ARCHITECTURE.md

Neon Vision Architecture Guide

High-Level Overview

Neon Vision is a native SwiftUI application targeting macOS 14.0+ (Sonoma/Tahoe). Unlike Electron editors, we rely on Apple's TextKit 2 and SwiftUI for rendering to ensure zero-latency typing.

Core Modules

1. The Editor Engine (/Core/Editor)

• Backing Store: We do not load entire files into memory strings. We use a Rope data structure (or mmap for large files >10MB) to handle inserts/deletes efficiently.
• Syntax Highlighting: Powered by TreeSitter.
  • Performance Note: Highlighting runs on a background DispatchQueue. The main thread only receives the final NSAttributedString for the visible viewport.

2. File System & Sandboxing (/Core/FileSystem)

• Security Scoped Bookmarks: To support the "Open Recent" menu in a sandboxed environment (required for App Store), we persist security-scoped bookmarks, not just file paths.
• Coordinator: All file writes go through NSFileCoordinator to prevent data races with external edits.

3. Window Management

• Multi-Window: Neon uses WindowGroup with id injection to support multiple independent editor instances. State is not shared between windows unless explicitly passed via AppDependencyContainer.

Key Challenges for Contributors

• Large Files: Editing files >100MB is currently experimental. Logic for "chunking" lines lives in LineManager.swift.
• Vim Mode: State machine located in VimInputController.swift. All key events are intercepted before they reach the standard NSTextInputClient.