cratefield-text-guard

Keeps the facts when a model rewrites text. Finds the spans a rewrite must not change (names, numbers, quotes, code, links, hashtags, and any the caller adds), then checks a rewrite against its original and lists every span it dropped or altered, and every number it made up.

use cratefield_text_guard::{SpanKind, extract, verify};

let original = "Our Q3 revenue grew by 18% to $4.2M, Dana Okafor said.";
assert_eq!(extract(original).len(), 4); // Q3, 18%, $4.2M, Dana Okafor

assert!(verify(original, "Dana Okafor says Q3 revenue rose 18% to $4.2M.").is_ok());
assert!(verify(original, "Dana Okafor says Q3 revenue rose 19% to $4.2M.").is_err());

Kind	Found as	Must survive as
`code`	fenced blocks, then inline backtick runs	verbatim, fences included
`quote`	`"…"`, `“…”`, `„…“`, `«…»` within a paragraph, at most 600 chars	the quoted words (marks may change style; a closing `,.;:` may move)
`number`	currency sign + digits joined by `.,:/-`, `%`/`‰` and glued letters (`$4.2M`, `18%`, `3rd`); capitals glued to digits (`Q3`, `FY2024`, `GPT-4`)	verbatim, at a word boundary
`name`	two or more capitalised words, lowercase particles (`of`, `van`, …) between them, leading function words dropped	verbatim, at a word boundary
`url`	`http://`, `https://` or bare `www.` links, to whitespace; trailing `.,;:!?'` and unmatched `)` `]` are the sentence's, balanced parentheses stay	verbatim and whole (not a prefix of a longer link)
`hashtag`	`#` + letters, digits, `_` in any script, at least one letter, not glued to a word (`C#`); `#123` and `# Heading` are not hashtags	verbatim, not the front of a longer tag
`custom`	byte ranges the caller supplies, labelled (`Guard::with_extra`, `extract_with`, `verify_with`)	as a caller span of the rewrite with the same label and text (an escaped copy is not one)

Rules run in the order code, quote, url, hashtag, number, name, after the caller's spans, and a span never overlaps an earlier one: the digits of a link are not numbers, a # in a link is not a hashtag, and a caller span beats any built-in span it overlaps.

A number in the rewrite that is not in the original is reported as introduced, so a changed figure shows up as one missing and one introduced. The heuristics are character scans with no regex, dictionary or model, on purpose: their limits are listed in the crate docs. Pure text, no I/O, no cratefield-core; builds for wasm32-unknown-unknown.

Platform markup the crate should not know about, such as a LinkedIn mention @[Name](urn:li:organization:123), is locked by the caller:

use cratefield_text_guard::{ExtraSpan, Guard};

fn mentions(text: &str) -> Vec<ExtraSpan> {
    // each `@[...](...)` in `text`, as ExtraSpan::new(range, "mention")
    todo!()
}

let guard = Guard::new().with_extra(mentions);
// extract, verify and ranges now run `mentions` on both texts first;
// a missing mention comes back with `span.kind_name() == "mention"`.

Pair it with cratefield-text-diff, which takes the ranges from Guard::ranges and keeps them whole in a word diff.

cratefield-text-guard 0.1.0

cratefield-text-guard