zen-Babel

zen-Babel is a local-first translation app for Apple platforms (macOS / iOS). It is designed for on-device translation workflows where privacy, low latency, and offline-friendly behavior matter. In version 0.8.1, the app name changed from Pre-Babel Lens to zen-Babel (Japanese name: zenバベル).

Repository: https://github.com/ttrace/pre-babel-lens

Current Direction

• Swift + SwiftUI based app architecture
• Backend-swappable translation engines
• Deterministic preprocessing + observable translation pipeline
• iOS default runtime focuses on Apple Translation framework stability
• Foundation Models path is capability-gated and used for quality improvements when available

Key Features

• On-device translation workflow (no mandatory cloud round-trip)
• Clutch mode (iOS / macOS): bidirectional segment highlighting between Source and Output
• Auto-scroll to corresponding segment when target is out of view
• macOS View controls: compact/column layout and text-size actions
• Import support:
  • macOS: drag & drop / file import (.txt, .md, .pdf, .docx, etc.)
  • iOS Share Panel: document import (.pdf, .docx)
  • Image OCR via Vision framework
• Quick Launch on macOS via double copy (Cmd+C, Cmd+C)

macOS Quick Launch by Double Copy

1. Select text in any app.
2. Press Command + C twice quickly (about 1 second).
3. zen-Babel comes to front and starts translation with the selected text.

Notes:

• macOS only.
• Empty clipboard content is ignored.
• Duplicate requests are suppressed.

Automator Integration (macOS)

You can launch translation from selected text via Automator Quick Action.

1. Create a new Quick Action in Automator.
2. Set:
   • Workflow receives current: text
   • in: any application
3. Add Run Shell Script (/bin/zsh, pass input to stdin).
4. Use this script:

#!/bin/zsh

text="$(cat)"
if [ -z "$text" ]; then
  text="$*"
fi

if [ -z "$text" ]; then
  exit 0
fi

encoded="$(printf '%s' "$text" | /usr/bin/python3 -c 'import sys, urllib.parse; print(urllib.parse.quote(sys.stdin.read()))')"
open "prebabellens://translate?text=${encoded}"

5. Save (for example: Translate with zen-Babel).
6. Assign a keyboard shortcut in System Settings > Keyboard > Keyboard Shortcuts > Services.

Reliability and Fallback Behavior

The app prioritizes completion and visibility of failures:

• Per-segment fallback to source text when translation is unavailable/unsafe
• Retry guards for recoverable engine errors
• Explicit propagation of cancellation (no hidden fallback on user stop)
• Observable diagnostics in Developer Console

Project Structure

• Sources/App/: app entry points and lifecycle
• Sources/Features/Translation/: translation UI and state
• Sources/Domain/: core models and protocols
• Sources/Engines/Preprocess/: preprocessing engines
• Sources/Engines/Translation/: translation backends
• Sources/Services/: orchestration, policy, diagnostics
• Tests/: unit/integration tests

Build

swift build is for core/development verification (SwiftPM build), not a distributable .app bundle build.

swift build

Test

swift test

Localization

UI strings are managed in Localizable.strings under:

• Sources/Resources/en.lproj/Localizable.strings
• Sources/Resources/ja.lproj/Localizable.strings
• Sources/Resources/ko.lproj/Localizable.strings
• Sources/Resources/zh-Hans.lproj/Localizable.strings
• Sources/Resources/zh-Hant.lproj/Localizable.strings

How to add/update localized text:

1. Add a key in code via localized("your.key", defaultValue: "...") (or NSLocalizedString with the same key).
2. Add/update the same key in en.lproj/Localizable.strings first (source of truth).
3. Add/update the key in each supported locale file.
4. Keep key names stable; do not rename existing keys unless necessary.
5. Build and verify labels in app menus and translation screens.

Notes:

• defaultValue should be clear fallback English text.
• Prefer adding new keys instead of overloading old keys with different meaning.

Local Signing and Notarization

Official artifacts are built and signed locally on macOS, then notarized and stapled locally. Do not treat GitHub-hosted CI build artifacts as official distributables.

Preferred script:

scripts/build_notarized_release.sh

Notarization credentials:

• Recommended: NOTARY_PROFILE (Keychain profile from xcrun notarytool store-credentials)
• Fallback: APPLE_ID + app-specific password + APPLE_TEAM_ID

Typical flow:

1. Local release build
2. Developer ID codesign
3. Notarization submit/wait
4. Staple + validate

License

This project is licensed under the MIT License. See LICENSE.