fix: latex block on single line

Author: Eason0729

frontend/src/lib/components/latex/Latex.svelte

@@ -13,4 +13,6 @@
 
 {#if html != null}
 	{@html html}
+{:else}
+	{text}
 {/if}

frontend/src/lib/components/markdown/lexer/latex.test.ts

@@ -62,6 +62,22 @@ describe('MarkdownParser - LaTeX Block Delimiters', () => {
 		expect(latex.content).toBe('x^2');
 	});
 
+	test('parses \\[ \\] with text before on same line', () => {
+		const markdown = 'Some text \\[ H_3 \\] more text';
+		const result = parse(markdown);
+		const latex = result.tokens[0] as LatexBlockToken;
+		expect(latex.type).toBe(TokenType.LatexBlock);
+		expect(latex.content).toBe('H_3');
+	});
+
+	test('parses \\[ \\] with complex math in middle of line', () => {
+		const markdown = '\\[ H_4 = \\\\langle 1 \\\\rangle = \\\\{0, 1, 2, 3, 4, 5\\\\} = \\\\mathbb{Z}_6 \\]';
+		const result = parse(markdown);
+		const latex = result.tokens[0] as LatexBlockToken;
+		expect(latex.type).toBe(TokenType.LatexBlock);
+		expect(latex.content).toBe('H_4 = \\\\langle 1 \\\\rangle = \\\\{0, 1, 2, 3, 4, 5\\\\} = \\\\mathbb{Z}_6');
+	});
+
 	test('parses $$ $$ block delimiter with newline', () => {
 		const markdown = '$$\ny^2 + x^2\n$$';
 		const result = parse(markdown);

frontend/src/lib/components/markdown/lexer/parsers/block-parser.ts

@@ -151,7 +151,15 @@ export function parseLatexBlock(ctx: ParseContext): BlockParseResult {
 		delimiter = '$$';
 		endDelimiter = '$$';
 	} else {
-		return { token: null, newPosition: ctx.position, regions: [] };
+		const line = peekLine(ctx.source, ctx.position);
+		const bracketPos = line.indexOf('\\[');
+		if (bracketPos !== -1) {
+			pos = ctx.position + bracketPos;
+			delimiter = '\\[';
+			endDelimiter = '\\]';
+		} else {
+			return { token: null, newPosition: ctx.position, regions: [] };
+		}
 	}
 
 	const afterDelimiter = peek(ctx.source, pos, delimiter.length + 1);
@@ -490,7 +498,7 @@ export function looksLikeBlockStart(line: string): boolean {
 		line.startsWith('>') ||
 		line.match(/^\d+\.\s/) !== null ||
 		line.match(/^[-*+]\s/) !== null ||
-		line.match(/^\\\[/) !== null ||
+		line.match(/^\s*\\\[/) !== null ||
 		line.match(/^\$\$/) !== null ||
 		isTableRow(line)
 	);