Odin support

.changeset/odin-highlighting.md

@@ -0,0 +1,5 @@
+---
+"hunkdiff": patch
+---
+
+Highlight Odin source files in diff views.

package.json

@@ -94,6 +94,7 @@
   },
   "dependencies": {
     "@pierre/diffs": "1.2.2",
+    "@shikijs/langs": "4.0.2",
     "bun": "^1.3.14",
     "commander": "^14.0.3",
     "diff": "^8.0.3",

src/core/fileLanguage.test.ts

@@ -8,6 +8,11 @@ describe("custom file language registration", () => {
     expect(getFiletypeFromFileName("src/nested/foo.mts")).toBe("typescript");
   });
 
+  test("maps Odin source files to odin", () => {
+    expect(getFiletypeFromFileName("main.odin")).toBe("odin");
+    expect(getFiletypeFromFileName("src/nested/main.odin")).toBe("odin");
+  });
+
   test("preserves Pierre's built-in extension detection", () => {
     expect(getFiletypeFromFileName("foo.ts")).toBe("typescript");
     expect(getFiletypeFromFileName("foo.tsx")).toBe("tsx");

src/core/fileLanguage.ts

@@ -1,10 +1,14 @@
 import {
   getFiletypeFromFileName,
+  registerCustomLanguage,
   setCustomExtension,
   type SupportedLanguages,
 } from "@pierre/diffs";
 
-// Pierre omits these TypeScript extensions, so register them before lookups or rendering.
+// Shiki 3 does not bundle Odin, so load its current TextMate grammar through Pierre's custom path.
+registerCustomLanguage("odin", () => import("@shikijs/langs/odin"), ["odin"]);
+
+// Register extensions Pierre omits before performing language lookups or rendering.
 const HUNK_CUSTOM_EXTENSIONS: Record<string, SupportedLanguages> = {
   mts: "typescript",
   cts: "typescript",

src/ui/diff/pierre.test.ts

@@ -1,5 +1,6 @@
 import { describe, expect, test } from "bun:test";
 import { parseDiffFromFile } from "@pierre/diffs";
+import "../../core/fileLanguage";
 import type { DiffFile } from "../../core/types";
 import {
   buildSplitRows,
@@ -675,6 +676,43 @@ describe("Pierre diff rows", () => {
     }
   });
 
+  test("highlights Odin source with the registered custom grammar", async () => {
+    const metadata = parseDiffFromFile(
+      {
+        name: "main.odin",
+        contents: "package main\nmain :: proc() {}\n",
+        cacheKey: "odin-before",
+      },
+      {
+        name: "main.odin",
+        contents: 'package main\nmain :: proc() {\n  message := "hello"\n}\n',
+        cacheKey: "odin-after",
+      },
+      { context: 3 },
+      true,
+    );
+    const file: DiffFile = {
+      id: "odin-syntax",
+      path: "main.odin",
+      patch: "",
+      language: "odin",
+      stats: { additions: 2, deletions: 1 },
+      metadata,
+      agent: null,
+    };
+    const theme = resolveTheme("github-dark-default", null);
+    const highlighted = await loadHighlightedDiff(file, theme);
+    const spans = buildStackRows(file, highlighted, theme)
+      .filter(
+        (row): row is Extract<DiffRow, { type: "stack-line" }> =>
+          row.type === "stack-line" && row.cell.kind === "addition",
+      )
+      .flatMap((row) => row.cell.spans);
+
+    expect(spans.find((span) => span.text === " :: proc")?.fg).toBeDefined();
+    expect(spans.find((span) => span.text.includes('"hello"'))?.fg).toBeDefined();
+  });
+
   test("uses Shiki's bundled Catppuccin theme for Catppuccin syntax", async () => {
     const metadata = parseDiffFromFile(
       { name: "syntax.ts", contents: "const a = 1;\n", cacheKey: "catppuccin-before" },