Newer OpenAI chat models put metadata on the opening line of a colon fence block, like :::writing{variant="email" id="48173" subject="Short question" recipient="mail@example.com"}. The tokenizer matched that line and discarded it, so every block rendered under the same generic "Writing" heading no matter what it contained.
The opening line is now parsed into an attributes map on the token and the header uses it: the subject becomes the title, the recipient follows it and the full string is reachable on hover when the row is too narrow for it. Blocks without metadata render exactly as before, and the other fence types get the parsed attributes for free.
Attributes are read only from inside the {...} braces, not from the whole opening line. Scanning the whole line turned ordinary prose containing key="value" into metadata, and it backtracked quadratically: a 40k character opening line took 586ms to parse, and that runs again on every re-lex while the message streams. Anchored to the braces it is 0.0ms.
Nothing here turns the recipient into a link or a send action. That metadata is model output and can be steered by whatever is in the context, so a prefilled mail action is a separate decision rather than a side effect of parsing.
* perf: pre-compile KaTeX Unicode regex at module load time
The katexStart() function was creating a new RegExp with Unicode
property escapes (\p{Script=Han}, \p{Script=Hiragana}, etc.) on
every invocation. Unicode property escapes are extremely expensive
to compile as the regex engine must build character class tables
covering tens of thousands of code points.
Since marked calls the start() function at every character position
while scanning source text, this meant hundreds of regex compilations
per marked.lexer() call, and lexer runs ~60 times/sec during streaming.
Profiling showed KaTeX regex consuming 87% (320ms/365ms) of total
markdown rendering time.
Changes:
- Pre-compile SURROUNDING_CHARS_REGEX once at module load time
- Use .test() instead of .match() to avoid array allocations
- Fix delimiter search to find earliest match, not last match
* perf: replace katexStart with single-pass character scan
The katexStart() function was the dominant cost in marked's lexer,
consuming 55-58% of total markdown rendering time per profiling.
It was called at every character position by marked and each call:
- Looped through 3-5 delimiters, each doing indexOf() on the full
remaining source (3-5 x O(n) string scans per call)
- Ran the complex ruleReg regex with Unicode lookaheads for validation
- On failed validation, created substrings and looped again
Replace with a single linear character scan using charCodeAt that:
- Checks only for $ (charCode 36) or backslash (charCode 92)
- Filters backslash hits by next character to avoid false positives
- Preserves the surrounding-character validation
- Returns immediately on first valid candidate
- Lets the tokenizer handle full validation (it already does this)
This reduces start() from O(n * delimiters * retries) to O(n) with
a very small constant factor per call.
* Update katex-extension.ts
Fixes an issue where `ue.getWordAtDocPos is not a function` would be thrown in `MessageInput.svelte`.
The error was caused by a timing issue where the `getWordAtDocPos` method on the `RichTextInput` component was not available when called from an event handler within the same component.
This change refactors the code to pass the `getWordAtDocPos` function as a callback prop from `RichTextInput` to `MessageInput`, ensuring it's available when needed.
Classic298