* Studio: stop currency escape from breaking inline LaTeX
The currency-escape preprocessor in studio/frontend/src/lib/latex.ts
matched the opening dollar of any $<digits>...$ span and inserted a
backslash. The result was that text like "$30^\circ$" or
"**$90 - x$**" rendered as raw characters with stray dollar signs.
Fixes#5164.
Add two helpers in front of the escape:
- hasInlineMathCloser looks for an unescaped, non-doubled closing
dollar within the same line. Bold-wrapped spans (**$X$**) are always
treated as math since LLMs use that form for bold math.
- looksLikeMathBody filters multi-token bodies that look like prose
between two currency tokens ($5 to $10, $5, $10).
Verified against 111 inputs: the issue body, common LaTeX patterns
(Greek vars, fractions, integrals, vectors, exponents), prose currency
in lists and sentences, code blocks, and headings. All pass.
* Address review feedback on PR #5170
- Drop ^ and _ from MATH_OP_RE since LATEX_CHAR_RE already short-
circuits on those before MATH_OP_RE is consulted (Gemini comment).
- Treat compact currency ranges like $5-$10 and $5/$10 as currency
rather than math. The body between the first two dollars in those
forms is "5-" or "5/", a single non-whitespace token that previously
hit the math shortcut. Extend TRAIL_PUNCT_RE to strip - and / so the
trimmed body comes back as pure currency. (Codex comment.)
- Honour __underscore-bold__ around math the same way as **-bold**.
Markdown allows both delimiters and LLMs do reach for the underscore
form. (Gemini comment.)
Verified against the existing 18 cases plus 5 new ones for the range,
slash, and underscore-bold scenarios. All pass.
* Studio: fix numeric inline math + currency-as-closer in LaTeX preprocess
Two reviewer-flagged real-world misses in the inline-math heuristic.
1) Numeric-only operator forms like $2 + 2$, $100 < 200$, $1,000 - 500$
were getting their leading $ escaped, so the renderer never saw them
as math. The body has a math op but no lone-letter variable, so the
old looksLikeMathBody required the lone-letter clause and rejected
purely numeric expressions. Add SIMPLE_MATH_RE to recognise number-
or-letter operands joined by math operators.
2) Prose like "Starts at $5 + a $10 add-on" was being treated as one
math span "5 + a " with the second currency token mistaken for the
closer. The body satisfied the math-op + lone-letter check, so the
span got accepted and the renderer ate "10 add-on". In hasInlineMathCloser,
reject any candidate $ whose next character is a digit -- that's almost
always another currency token starting, not the closer of a real math
span (math doesn't follow $ with a bare digit).
Verified via temp/pr_simulation/sim_5170_latex.mjs: 25/25 cases pass,
including the 6 reviewer numeric-math cases, 3 currency-as-closer cases,
and 16 regression checks against the originally shipped behavior.
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