NerdCalci

Fully offline Android calculator app for power users with variable support, syntax highlighting, file-based sessions, and more. A free Android alternative to proprietary text-based calculators like Numi, Calca, and Soulver.

Features

Smart calculations

[!NOTE] All supported operators, functions, and advanced syntax is extensively explained and documented in the reference guide.

• Variable support

  a = 100
  b = 200
  total = a + b  # 300
  

• Composite operations

  score = 10
  score += 5     # 15
  score++        # 16
  score /= 4     # 4
  

• Percentage calculations

  20% of 50000    # 10000
  15% off 1000    # 850
  50000 + 10%     # 55000
  50000 - 5%      # 47500
  

• Dynamic variables

  groceries = 45.50
  utilities = 120
  rent = 950
  total           # 1115.50
  
  feb = 200
  mar = 300
  avg             # 250
  

• Unit conversions & arithmetic

  10km + 500m    # 10500 m
  5 kg to g      # 5000 g
  100 °C as °F    # 212 °F
  

• Numeral systems

  5 million       # 5000000
  1.5 crore       # 15000000
  

• Comments

  price = 1000  # base price
  tax = 18% of price  # 180
  

• User-defined functions

  sq(x) = x ^ 2
  sq(5)          # 25
  
  # Support for multi-statement bodies
  salary(hours) = base = hours * 50; bonus = base * 0.1; base + bonus
  salary(160)    # 8800
  

• Cross-file references

  f = file("Summary")
  total_cost = f.total * 1.1
  
  # Or invoke functions directly
  file("Calculations").taxFunc(1000)
  

• Mathematical functions

  sqrt(16)           # 4
  sin(PI/2)          # 1
  sin(45)            # 0.85 (radians by default)
  sin(45°)           # 0.7071 (supports degrees)
  

Editor features

• Syntax highlighting: Color-coded variables, numbers, operators, and comments
• Smart error diagnostics: See human-friendly explanation of math or syntax errors
• Auto-completion: Smart variable suggestions as you type
• Line numbers: Easy reference and navigation

File management

• Multiple files: Create and manage separate calculation files
• Auto-save: Changes are saved automatically
• Pin files: Keep important files at the top (max 10 pinned files)
• Search: Search files easily
• Duplicate files: Create a copy of a file with a new name
• Backups: Automatically or manually backup your files to app storage or a custom folder
• Restore from backups: Restore your files safely with support for conflict resolution (Keep local, replace, or keep both)
• Copy with results: Copy file content with calculated results to clipboard
• Export: Share your calculations as a PNG image or a multi-page PDF

And more...

• Offline: Works without internet
• Undo/Redo: Up to 30 steps per file
• Dark/light theme: System, dark, or light mode
• Real-time results: See calculations update as you type

Built with

• Kotlin - Primary programming language
• Jetpack Compose - Modern UI toolkit
• Room Database - Local data persistence
• Material Design 3 - UI components and theming
• Fira Code - Monospace font with ligatures

Inspiration

A heartfelt thank you to the brilliant creators behind these incredible text-based calculators that inspired the creation of NerdCalci:

• Numi
• Calca
• Soulver

Development

Running tests

Run all unit tests:

./gradlew :app:testDebugUnitTest

Run specific test class:

./gradlew :app:testDebugUnitTest --tests "com.vishaltelangre.nerdcalci.core.MathEngineTest"

After running tests, view the HTML report:

open app/build/reports/tests/testDebugUnitTest/index.html

To run instrumentation tests:

./gradlew :app:connectedDebugAndroidTest

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the project
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

License

This project is licensed under the GNU General Public License v3.0 - see the LICENSE file for details.