Crater Browser (Experimental)

An highly experimental TUI browser implemented in MoonBit from scratch.

Warning: This is an experimental implementation and is not intended for production use.

Features

• HTML parsing and rendering
• External CSS fetching and application
• [ ] Sixel graphics output (with --sixel flag)
• TUI text mode rendering (with --text flag)
  • Image placeholders with alt text display
  • Gray background with borders for image areas
• Basic keyboard navigation
• [ ] Link navigation with Tab/Shift+Tab

Installation

npm install -g @mizchi/crater-browser

Usage

npx @mizchi/crater-browser <URL> [--sixel] [--debug]

Usage Example

npx @mizchi/crater-browser https://www.cnn.co.jp/fringe/35129835.html

Options

• --text: TUI text mode (default)
• --sixel: Sixel graphics mode (requires sixel-capable terminal)
• --debug: Print layout tree for debugging

Development

cd browser
moon run src/main --target js -- https://example.com
moon run src/main --target js -- --sixel https://example.com
moon run src/main --target js -- --debug https://example.com

Key Bindings

Navigation

• j / Down: Scroll down
• k / Up: Scroll up
• Ctrl-D / PageDown: Page down (scroll by one screen)
• PageUp: Page up (scroll by one screen)
• H / Backspace / Delete: Go back to previous page
• L: Go forward to next page

Links

• Tab / n: Next link
• Shift+Tab / N / p: Previous link
• Enter: Activate focused link
• f: Hit-a-hint mode (shows labels on links, type to navigate)

General

• g: Go to URL (opens prompt)
• r: Reload current page
• q: Quit
• Escape: Exit hint mode

Hit-a-Hint Mode

Press f to enter hint mode. All visible links will be labeled with characters (a-z). Type the label to navigate to that link. Press Escape to cancel.

For pages with more than 26 links, two-character labels (aa, ab, etc.) are used.

Limitations

• JavaScript is not executed
• Only a subset of CSS properties are supported
• Images shown as placeholders (not actual image rendering in TUI mode)
• Some CSS layout features (grid, advanced flexbox) are partial

TODO

• [ ] Static asset cache
• [ ] Show visited/unvisited link colors
• [ ] Tab text focus and preview
• [ ] Fix j/k scroll layout
• [ ] Access and scroll to content by AOM (Accessibility Object Model)
• [ ] Text search (Ctrl+F)
• [x] Hit-a-hint (implemented)
• [ ] Mouse click link navigation (WIP - hit testing not working correctly)