Crate edtf_normalize 

Deterministic prose-date → EDTF normalizer (GitHub issue #20).

Real people typing dates into forms need instant, offline, deterministic normalization — “1980s” → 198X on every keystroke, the same answer every time. This crate is a bounded pattern grammar over date prose: values are constructed through the edtf_core model and rendered via its canonical Display, then re-parsed, so every output is valid, canonical EDTF by construction. Anything outside the grammar is Outcome::NoMatch — never a silent guess. Genuinely ambiguous inputs (“12/04/1985”) report every reading instead of picking one.

Pattern tables are per-language (Language::English and Language::Russian today); adding a locale means adding one table struct, not touching the grammar. Every judgement call is a numbered N-decision in docs/normalize-notes.md, cited from the Note values attached to results.

use edtf_normalize::{normalize, Outcome};

let Outcome::Normalized(n) = normalize("circa 1920") else { panic!() };
assert_eq!(n.edtf, "1920~");

// "12/04/1985" is DD/MM or MM/DD — the form gets both readings, not a guess.
assert!(matches!(normalize("12/04/1985"), Outcome::Ambiguous(_)));

Structs

Ambiguous

A set of plausible readings. Always at least two; the form should ask, not pick.

Interpretation

One plausible reading of an ambiguous input.

Normalized

A successful, unambiguous normalization.

Options

Caller-supplied context. Everything is optional; the defaults never guess.

Enums

Language

Which pattern-table set to match against.

NoMatchReason

Why a Outcome::NoMatch happened — the discriminator a bulk-import triage step routes on (N11/N12).

Note

Why an output looks the way it does. Each variant cites the N-decision in docs/normalize-notes.md that governs it, so a form can explain the conversion to the person typing.

NumericOrder

Resolution order for all-numeric dates where both readings are plausible.

Outcome

The honest return type: a match, several readings, or nothing — never a silent guess.

Functions

normalize

Normalize English date prose with default options.

normalize_with

Normalize with explicit Options (language, numeric order, default century).