Ned

An embeddable code editor built with Dear ImGui. Runs standalone (GLFW + OpenGL/Vulkan) or embedded as a static library inside other ImGui applications.

Features: Tree-Sitter syntax highlighting, LSP integration, AI agent with MCP tools, terminal emulator, multi-cursor editing, git integration.

Architecture

Service Ownership

NedContext owns all top-level services. Leaf components receive dependencies through constructors and cannot access NedContext at runtime.

NedContext (composition root)
 ├── Settings       — themes, fonts, configuration
 ├── LSPServices    — LSP client, goto-def, goto-ref, symbol info, dashboard
 ├── FileServices   — file explorer, tree, finder, content search
 ├── AppServices    — font, keybinds, welcome, terminal, debug console
 ├── AIAgent        — chat agent, MCP tools, tab completion, editor diff
 ├── Editor         — text editing (14 sub-components, 6 state structs)
 ├── EditorEvents   — typed signal bus for cross-service communication
 └── NedCallbacks   — host engine callback interface

Constructor Injection

Components declare exactly what they need.

// Each sub-component takes only the services it uses
EditorKeyboard(AIAgent& ai, FileServices& files, Settings& settings, LSPServices& lsp, AppServices& app);
EditorCursor(Settings& settings, FileServices& files);
EditorScroll(AIAgent& ai);

Event Bus

Services communicate across boundaries using typed signals. Emitters don't know who listens.

// FileExplorer emits after opening a file
events.fileOpened.emit(path, document);

// Editor subscribes in its constructor
connFileOpened = events.fileOpened.connect([this](const std::string& path, DocumentState& doc) {
    highlight.highlightContent(doc, false, true);
    lineNumbers.setCurrentFilePath(path);
    tabs.onFileOpened(path, cursor_state, scroll);
});

// Editor disconnects in its destructor
events.fileOpened.disconnect(connFileOpened);

Signals: fileOpened, fileContentChanged, fileReloaded, folderOpened, navigateToLocation, themeChanged, consoleToggleRequested, closePopupsRequested, projectChanged

Editor State

Six private state structs owned by Editor, passed as function parameters:

Struct	Contents
DocumentState	File content, syntax colors, line positions
CursorState	Cursor position, multi-cursor list
SelectionState	Selection ranges, multi-selection
ScrollState	Scroll position, visibility flags
LayoutState	Dimensions, margins, line height
EditorSignals	Frame flags (input blocked, text changed)

Only host-layer entry points (NedApp, NedEmbed, NedEditorLayer) access state structs directly via friend access.

Embedding

Standalone: main.cpp -> NedApp -> GLFW window + render loop.

Embedded: Host creates NedEmbed with options and calls render() each frame:

NedCallbacks provides the bridge between the AI agent's MCP tools and the host engine (entity manipulation, asset queries, script building, viewport capture).

Thread-Local Context

GetNedContext() / SetNedContext() in globals.h exists for a few cases:

1. Async threads (git, highlighting, LSP goto) set the thread-local so they can access services
2. Bootstrap during initialization

Regular code uses constructor-injected references.

Build

• ned — standalone executable (GLFW + OpenGL/Vulkan)
• ned_embed — static library (no window deps)

Build flags: NED_BUILD_WITH_GLFW, NED_BUILD_WITH_VULKAN, NED_BUILD_WITH_OPENGL, NED_BUILD_WITH_CURL, NED_BUILD_WITH_GIT, NED_BUILD_WITH_FREETYPE