@spezutil/lud-codec

Converts Lisan ud-Dawat text between how people type it for legacy fonts and Unicode.

Legacy LuD fonts (Al Kanz, Al-Fatemi, Kanz al-Marjaan) have no glyphs for letters such as ٹ ڈ ڑ ں ے. Users type doubled Arabic letters instead (ثث, طط, سس, …) and the font draws them as one letter.

LuD text is stored exactly as typed, tagged with the font it was typed in — never converted to Unicode in place. A caller (editor, importer) writes the typed text alongside a data-lud-font="<profileId>" attribute and renders it in that same font. toUnicode only derives a Unicode copy from that master — for search, embeddings, and Claude inputs — and that copy is never displayed and never written back over the typed text. toDisplay/toDisplayHtml go the other way: they render text that exists only as Unicode (Claude's output, pasted proper Unicode Urdu) in a legacy font, with fallback for glyphs the font can't draw.

import { toUnicode, toDisplayHtml } from "@spezutil/lud-codec";

// Stored: <span data-lud-font="al-kanz">نسس</span> — exactly as the user typed it.

toUnicode("نسس", "al-kanz");        // "نے"   — a derived copy for search/embeddings/Claude, not saved over the typed text

toDisplayHtml("نے", "al-kanz");     // "نسس"  — render Unicode-only text (e.g. Claude's reply) inside font-family: AL-KANZ

• One JSON profile per font in profiles/. al-kanz is confirmed. al-fatemi and kanz-al-marjaan are drafts (meanings assumed from Al Kanz) and are ignored unless you pass { allowDraft: true }.
• Letters a font cannot draw and has no sequence for are returned as fallback segments, which toDisplayHtml wraps in <span class="lud-fallback"> using the profile's fallbackFont.
• ـــــ (five tatweels) is preserved verbatim.
• This package ships no font files. Declare the fonts yourself with @font-face.
• New fonts: run tools/lud-font-probe, have a person confirm the meanings, add profiles/<id>.json + <id>.corpus.json, and import the profile in src/registry.ts.
• The mahadalzahrawebapi C# port reads these same files; after changing a profile, re-run its scripts/sync-lud-profiles.sh.
• registerProfile registering an id that is already in the registry replaces it — this is how the bundled al-kanz/al-fatemi/kanz-al-marjaan profiles could be overridden by a caller. getProfile/listProfiles return deep-frozen profiles, so a caller cannot mutate a returned profile object (e.g. flip status to "confirmed") to bypass the draft gate; register a new profile instead.