (no_std, no alloc): parse a rule string like "PST8PDT,M3.2.0,M11.1.0/2" and compute the UTC offset for any local date using its standard/DST rules. This handles the current rules of a zone without the full IANA historical database.

translit

Transliteration / transforms. Requires the alloc feature.

unicode

Unicode rune analysis driven by the official Unicode Character Database (UCD).

unit

Locale-aware measurement-unit formatting (CLDR / UTS #35): “5 kilometers”, “3 hr”, “2,5 Stunden”. Requires the alloc feature.