From 2e2228f9c5e131d67e55965bba6b18ba86a9258f Mon Sep 17 00:00:00 2001
From: wallpants <47203170+wallpants@users.noreply.github.com>
Date: Thu, 29 Jan 2026 14:03:47 -0600
Subject: [PATCH] fix(latex): add support for "math" codeblocks

---
 docs/features.md | 41 +++++++++++++++++++++++++++++++++++++++++
 src/renderer.ts  | 16 +++++++++++-----
 2 files changed, 52 insertions(+), 5 deletions(-)

diff --git a/docs/features.md b/docs/features.md
index 28c60e2..2aa4b84 100644
--- a/docs/features.md
+++ b/docs/features.md
@@ -97,6 +97,47 @@ Here's a simple footnote,[^1] and here's a longer one.[^bignote]
 
 ---
 
+### LaTeX / Math
+
+```
+Inline math: $E = mc^2$ and $a^2 + b^2 = c^2$
+```
+
+Inline math: $E = mc^2$ and $a^2 + b^2 = c^2$
+
+Block math with `$$`:
+
+```
+$$
+\int_0^\infty e^{-x^2} dx = \frac{\sqrt{\pi}}{2}
+$$
+```
+
+$$
+\int_0^\infty e^{-x^2} dx = \frac{\sqrt{\pi}}{2}
+$$
+
+Math code block:
+
+````
+```math
+\sum_{n=1}^{\infty} \frac{1}{n^2} = \frac{\pi^2}{6}
+```
+````
+
+```math
+\sum_{n=1}^{\infty} \frac{1}{n^2} = \frac{\pi^2}{6}
+```
+
+> [!NOTE]
+> Consumers must include KaTeX CSS for proper rendering:
+>
+> ```html
+> <link rel="stylesheet" href="katex/dist/katex.min.css" />
+> ```
+
+---
+
 ### Mermaid
 
 Take a look at [how Pantsdown's demo is built](https://github.com/wallpants/pantsdown/blob/main/docs/build.ts)
diff --git a/src/renderer.ts b/src/renderer.ts
index ad39b86..8b418f1 100644
--- a/src/renderer.ts
+++ b/src/renderer.ts
@@ -26,18 +26,24 @@ export class Renderer {
 
     code(code: string, infostring: string | undefined, sourceMap: SourceMap): string {
         const lang = /^\S*/.exec(infostring ?? "")?.[0];
-        code = code.replace(/\n$/, "") + "\n";
+        code = code.replace(/\n$/, "");
 
         const attrs: HTMLAttrs = [];
 
         if (lang === "mermaid") {
             attrs.push(["class", "mermaid-container mermaid"]);
-        } else {
-            const language = lang && hljs.getLanguage(lang) ? lang : "plaintext";
-            code = hljs.highlight(code, { language }).value;
-            code = `<code class="hljs language-${escape(language)}">${code}</code>`;
+            const result = `<pre style="position: relative;">` + code + "\n" + `</pre>`;
+            return injectHtmlAttributes(result, attrs, sourceMap);
         }
 
+        if (lang === "math") {
+            return this.latexBlock(code, sourceMap);
+        }
+
+        const language = lang && hljs.getLanguage(lang) ? lang : "plaintext";
+        code = hljs.highlight(code + "\n", { language }).value;
+        code = `<code class="hljs language-${escape(language)}">${code}</code>`;
+
         const result = `<pre style="position: relative;">` + code + `</pre>`;
         return injectHtmlAttributes(result, attrs, sourceMap);
     }