moonbit-community/tty

Low-level terminal primitives for MoonBit.

moonbit-community/tty provides a small foundation for programs that need to talk to a real terminal: tty detection, raw mode, terminal size queries, output commands, color values, and host input decoding. It is intentionally below a full TUI framework. It does not own a screen model, layout engine, widget tree, pane system, or scrollback buffer.

Status

This module is early and native-target focused. Public APIs are still being shaped around small terminal programs and the examples in this repository.

Packages

moonbit-community/tty

The root package owns coordinated terminal handles and stateful terminal operations.

Use Tty when an operation needs a real terminal handle:

• process stdio: Tty::stdio()
• controlling terminal: Tty::open()
• custom handles: Tty::new(input, output) with Reader and Writer traits for async files, stdio, and OS pipes
• raw mode: Tty::get_state, State::make_raw, Tty::set_state, Tty::with_raw_mode
• terminal size: Tty::window_size
• cursor position report: Tty::query_cursor_position
• kitty keyboard protocol support query: Tty::query_kitty_keyboard_support
• terminal events: Tty::read_event
• output commands: cursor movement/visibility, line erase, scroll margins, reverse index, alternate screen, bracketed paste mode, foreground/background colors, text attributes, and style reset

Raw file and stdio byte I/O should use moonbitlang/async/fs and moonbitlang/async/stdio directly. The root package does not wrap them as stdin, stdout, or stderr.

VT/ANSI byte construction is an internal implementation detail. Downstream callers should use root Tty output command methods instead of importing byte-sequence helpers directly.

moonbit-community/tty/input

User input event values.

The package contains key, paste, modifier, and unknown-input values reported through root Tty::read_event. Terminal response traffic such as cursor position reports and kitty keyboard detection replies is consumed by root query methods and is not part of the public input event model. Root callers that are working with a terminal should use Tty::read_event so input, resize notifications, and terminal request/response traffic share the same coordinated terminal handle.

moonbit-community/tty/color

Semantic terminal color values.

The package represents default, ANSI basic/bright, indexed 256-color, and RGB truecolor values. Root Tty methods turn these values into SGR output.

Usage

Add the module and import the packages you need in moon.pkg:

import {
  "moonbit-community/tty"
  "moonbit-community/tty/color" @tty/color
  "moonbit-community/tty/input" @tty/input
}

Write terminal commands through a Tty:

async fn main {
  let tty = @tty.Tty::stdio()
  tty.hide_cursor()
  tty.set_cursor_position(1, 1)
  tty.bold()
  tty.set_foreground(@tty/color.Basic(@tty/color.Green))
  tty.write("hello from tty\r\n")
  tty.reset_style()
  tty.show_cursor()
}

Run a scoped raw-mode input loop:

async fn main {
  let tty = @tty.Tty::stdio()
  tty.with_raw_mode(() => {
    tty.write("press q to quit\r\n")
    while true {
      match tty.read_event() {
        @tty.Input(@tty/input.Key(key)) =>
          match key.code {
            Char('q') => break
            _ => ()
          }
        @tty.Input(@tty/input.Paste(_)) => ()
        @tty.Input(@tty/input.Unknown(_)) => ()
        @tty.Resize(_) => ()
      }
    }
  })
}

Examples

Examples live in a separate workspace member under examples/.

moon run examples/raw
moon run examples/input
moon run examples/color
moon run examples/cursor
moon run examples/pager -- README.md
moon run examples/agent

The examples are manual validation tools, not framework APIs:

• examples/raw checks raw mode behavior.
• examples/input exercises decoded key input and grapheme-aware demo editing.
• examples/color prints a color specimen.
• examples/cursor draws with cursor movement and erase sequences.
• examples/pager demonstrates primary-screen paging with a fixed status row.
• examples/agent demonstrates a Codex-like primary-screen transcript, input composer, delayed queued input, and shell command execution.

Design Boundaries

• tty owns terminal handles, platform state, raw mode, terminal size, cursor position queries, and command-style terminal operations.
• internal VT helpers only build byte sequences for root Tty methods.
• input contains user input event values.
• internal input decoding turns host input bytes into root terminal events and private terminal response events.
• color only represents semantic color values.
• Higher-level editing, layout, widgets, screen rendering, and terminal-emulator state belong outside this module unless the project plan changes.

See docs/architecture.md and docs/plan.md for the current design notes and execution board.

Development

Common validation commands:

moon fmt
moon test .
moon test
moon check
moon info

Review pkg.generated.mbti after moon info; it is the public API surface.