Text Input Handling

[julia-script]

Handling textual input is an extremely common requirement in user interfaces—especially in terminal UIs, which are inherently text-based—and getting it right is complex. Because of this, I believe TermUi should include native text input components. Here’s my initial vision for how they might work:

---

📝 Core Features (MVP)

• Range selection & actions

  • Copy
  • Paste
  • Replace (typing or pasting over an active selection)
  • Sanitize inputs/outputs (especially stripping or escaping escape sequences so the UI doesn’t break)

• Standard shortcuts

  • e.g. Cmd+C/Cmd+V (or Ctrl+C/Ctrl+V on other platforms), Cmd+A for select-all, etc.

• Cursor movement

  • Vertical & horizontal movement that accounts for text layout

• Quick navigation

  • e.g. Cmd+↑ to jump to the first line, Cmd+← to go to the beginning of the line

• Overflow handling

  • Scroll when text exceeds the text area (support both mouse wheel and cursor keys)

---

🔧 Post-MVP (Can Wait)

• Rich text support (formatting, inline images, etc.)
• RTL (right-to-left) support
  • Im unfamiliar with the necessities of RTL for text inputs on terminals, and this library as a whole lacks support for it. I imagine it greatly impacts many features like rendering order, text selection, etc. More research is needed

---

🌟 Nice-to-Haves

• Native support for multiple cursors would be awesome
• Text completion/suggestions
• Code-input extras, like syntax highlighting
  • We may want to investigate some form of Tree-sitter integration for this

---

📚 Requirements & Dependencies

I’m aiming for a lean subset of the web’s text APIs:

• Range API
  Based on the WHATWG spec: https://dom.spec.whatwg.org/#ranges

• Selection APIs

  • Note: browsers support two APIs for text selection:

    • A simple version for plaintext inputs (https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#textFieldSelection)
    • A more complex DOM-based version (https://www.w3.org/TR/selection-api)

  • I’m considering unifying both (plaintext and DOM) to simplify and support rich text editing via contenteditable (https://html.spec.whatwg.org/multipage/interaction.html#attr-contenteditable).

• String handling

  • Right now, nodes use text: ArrayList(u8) with a NodeKind of text. I want to introduce a String primitive with codepoint-based length (e.g., based on Zig’s Unicode support rather than byte count).

---

⚠️ Potential Roadblocks

• Shortcuts
  Terminal clients often capture common clipboard keys (Cmd+C/Cmd+V or Ctrl+C/Ctrl+V) for their own commands, so TermUi may not receive them. We’ll need to pick alternatives or find workarounds, and make it the least confusing possible.