XETO Extension for VSCode

Overview

The XETO Extension for VSCode provides language support and code editing features for the XETO language using the Language Server Protocol (LSP).

Key Features

• Syntax highlighting - with semantic token support
• Code completion - type-aware suggestions from resolved libraries
• Go to definition - across local files and external libraries
• Hover information - inline documentation on hover
• Diagnostics - syntax errors and unresolved dependency warnings
• Props-based resolution - automatic library discovery via fan.props / xeto.props
• Context switching - reloads libraries when switching between repos
• Rename symbols - across the entire workspace
• Formatting - automatic code formatting

Environments

The extension works in both:

• Desktop environment - Full-featured VS Code
• Web environment - Compatible with vscode.dev and github.dev

Library Resolution

The extension discovers Xeto libraries using the same conventions as the Fantom/Xeto CLI tools. For most projects, no configuration is needed.

Props-Based Path Resolution

When you open a .xeto file, the extension walks up the directory tree looking for xeto.props or fan.props. If found, it parses the path= line and scans the resolved directories for libraries.

# fan.props
path=../studio;../haxall;../xeto

Paths are semicolon-separated and resolved relative to the props file directory. Each resolved directory is scanned for src/xeto/ (raw source) and lib/xeto/ (compiled xetolibs).

This is the same resolution mechanism used by xetoc and the Haxall runtime.

What Works Out of the Box

Just install and open a .xeto file. The bundled standard libraries (sys, ph, ph.equips, ph.points, ashrae.g36, etc.) are always available. If your project has a fan.props with a path= line, all referenced repos are resolved automatically.

Priority

When the same library exists at multiple levels, the highest-priority source wins:

Status Bar

The status bar shows the current resolution state:

• Xeto: fan.props (5 paths) - resolved via fan.props
• Xeto: xeto.props (3 paths) - resolved via xeto.props
• Xeto: bundled only - no props file found

Click it to see the full resolved path in the Output channel.

Dependency Diagnostics

In lib.xeto files, each entry in the depends block is checked against the resolved path. If a referenced library isn't found, a warning appears on the lib name.

Live Props Watching

When you edit a fan.props or xeto.props file, the extension automatically invalidates its cache and re-resolves. No VS Code reload needed.

External Libraries (Fallback)

For projects without a props file, you can configure library paths manually in .vscode/settings.json:

macOS / Linux:

{
  "xeto.libraries.external": [
    "/path/to/haxall/lib/xeto",
    "/path/to/other-repo/src/xeto"
  ]
}

Windows:

{
  "xeto.libraries.external": [
    "C:\\Code\\haxall\\lib\\xeto",
    "C:\\Code\\other-repo\\src\\xeto"
  ]
}

Each path is scanned for subdirectories containing a lib.xeto file (raw source) or a .xetolib file (compiled library).

Features

Syntax highlighting with semantic token support:

Go to definition across local files and external libraries:

Code completion with type-aware suggestions:

See the full feature gallery with demos in FEATURES.md.

Usage

1. Open a xeto file that has the .xeto extension
2. The XETO Extension will automatically activate and provide language features
3. Use the provided Visual Studio Code keyboard actions and/or commands

Installation

Extension Marketplace

1. Launch Visual Studio Code
2. Open the Extensions tab using Ctrl+Shift+X or ⌘+Shift+X
3. Search by using xeto
4. Install the extension

GitHub Release

1. Go to the "Releases" section
2. Download the latest release package under extension.vsix
3. Launch Visual Studio Code
4. Open the Extensions tab using Ctrl+Shift+X or ⌘+Shift+X
5. Select Install from VSIX... from the Views and More Actions menu
6. Navigate to the downloaded file and select it

Note: For detailed instructions on installing from VSIX, see the official VS Code documentation.

Contributing

We welcome bug reports, feature requests, and feedback! Please see CONTRIBUTING.md for guidelines.

License

This project is licensed under the BSD-3-Clause License. See the LICENSE for more info.