craft-libs/crates/proof

craft-proof

Proofing for the Craft apps, per language: spelling, suggestions, grammar checks and hyphenation, a Hunspell .aff/.dic reader, user words, ignored words and a dictionaries folder. It moved here from WordCraft's wordcraft-proof with its history and the same public API. No unsafe, no panics on hostile input, and it builds for wasm32-unknown-unknown.

craft-proof = { git = "https://github.com/storytold/craft-libs", rev = "<commit>" }

Languages

Language	Spelling	Grammar	Hyphenation
English (en-US, en-CA, en-GB and the British-spelling Englishes such as en-AU, en-NZ)	SCOWL 2026 Hunspell dictionary per English + en-extra.txt, dialect policy (en-variants.txt); a dictionaries-folder English first; without SCOWL the installed Hunspell English, else the built-in Moby list (below)	yes	Moby list, our patterns, heuristic
Polish, Portuguese, Italian	the installed Hunspell dictionary	yes	TeX patterns
Croatian, Turkish, Russian, Czech, Indonesian, Spanish (es, es-MX, es-419, es-UY)	the installed Hunspell dictionary (Russian also ru-extra.txt)	yes	Turkish and Russian rules; English fallback otherwise
German	—	—	TeX patterns
Bulgarian	—	—	syllable rules

Grammar rules, suggestion tuning and the rule-based hyphenation are code: they work in every build.

Use

use craft_proof::{ProofLang, check_text_with, suggest_in, Options};
use craft_proof::hyphen::{hyphen_points_in, Limits};

// A paragraph whose runs are in different languages (byte ranges of `text`).
let issues = check_text_with(text, &[(0..text.len(), ProofLang::EnGb)], &Options::default(), true, false);
let fixes = suggest_in("colour", 5, ProofLang::En);
let breaks = hyphen_points_in("hyphenation", &Limits::default(), ProofLang::En);

Hunspell dictionaries are not bundled; they are read from, in order: the folder given to set_dictionaries_folder, WORDCRAFT_DICTIONARIES, WordCraft's own folder under the user's application data (%LOCALAPPDATA%\WordCraft\dictionaries and %APPDATA%\WordCraft\dictionaries, ~/Library/Application Support/WordCraft/dictionaries, $XDG_DATA_HOME/wordcraft/dictionaries), then the usual Hunspell and LibreOffice locations. None on the web.

State is process-wide: add_word, ignore_word, set_dictionaries_folder, load_user_dictionary/save_user_dictionary. The crate reads no document model; callers pass plain text and language spans.

Language data

The word lists and patterns live in craft-i18n (language-data/), not here. build.rs embeds them at build time:

• CRAFT_I18N_DIR=<absolute path to a craft-i18n checkout> embeds language-data/.
• Unset (a fork, docs.rs, offline): the crate builds with a warning and no embedded Language data. English spelling then falls back as below, hyphenation that needs the data is off, and grammar and the Hunspell languages work as before.
• CRAFT_I18N_REQUIRED=1 (releases) makes a missing directory or file an error.

Tests that pin results of the data run only when every file is embedded (craft_proof_data); src/no_data.rs runs every public entry point when none is (craft_proof_no_data). A partial data folder runs neither set.

English is always checked

English spelling uses the first of these that is there; english_source(lang) says which.

1. Dictionaries folder: the English's own .aff/.dic pair (en_US, en_GB or en_CA) that the user put in the folder set with set_dictionaries_folder, in WORDCRAFT_DICTIONARIES or in WordCraft's own dictionaries folder. The user's choice comes first.
2. Installed English pack: reserved for Language packs (craft-libs#485, CP4.2).
3. Embedded SCOWL: the English's own SCOWL rel-2026.02.25 Hunspell dictionary from CRAFT_I18N_DIR (language-data/en-us, en-gb (British -ise) or en-ca, spelling.aff + spelling.dic), read by the affix engine. en-AU, en-NZ, en-IE and the other British-spelling Englishes read en-GB; Canadian English reads en-CA. A word is right when the English's own dictionary knows it (or en-extra.txt does), never because another English's does (colourblind is wrong in en-US, colorblind in en-GB); suggestions come from the same dictionary. SCOWL's size-60 lists keep one spelling per dialect, and Word accepts more, so British English also takes the -ize spellings of its -ise words that American or Canadian English spell so (organize, realization; never wize or advize), and en-variants.txt flags the other dialect's spellings and accepts this dialect's other spellings of known words (judgement in en-US). English with no dialect (is_correct) takes a word any of the three knows. Suggestions offer a missing space only between two lower-case words of three letters or more, after every one-word candidate, and no name or abbreviation (Col) for a lower-case word. With SCOWL embedded the system locations aren't searched.
4. System Hunspell: the English's own pair in the system locations. Never another English's: an en_US dictionary would mark British spellings, so en-GB and en-CA without their own use the built-in list, which has both spellings. Each name is looked for in every folder before the next name; a file that can't be read is skipped for the next name or folder; one file is read once for every English that uses it. COMPOUNDRULE, ONLYINCOMPOUND and COMPOUNDMIN (ordinals such as 21st) are read; flag-based compounding (COMPOUNDFLAG…) and OCONV are ignored for English rather than refused. None on the web.
5. Built-in list: data/en-words.dic, the whole Moby word list (about 165,000 words, 344 KB compressed, words only) built into the crate, with data/en-extra.txt (WordCraft's supplement of modern words, a copy of craft-i18n's) and the inflection rules. A word it doesn't know is misspelled. Suggestions are the words one edit away (swap, missing, added or changed letter), looked up in the list, for words of up to 32 letters: swaps first, then common words, neighbouring keys, the same first letter.

The embedded Moby list (language-data/en-us/en-us.dic) is no longer a spelling source: it is the same list as the built-in one, and stays as the hyphenation word list. en-variants.txt applies to every source above when it is embedded.

A dictionary that is there but can't be read (encoding, size, parse error, no words) is skipped, and dictionary_load_error(lang) gives the reason; it never panics. Text in other languages is never checked against English: a language without its dictionary has no spelling marks.

data/en-words.dic is public domain: the Moby Hyphenator II list by Grady Ward (Project Gutenberg eBook #3204), from craft-i18n's language-data/en-us/en-us.dic with its break points dropped and a few entries that are far more often typos left out (teh, abd, nad, ur, u, r; the list is in the generator). Regenerate with cargo run -p craft-proof --example en_words -- <craft-i18n>/language-data/en-us/en-us.dic crates/proof/data/en-words.dic. data/en-extra.txt is WordCraft contributors' own list (MIT OR Apache-2.0); keep it in step with craft-i18n's copy.

The SCOWL notice (SCOWL's licence, the Ispell BSD licence of the affix files and Benjamin Titze's notice) is embedded with the dictionaries: craft_proof::scowl::notice(), for an About window.

Embedding SCOWL adds 1,542,396 bytes of Language data (the en-US, en-GB and en-CA .aff/.dic and the notice); the Moby list (432,905 bytes) stays for hyphenation.

Check

cargo fmt -p craft-proof --check
cargo clippy -p craft-proof --all-targets -- -D warnings
CRAFT_I18N_DIR=/abs/path/craft-i18n cargo test -p craft-proof
cargo test -p craft-proof   # without Language data
cargo check -p craft-proof --target wasm32-unknown-unknown

CI: .github/workflows/proof.yml.

Credits

storytold/craft-libs#30/#31 by brzuchal (Michał Marcin Brzuchalski) started the shared crate.

Owners

WordCraft maintainers: echelon, dylanmtaylor, aiongg.

Licence

MIT OR Apache-2.0. The Language data carries its own licences, recorded in craft-i18n's ATTRIBUTION.md.