A three-pane terminal code editor built in Rust. Shell on the left, code editor in the middle, file tree on the right. Runs inside your existing terminal.

The shell is a real PTY. You can run cargo build, git status, or even claude inside it while your code and project files stay visible.

• Rust (1.85+)
• macOS or Linux (PTY support required, Windows not yet supported)
• A terminal emulator (iTerm2, Terminal.app, Alacritty, Kitty, etc.)

cargo install mewtui

This puts mewtui in ~/.cargo/bin/ (already in your PATH if you installed Rust via rustup). Then from any directory:

cd my-project
mewtui

The file tree automatically roots to wherever you launch from.

When the shell is focused, all keys go directly to the PTY except the global bindings above. This means:

The shell is a real terminal. Run anything: cargo, git, npm, python, claude.

Copied text goes to the system clipboard. Paste anywhere on your Mac with Cmd+V.

The file tree syncs with the shell's working directory. When you cd in the shell, the file tree updates automatically.

20 built-in themes. Cycle through them with Ctrl+T.

Powered by tree-sitter (same engine as Neovim). Supported languages:

• Rust
• JavaScript / TypeScript
• Python
• JSON
• TOML
• Go

Highlighting is automatic based on file extension.

src/
├── main.rs               # Entry point, event loop, terminal setup
├── app.rs                # App state, focus management, key dispatch
├── ui.rs                 # Ratatui rendering, three-pane layout
├── theme.rs              # 20 theme definitions
├── editor/
│   ├── mod.rs
│   ├── buffer.rs         # Rope-backed text buffer, cursor, selection
│   └── highlight.rs      # Tree-sitter syntax highlighting
├── shell/
│   ├── mod.rs
│   └── pty.rs            # PTY spawn, VTE ANSI parser, terminal screen
└── filetree/
    └── mod.rs            # Directory traversal, expand/collapse

• Rope data structure (ropey) for the text buffer. Efficient for large files and frequent edits
• VTE parser for shell output. Handles ANSI colors, cursor movement, screen clearing, 256-color and 24-bit RGB
• Tree-sitter for syntax highlighting. Incremental parsing, same quality as Neovim
• No async runtime. Uses threads + channels for PTY I/O, keeping the architecture simple
• Single AppState as source of truth. Every frame redraws from state

The app cannot damage your system. It just renders characters and manages a text buffer.

Contributions are welcome! Here's how to get started:

git clone https://github.com/meowyx/mewtui-editor
cd mewtui-editor
cargo run

1. Fork the repo and clone it locally
2. Create a feature branch (git checkout -b my-feature)
3. Make your changes and test them (cargo run)
4. Make sure it builds clean (cargo build --release)
5. Commit and push to your fork
6. Open a pull request with a clear description of what you changed and why

• New syntax highlighting languages (tree-sitter grammars)
• New themes
• Search and replace (Ctrl+F)
• Line numbers toggle
• Tab / indent support
• Mouse scroll support
• Linux testing and fixes
• Windows support (alternative to PTY)

• Keep it simple. mewtui is meant to be lightweight and focused.
• No external runtime dependencies (no tokio, no async).
• Test your changes in at least one terminal emulator before opening a PR.
• If you're adding a theme, follow the existing Theme struct format in src/theme.rs.

Open an issue with:

• What you expected to happen
• What actually happened
• Your OS, terminal emulator, and Rust version (rustc --version)

MIT