feat(tui): render LaTeX as Unicode math

packages/latex/package.json

@@ -0,0 +1,25 @@
+{
+  "$schema": "https://json.schemastore.org/package.json",
+  "name": "@opencode-ai/latex",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "exports": {
+    "./markdown": "./src/markdown.ts",
+    "./plugin": "./src/plugin.ts"
+  },
+  "scripts": {
+    "test": "bun test --timeout 30000 --only-failures",
+    "typecheck": "tsgo --noEmit"
+  },
+  "dependencies": {
+    "@opencode-ai/plugin": "workspace:*",
+    "@opentui/core": "catalog:",
+    "string-width": "catalog:"
+  },
+  "devDependencies": {
+    "@tsconfig/bun": "catalog:",
+    "@types/bun": "catalog:",
+    "@typescript/native-preview": "catalog:"
+  }
+}

packages/latex/src/layout.test.ts

@@ -0,0 +1,87 @@
+import { describe, expect, test } from "bun:test"
+import { layoutMath } from "./layout"
+import { renderLatexToString } from "./render"
+
+const text = (value: string) => ({ type: "text" as const, value })
+
+describe("structured math layout", () => {
+  test.each([
+    String.raw`\sqrt{x}`,
+    String.raw`\begin{pmatrix}a&b\\c&d\end{pmatrix}`,
+    String.raw`\underbrace{abcd}`,
+    String.raw`\overbrace{abcd}`,
+    String.raw`\sum`,
+  ])("empty scripts do not change geometry: %s", (source) => {
+    for (const scripts of ["^{}", "_{}", "^{}_{}"]) {
+      expect(renderLatexToString(source + scripts)).toBe(renderLatexToString(source))
+    }
+  })
+
+  test("centers annotations over even-width brace junctions", () => {
+    expect(renderLatexToString(String.raw`\overbrace{abcd}^{n}`)).toBe([" n", "╭┴─╮", "abcd"].join("\n"))
+    expect(renderLatexToString(String.raw`\underbrace{abcd}_{n}`)).toBe(["abcd", "╰┬─╯", " n"].join("\n"))
+  })
+
+  test("raises powers above tall matrix delimiters", () => {
+    expect(renderLatexToString(String.raw`\begin{pmatrix}a&b\\c&d\end{pmatrix}^2`)).toBe(
+      ["     2", "⎛a b⎞", "⎜   ⎟", "⎝c d⎠"].join("\n"),
+    )
+  })
+
+  test("keeps piecewise values left-aligned", () => {
+    expect(renderLatexToString(String.raw`\begin{cases}x & x>0\\x^2+1 & x\le0\end{cases}`)).toBe(
+      ["⎧x       x > 0", "⎨", "⎩x² + 1  x ≤ 0"].join("\n"),
+    )
+  })
+
+  test("honors array column alignment and continuous separators", () => {
+    expect(
+      layoutMath({
+        type: "matrix",
+        environment: "array",
+        columns: "l|r",
+        rows: [
+          [text("a"), text("wide")],
+          [text("long"), text("b")],
+        ],
+      }).toString(),
+    ).toBe(["a    │ wide", "     │", "long │    b"].join("\n"))
+  })
+
+  test("preserves edge rules and double array separators", () => {
+    expect(
+      layoutMath({
+        type: "matrix",
+        environment: "array",
+        columns: "|l||r|",
+        rows: [
+          [text("a"), text("b")],
+          [text("long"), text("c")],
+        ],
+      }).toString(),
+    ).toBe(["│ a    ││ b │", "│      ││   │", "│ long ││ c │"].join("\n"))
+  })
+
+  test.each(["left", "right"] as const)("aligns continued-fraction numerators to the %s", (numeratorAlign) => {
+    const layout = layoutMath({
+      type: "fraction",
+      numerator: text("1"),
+      denominator: text("12345"),
+      bar: true,
+      numeratorAlign,
+    })
+    expect(layout.toString()).toBe([numeratorAlign === "left" ? " 1" : "     1", "───────", " 12345"].join("\n"))
+  })
+
+  test.each(["over", "under"] as const)("stretches %s braces and places annotations outside them", (position) => {
+    const layout = layoutMath({
+      type: "scripts",
+      base: { type: "brace", body: text("a + b + c"), position },
+      ...(position === "over" ? { superscript: text("n") } : { subscript: text("n") }),
+    })
+    expect(layout.toString()).toBe(
+      (position === "over" ? ["    n", "╭───┴───╮", "a + b + c"] : ["a + b + c", "╰───┬───╯", "    n"]).join("\n"),
+    )
+    expect(layout.baseline).toBe(position === "over" ? 2 : 0)
+  })
+})