mathInline serializes as `$LaTeX$` and mathBlock as an own-line `$$\n<latex>\n$$`
fence (multi-line safe), closing hand-authoring gap A18. The LaTeX still lives in
node.attrs.text; a literal `$` inside it is escaped `\$`. On the raw-HTML path
(columns/cells) math keeps the schema-HTML `<span data-type="mathInline">` /
`<div data-type="mathBlock">` form (markdown is not re-parsed inside raw HTML) —
blockToHtml gets an explicit mathBlock case and inlineToHtml a mathInline case,
sharing the mathInlineHtml/mathBlockHtml helpers with the fallbacks so the two
forms cannot drift.
Parse: mathInlineExtension (inline) + mathBlockExtension (block) are added to the
SAME dedicated marked instance introduced for canon #7 (global singleton
untouched). The inline extension uses a currency-safe PANDOC rule: an opening `$`
must not be followed by whitespace, and the closing `$` must not be preceded by
whitespace nor followed by a digit — so `$5`, `$5 and $10`, `a $5 b $6 c`, `100$`
stay literal text while `$x^2$` is math. The block extension matches a `$$` fence
line and captures multi-line LaTeX non-greedily up to the next `$$` line.
The pandoc boundary rule lives ONCE in the new math-inline.ts
(INLINE_MATH_SOURCE) and is shared by the import tokenizer (^-anchored) and the
export prose escaper (global), so parse and serialize cannot disagree about what
is math. escapeProseMath (case "text", non-code runs only) escapes ONLY the two
delimiting `$` of a span the rule WOULD match, so a would-be-math prose span like
`the set $A$` re-imports as literal text while currency `$5 and $10` is emitted
CLEAN (zero backslash churn). marked decodes `\$`→`$` on re-parse, byte-stable.
Fallbacks to the lossless schema-HTML form (all documented + tested):
mathInline → <span> when empty / whitespace-edged / multi-line / pre-existing
`\$` / trailing `\` / immediately before a digit-text sibling (renderInlineChildren
guard, so `$…$5` can't lose the node); mathBlock → <div> when the LaTeX contains
`$$`. Each fallback round-trips losslessly and byte-stably.
Code safety (guards the canon #7 regression class): codeBlock reads raw child
text and inline `code` runs are excluded from escapeProseMath, so `$5`/`$x$` in
code stay literal with no math and no backslash corruption. ReDoS-checked on
adversarial 40k-char inputs (0–1 ms).
Tests: new math.test.ts (26 cases: serialize exactness, multi-line block, `\$`
escaping, currency ×5 asserting no `\$`, prose escape, columns schema-HTML,
inline-code/codeBlock safety, fail-open). Goldens in roundtrip / markdown-converter
flipped top-level math to `$…$`/`$$…$$`; the escapeAttr-idempotence golden wraps
math in a column (still exercises escapeAttr); columns/raw-HTML math assertions
unchanged.
package vitest: 585 passed; tsc clean. git-sync: 268 passed.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
claude code agent 227