open tui c++

open tui c++ is a lightweight C++20 terminal UI library for building interactive CLI tools and debugger-like workflows.

Highlights

• Overridable banner and prompt through inheritance.
• Built-in commands: help, /help, clear, /clear, exit, /exit, quit, /quit.
• Simple command registration API with argument handlers.
• Interactive tab completion for commands and custom sub-arguments (including common-prefix expansion).
• Inline autosuggestions (dim ghost text from completion/history), accepted with Right Arrow.
• Live completion list on the bottom line while typing (e.g., typing f lists all matching commands).
• Interactive command history navigation (↑/↓) in TTY mode.
• Fine-grained colored output (ANSI, with Windows virtual terminal support).
• Signal-aware run loop for clean termination (SIGINT, SIGTERM, SIGHUP on POSIX).
• UDP send/receive utility for external agent communication.
• C++20, CMake, .clang-format, and .clang-tidy included.
• Cross-platform target: macOS, Linux (Ubuntu), and Windows.

Claude Code-style Demo

A new demo app was added to showcase a Claude Code-like terminal flow:

• shell chrome/status strip (/status)
• slash commands (/model, /theme, /attach, /files, /focus, /plan)
• argument autocomplete (model/theme/focus/plan/run starters + filesystem path completion for /attach)
• assistant-style message command (ask)
• tool run simulation command (run)
• built-in clear behavior (/clear)

Snapshot

Example snapshot included in this repository:

Build

cmake -S . -B build
cmake --build build

Run examples

# Existing debugger sample
./build/open_tui_example

# Claude Code-style sample
./build/open_tui_claude_style_example

Or via task helper:

./scripts/tasks.sh run-example
./scripts/tasks.sh run-claude-example

Lint and format

find include src examples -type f \( -name '*.hpp' -o -name '*.cpp' \) -print0 | \
  xargs -0 clang-format --dry-run --Werror

macOS (Homebrew LLVM) clang-tidy example:

SDKROOT=$(xcrun --show-sdk-path)
clang-tidy -p build src/*.cpp examples/debugger/main.cpp examples/claude_code/main.cpp \
  --extra-arg=-isysroot --extra-arg=$SDKROOT --quiet

Library usage

1. Inherit from opentui::TuiApplication.
2. Override banner() and optionally prompt(), on_start(), on_shutdown().
3. Implement register_commands(opentui::CommandRegistry&) and add commands.
4. Call run() from main().

Minimal example:

class MyApp : public opentui::TuiApplication {
protected:
  std::string banner() const override { return "my app"; }

  void register_commands(opentui::CommandRegistry& registry) override {
    registry.add(opentui::Command{
      .name = "ping",
      .description = "prints pong",
      .handler = [](const opentui::Args&, opentui::CommandContext& ctx) {
        ctx.console.println("pong");
      },
      .completer = nullptr,
    });
  }
};