Editor Support

The official Feng extension for VS Code provides syntax highlighting, formatting, language services, and debugging integration.

Install the Extension

Install Feng Language from the Visual Studio Marketplace.

The extension recognizes:

• .feng and .ff: Feng source files.
• .fm: Feng project or package manifests.
• .fb: Feng Bundles.
• .ft: Feng symbol tables.

CLI Path

By default, the extension launches feng from PATH. If the command is not in PATH, specify it in the VS Code settings:

{
  "feng.executablePath": "/absolute/path/to/feng"
}

You can also use a path relative to the first workspace root:

{
  "feng.executablePath": "./build/bin/feng"
}

This setting is used for both feng lsp and feng dap.

Language Services

The extension starts feng lsp when you open a Feng file. The language server currently supports:

• Diagnostics.
• Hover information.
• Code completion.
• Go to definition.
• Find references.
• Rename.

After replacing or rebuilding the CLI, run Feng: Restart Language Server from the command palette, or select the Feng LSP status item in the status bar.

Debugging

Create a Feng configuration in the Run and Debug view. The extension creates a build task for an executable project and starts the debug session with feng dap --stdio.

When generating a configuration, the extension first infers program, the working directory, and the build task from the feng.fm nearest to the current file. For manual configuration, the essential fields are:

{
  "type": "feng",
  "request": "launch",
  "name": "Debug Feng",
  "program": "${workspaceFolder}/build/macos-arm64/bin/myapp",
  "cwd": "${workspaceFolder}",
  "args": []
}

The platform directory in program must match the platform actually built on the local machine. Debugging currently uses local, non-release builds.