TL2 for VS Code

Syntax highlighting and basic navigation for TL2 — Type Language 2.

Features

• Syntax highlighting for .tl2 files (TextMate grammar)
• Comments toggling (//, /* */)
• Bracket matching and auto-closing for [], (), <>
• Document outline / Go to Symbol (Ctrl+Shift+O) — lists every declaration:
  • structs (name = ...)
  • unions (name = | A | B ...) with constructors as children
  • aliases (name <=> ...)
  • functions (name#crc32 ... => ...)
• Go to Definition (F12 / Ctrl+Click) on any type reference — works across files in the workspace
• Hover shows declaration signature and leading // comments
• Autocompletion of all types declared in the workspace + built-in primitives
• Diagnostics: references to types that don't exist anywhere are flagged as "Unknown type". Configurable severity (see below).

Built-in types highlighted as primitives

int32, uint32, int64, uint64, float32, float64, byte, string, bool, bit, true.

Settings

• tl2.diagnostics.unknownTypes (default: "warning") — severity for references to types not declared in the workspace. Allowed values: "error", "warning", "information", "hint", "off". Set to "off" if your project mixes TL2 files with external references the extension can't see.

Running locally (development)

1. Open this folder (TL2VSCode/) in VS Code:

   code /path/to/tl/TL2VSCode
   

2. Install dependencies and compile (only needed once, and after src/ changes):

   npm install
   npm run compile
   

3. Press F5 (or Run → Start Debugging). A second VS Code window opens with [Extension Development Host] in the title — your extension is loaded there.

4. In that second window, open any .tl2 file (e.g. internal/tlcodegen/test/tls/cases.tl2). You should see syntax highlighting, Outline (Ctrl+Shift+O), and hover/Go-to-Definition.

While iterating: after editing src/extension.ts, run npm run compile (or npm run watch in a separate terminal for auto-rebuild), then Ctrl+R in the Extension Development Host window to reload it. Grammar changes (syntaxes/*.json) and package.json changes also need the window reloaded.

Installing persistently (across all VS Code windows)

Symlink the folder into your VS Code extensions directory:

ln -s /absolute/path/to/tl/TL2VSCode ~/.vscode/extensions/tl2-0.0.1

Restart VS Code. To update: pull repo, npm run compile, Developer: Reload Window.

Packaging a .vsix

npm install -g @vscode/vsce
vsce package
code --install-extension tl2-0.0.1.vsix

Replacing the icon

The icons live in icons/:

• tl2-language-light.png — dark glyph, used on light VS Code themes.
• tl2-language-dark.png — light glyph, used on dark VS Code themes.

To swap them, replace those files (or change the icon.light/icon.dark paths in package.json). SVG also works and is preferred for sharp rendering at all sizes.

The icon appears in file tabs and the Outline view. In the Explorer tree it shows up only if your selected File Icon Theme doesn't define a .tl2 icon (most don't), so usually you'll see it.

Customizing colors

The grammar only tags tokens with TextMate scope names (e.g. entity.name.type.tl2, variable.parameter.field.tl2). Colors are picked by your current color theme. Different themes color the same scope very differently, so if anything looks off — it's the theme, not the extension.

To inspect what is actually under the cursor: Ctrl+Shift+P → Developer: Inspect Editor Tokens and Scopes. You'll see both the TextMate scope and which theme rule produced the color.

If your theme paints fields and types the same color, override them just for TL2 in your User Settings (settings.json):

"editor.tokenColorCustomizations": {
  "textMateRules": [
    {
      "scope": "variable.parameter.field.tl2",
      "settings": { "foreground": "#9CDCFE" }
    },
    {
      "scope": "entity.name.type.tl2",
      "settings": { "foreground": "#4EC9B0" }
    },
    {
      "scope": "entity.name.namespace.tl2",
      "settings": { "foreground": "#DCDCAA", "fontStyle": "italic" }
    },
    {
      "scope": "comment.metadata.crc32.tl2",
      "settings": { "foreground": "#6A6A6A" }
    }
  ]
}

Scopes used by the grammar