Feature/svelte latex regex (#16136)

tools/server/webui/src/lib/components/app/misc/MarkdownContent.svelte

@@ -8,6 +8,7 @@
 	import rehypeKatex from 'rehype-katex';
 	import rehypeStringify from 'rehype-stringify';
 	import { copyCodeToClipboard } from '$lib/utils/copy';
+	import { preprocessLaTeX } from '$lib/utils/latex-protection';
 	import { browser } from '$app/environment';
 	import 'katex/dist/katex.min.css';
 
@@ -156,7 +157,9 @@
 
 	async function processMarkdown(text: string): Promise<string> {
 		try {
-			const result = await processor().process(text);
+			const processedText = preprocessLaTeX(text);
+
+			const result = await processor().process(processedText);
 			const html = String(result);
 			const enhancedLinks = enhanceLinks(html);
 

tools/server/webui/src/lib/utils/latex-protection.test.ts

@@ -0,0 +1,236 @@
+/* eslint-disable no-irregular-whitespace */
+import { describe, it, expect, test } from 'vitest';
+import { maskInlineLaTeX, preprocessLaTeX } from './latex-protection';
+
+describe('maskInlineLaTeX', () => {
+	it('should protect LaTeX $x + y$ but not money $3.99', () => {
+		const latexExpressions: string[] = [];
+		const input = 'I have $10, $3.99 and $x + y$ and $100x$. The amount is $2,000.';
+		const output = maskInlineLaTeX(input, latexExpressions);
+
+		expect(output).toBe('I have $10, $3.99 and <<LATEX_0>> and <<LATEX_1>>. The amount is $2,000.');
+		expect(latexExpressions).toEqual(['$x + y$', '$100x$']);
+	});
+
+	it('should ignore money like $5 and $12.99', () => {
+		const latexExpressions: string[] = [];
+		const input = 'Prices are $12.99 and $5. Tax?';
+		const output = maskInlineLaTeX(input, latexExpressions);
+
+		expect(output).toBe('Prices are $12.99 and $5. Tax?');
+		expect(latexExpressions).toEqual([]);
+	});
+
+	it('should protect inline math $a^2 + b^2$ even after text', () => {
+		const latexExpressions: string[] = [];
+		const input = 'Pythagorean: $a^2 + b^2 = c^2$.';
+		const output = maskInlineLaTeX(input, latexExpressions);
+
+		expect(output).toBe('Pythagorean: <<LATEX_0>>.');
+		expect(latexExpressions).toEqual(['$a^2 + b^2 = c^2$']);
+	});
+
+	it('should not protect math that has letter after closing $ (e.g. units)', () => {
+		const latexExpressions: string[] = [];
+		const input = 'The cost is $99 and change.';
+		const output = maskInlineLaTeX(input, latexExpressions);
+
+		expect(output).toBe('The cost is $99 and change.');
+		expect(latexExpressions).toEqual([]);
+	});
+
+	it('should allow $x$ followed by punctuation', () => {
+		const latexExpressions: string[] = [];
+		const input = 'We know $x$, right?';
+		const output = maskInlineLaTeX(input, latexExpressions);
+
+		expect(output).toBe('We know <<LATEX_0>>, right?');
+		expect(latexExpressions).toEqual(['$x$']);
+	});
+
+	it('should work across multiple lines', () => {
+		const latexExpressions: string[] = [];
+		const input = `Emma buys cupcakes for $3 each.\nHow much is $x + y$?`;
+		const output = maskInlineLaTeX(input, latexExpressions);
+
+		expect(output).toBe(`Emma buys cupcakes for $3 each.\nHow much is <<LATEX_0>>?`);
+		expect(latexExpressions).toEqual(['$x + y$']);
+	});
+
+	it('should not protect $100 but protect $matrix$', () => {
+		const latexExpressions: string[] = [];
+		const input = '$100 and $\\mathrm{GL}_2(\\mathbb{F}_7)$ are different.';
+		const output = maskInlineLaTeX(input, latexExpressions);
+
+		expect(output).toBe('$100 and <<LATEX_0>> are different.');
+		expect(latexExpressions).toEqual(['$\\mathrm{GL}_2(\\mathbb{F}_7)$']);
+	});
+
+	it('should skip if $ is followed by digit and alphanumeric after close (money)', () => {
+		const latexExpressions: string[] = [];
+		const input = 'I paid $5 quickly.';
+		const output = maskInlineLaTeX(input, latexExpressions);
+
+		expect(output).toBe('I paid $5 quickly.');
+		expect(latexExpressions).toEqual([]);
+	});
+
+	it('should protect LaTeX even with special chars inside', () => {
+		const latexExpressions: string[] = [];
+		const input = 'Consider $\\alpha_1 + \\beta_2$ now.';
+		const output = maskInlineLaTeX(input, latexExpressions);
+
+		expect(output).toBe('Consider <<LATEX_0>> now.');
+		expect(latexExpressions).toEqual(['$\\alpha_1 + \\beta_2$']);
+	});
+
+	it('short text', () => {
+		const latexExpressions: string[] = ['$0$'];
+		const input = '$a$\n$a$ and $b$';
+		const output = maskInlineLaTeX(input, latexExpressions);
+
+		expect(output).toBe('<<LATEX_1>>\n<<LATEX_2>> and <<LATEX_3>>');
+		expect(latexExpressions).toEqual(['$0$', '$a$', '$a$', '$b$']);
+	});
+
+	it('empty text', () => {
+		const latexExpressions: string[] = [];
+		const input = '$\n$$\n';
+		const output = maskInlineLaTeX(input, latexExpressions);
+
+		expect(output).toBe('$\n$$\n');
+		expect(latexExpressions).toEqual([]);
+	});
+});
+
+describe('preprocessLaTeX', () => {
+	test('converts inline \\( ... \\) to $...$', () => {
+		const input =
+			'\\( \\mathrm{GL}_2(\\mathbb{F}_7) \\): Group of invertible matrices with entries in \\(\\mathbb{F}_7\\).';
+		const output = preprocessLaTeX(input);
+		expect(output).toBe(
+			'$ \\mathrm{GL}_2(\\mathbb{F}_7) $: Group of invertible matrices with entries in $\\mathbb{F}_7$.'
+		);
+	});
+
+	test('preserves display math \\[ ... \\] and protects adjacent text', () => {
+		const input = `Some kernel of \\(\\mathrm{SL}_2(\\mathbb{F}_7)\\):
+  \\[
+  \\left\\{ \\begin{pmatrix} 1 & 0 \\\\ 0 & 1 \\end{pmatrix}, \\begin{pmatrix} -1 & 0 \\\\ 0 & -1 \\end{pmatrix} \\right\\} = \\{\\pm I\\}
+  \\]`;
+		const output = preprocessLaTeX(input);
+
+		expect(output).toBe(`Some kernel of $\\mathrm{SL}_2(\\mathbb{F}_7)$:
+  $$
+  \\left\\{ \\begin{pmatrix} 1 & 0 \\\\ 0 & 1 \\end{pmatrix}, \\begin{pmatrix} -1 & 0 \\\\ 0 & -1 \\end{pmatrix} \\right\\} = \\{\\pm I\\}
+  $$`);
+	});
+
+	test('handles standalone display math equation', () => {
+		const input = `Algebra:
+\\[
+x = \\frac{-b \\pm \\sqrt{\\,b^{2}-4ac\\,}}{2a}
+\\]`;
+		const output = preprocessLaTeX(input);
+
+		expect(output).toBe(`Algebra:
+$$
+x = \\frac{-b \\pm \\sqrt{\\,b^{2}-4ac\\,}}{2a}
+$$`);
+	});
+
+	test('does not interpret currency values as LaTeX', () => {
+		const input = 'I have $10, $3.99 and $x + y$ and $100x$. The amount is $2,000.';
+		const output = preprocessLaTeX(input);
+
+		expect(output).toBe('I have \\$10, \\$3.99 and $x + y$ and $100x$. The amount is \\$2,000.');
+	});
+
+	test('ignores dollar signs followed by digits (money), but keeps valid math $x + y$', () => {
+		const input = 'I have $10, $3.99 and $x + y$ and $100x$. The amount is $2,000.';
+		const output = preprocessLaTeX(input);
+
+		expect(output).toBe('I have \\$10, \\$3.99 and $x + y$ and $100x$. The amount is \\$2,000.');
+	});
+
+	test('handles real-world word problems with amounts and no math delimiters', () => {
+		const input =
+			'Emma buys 2 cupcakes for $3 each and 1 cookie for $1.50. How much money does she spend in total?';
+		const output = preprocessLaTeX(input);
+
+		expect(output).toBe(
+			'Emma buys 2 cupcakes for \\$3 each and 1 cookie for \\$1.50. How much money does she spend in total?'
+		);
+	});
+
+	test('handles decimal amounts in word problem correctly', () => {
+		const input =
+			'Maria has $20. She buys a notebook for $4.75 and a pack of pencils for $3.25. How much change does she receive?';
+		const output = preprocessLaTeX(input);
+
+		expect(output).toBe(
+			'Maria has \\$20. She buys a notebook for \\$4.75 and a pack of pencils for \\$3.25. How much change does she receive?'
+		);
+	});
+
+	test('preserves display math with surrounding non-ASCII text', () => {
+		const input = `1 kg の質量は
+  \\[
+  E = (1\\ \\text{kg}) \\times (3.0 \\times 10^8\\ \\text{m/s})^2 \\approx 9.0 \\times 10^{16}\\ \\text{J}
+  \\]
+  というエネルギーに相当します。これは約 21 百万トンの TNT が爆発したときのエネルギーに匹敵します。`;
+		const output = preprocessLaTeX(input);
+
+		expect(output).toBe(
+			`1 kg の質量は
+  $$
+  E = (1\\ \\text{kg}) \\times (3.0 \\times 10^8\\ \\text{m/s})^2 \\approx 9.0 \\times 10^{16}\\ \\text{J}
+  $$
+  というエネルギーに相当します。これは約 21 百万トンの TNT が爆発したときのエネルギーに匹敵します。`
+		);
+	});
+
+	test('converts \\[ ... \\] even when preceded by text without space', () => {
+		const input = 'Some line ...\nAlgebra: \\[x = \\frac{-b \\pm \\sqrt{\\,b^{2}-4ac\\,}}{2a}\\]';
+		const output = preprocessLaTeX(input);
+
+		expect(output).toBe(
+			'Some line ...\nAlgebra: \n$$x = \\frac{-b \\pm \\sqrt{\\,b^{2}-4ac\\,}}{2a}$$\n'
+		);
+	});
+
+	test('converts \\[ ... \\] in table-cells', () => {
+		const input = `| ID | Expression |\n| #1 | \\[
+			x = \\frac{-b \\pm \\sqrt{\\,b^{2}-4ac\\,}}{2a}
+\\] |`;
+		const output = preprocessLaTeX(input);
+
+		expect(output).toBe(
+			'| ID | Expression |\n| #1 | $x = \\frac{-b \\pm \\sqrt{\\,b^{2}-4ac\\,}}{2a}$ |'
+		);
+	});
+
+	test('escapes isolated $ before digits ($5 → \\$5), but not valid math', () => {
+		const input = 'This costs $5 and this is math $x^2$. $100 is money.';
+		const output = preprocessLaTeX(input);
+
+		expect(output).toBe('This costs \\$5 and this is math $x^2$. \\$100 is money.');
+		// Note: Since $x^2$ is detected as valid LaTeX, it's preserved.
+		// $5 becomes \$5 only *after* real math is masked — but here it's correct because the masking logic avoids treating $5 as math.
+	});
+
+	test('handles mhchem notation safely if present', () => {
+		const input = 'Chemical reaction: \\( \\ce{H2O} \\) and $\\ce{CO2}$';
+		const output = preprocessLaTeX(input);
+
+		expect(output).toBe('Chemical reaction: $ \\ce{H2O} $ and $\\\\ce{CO2}$');
+		// Note: \\ce{...} remains, but $\\ce{...} → $\\\\ce{...} via escapeMhchem
+	});
+
+	test('preserves code blocks', () => {
+		const input = 'Inline code: `sum $total` and block:\n```\ndollar $amount\n```\nEnd.';
+		const output = preprocessLaTeX(input);
+
+		expect(output).toBe(input); // Code blocks prevent misinterpretation
+	});
+});