Feng Language

Feng Language provides an out-of-the-box editing experience for Feng in VS Code. After installing the extension, you get syntax highlighting, document formatting, Feng Language Server client integration for source files, Feng debugger integration through feng dap, dedicated Feng manifest support for .fm, and distinct Feng file icons for source, manifest, bundle, and symbol-table files.

Features

• Syntax highlighting: Covers common Feng keywords, strings, comments, assignment and compound operators, and basic language structures, and highlights Feng manifest sections and # comments in .fm files.
• Document formatting: Normalizes indentation, whitespace, and common syntax spacing for day-to-day editing, including compound assignment and bitwise shift operators, and aligns manifest values inside .fm sections.
• Language Server client: For Feng source files, the extension launches feng lsp through the configured Feng executable and connects it using VS Code's standard Language Client. Hover, completion, definition, references, rename, diagnostics, and later language features are now sourced from the Feng LSP capability set exposed by your installed CLI.
• Debugger integration: The extension contributes a Feng debug type that launches feng dap --stdio, derives the default program from the nearest target: "bin" project manifest when possible, falls back to scanned workspace target: "bin" manifests when generating launch.json without an active Feng source file, writes generated program and cwd entries with ${workspaceFolder}-style variables when possible, and ensures .vscode/tasks.json contains the matching Feng build task used by the default preLaunchTask.
• Language Server restart: The command palette command Feng: Restart Language Server and the Feng LSP status bar item both stop the current language server and start a fresh feng lsp process using the latest feng.executablePath setting.
• Diagnostics compatibility: If the current Feng CLI does not yet advertise any LSP capability, the extension keeps the existing check-based diagnostics path as a temporary compatibility fallback so open/save validation does not regress.
• Icon support: The extension logo and the built-in .feng/.ff, .fm, .fb, and .ft file icons all use the latest Feng document icon family when your current file icon theme does not provide a Feng-specific icon.

Supported File Extensions

• .feng and .ff for Feng source files
• .fm for Feng manifests
• .fb for Feng bundles
• .ft for Feng symbol tables

Quick Start

1. Install Feng Language from the VS Code Marketplace.
2. Open any Feng source file and syntax highlighting will be enabled automatically.
3. When you want to clean up code, run VS Code's Format Document command.
4. If you already have the Feng CLI installed, the extension will start feng lsp automatically for Feng source files. Language features are then provided by the LSP capabilities exposed by that CLI build.
5. Open Run and Debug, create a Feng launch configuration, and start debugging. When the active file belongs to a target: "bin" Feng project, the extension derives the default launch binary and build task from the nearest feng.fm; when you create launch.json from the Run and Debug view without an active Feng source file, it falls back to the workspace's discovered target: "bin" manifests.
6. If your current CLI build still exposes an empty LSP capability set, the extension will temporarily keep open/save diagnostics through the legacy check path until the server side is filled in.

To package the extension from this repository, run bash ./scripts/build_editor_extentions.sh at the repository root; the script enters editors/feng-vscode and runs npm run pack, which packages the extension through the repository-local vsce dependency.

Optional Configuration

If the feng executable is not available in your system PATH, you can configure it explicitly in VS Code settings:

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

This path can be either an absolute path or a path relative to the first workspace root.

When feng.executablePath keeps its default value, the extension runs feng directly from your system PATH.

The same executable setting is used for both feng lsp and feng dap.

Formatting Behavior

The formatter is designed to cover the most common cleanup tasks in everyday development:

• Adjust indentation around {}, (), and []
• Remove trailing whitespace at the end of each line
• Normalize line endings to \n
• Normalize binary and compound operator spacing, for example a+b → a + b, total+=1 → total += 1, mask>>=1 → mask >>= 1
• Normalize parameter and argument lists, for example func add(a:int,b:int) → func add(a: int, b: int)
• Normalize spacing around :, ,, and {} in object literals and type annotations

For .fm manifest files, the formatter additionally:

• Normalizes [section] headers
• Normalizes # comment spacing
• Aligns key: "value" entries within each section so values start in the same column

Its goal is to provide a stable and predictable formatting experience for daily use. It does not currently reflow complex expressions across lines or perform multi-line alignment.

Language Service

• Feng source files are connected through the standard VS Code Language Client by launching feng lsp.
• The default executable name is feng, resolved through your system PATH.
• If your CLI is not in the default lookup path, set feng.executablePath to the correct executable location.
• Run Feng: Restart Language Server from the command palette, or click the Feng LSP status bar item, after rebuilding or changing the configured executable.
• The extension keeps the built-in formatter and TextMate grammars; only language-service features move behind LSP.
• If the installed CLI currently reports an empty LSP capability set, the extension temporarily preserves the previous open/save diagnostics path by running feng check --format json <file> for project files and feng tool check <file> for standalone files.

Debugging

• The extension contributes a feng debug type that starts feng dap --stdio.
• On macOS, feng dap first tries lldb-dap from PATH; if that misses, it falls back to xcrun -f lldb-dap, which keeps packaged VS Code sessions working even when Xcode's debugger binaries are not exported directly in PATH.
• When a launch configuration omits program, the extension first tries to resolve it from the nearest target: "bin" project manifest by mapping name and out to <out>/<host-platform>/bin/<name>, then falls back to the unique discovered workspace target: "bin" project when no active Feng file is available.
• When a launch configuration omits preLaunchTask, the extension binds it to the generated Feng build task for that project.
• When VS Code generates a Feng launch.json, the extension also ensures .vscode/tasks.json contains the matching type: "feng" build task so the generated preLaunchTask resolves without manual setup.
• Generated program and cwd values prefer ${workspaceFolder}-style variables over absolute paths whenever the Feng project lives inside the active workspace folder.
• The current debug surface targets macOS + lldb-dap and the non-release local target=bin build path.
• evaluate currently covers the read-only subset exposed by feng dap: identifiers, member access, constant integer indexing, and simple arithmetic/comparison expressions. Function calls, assignments, and other unsupported watch expressions are rejected explicitly.