How to build

• I built this project using Xcode Version 16.0 (16A242) and tested it on macOS 15.1 Beta (24B5035e).
• If you have any issues, feel free to contact me.

Features

• Game logic for arbitrary sizes and guess counts.
• Autocompletion for equation input. It suggests the part after "=" sign. Try it out, it is pretty cool little feature!
  • To accept the completion, press return key. To submit the guess, press it again.
• Navigation using keyboard arrows
  • Left/right to move cursor.
  • Up to substitute last guess, proved to be useful.
  • Down to clear current guess.
  • Navigation logic is similar to the original game, with some QoL tweaks.
• Keyboard input as well as on-screen keyboard.
  • Unfortunately, first responder is sometimes lost due to SwiftUI bug, you can re-enable keyboard input by clicking on the game field.
• Three difficulty levels.
  • Use gear button to change. Will only affect new practice games.
• Daily and Practice modes. Daily mode is guaranteed to be equal for all players.
  • Calendar button on toolbar loads daily mode.
  • Plus button loads practice mode (usable only on finished games).
• History persistence into sqlite database. Ability to load and view played games. Stats display.
• Ability to share game results using system share sheet.
• State restoration after application termination. It will restore your game, if you had any guesses in it.
• Slick UI, with some small animations here and there.
• Ability to create custom game from the equation in pasteboard. Use Command+N or click on menu item under File menu.

Implementation details

• Equations are parsed and validated using simple recursive descent parser.
• Generation of random equations works by constructing random left hand parts as strings and repeating this process until the correct sized option will be found.
• Persistence is implemented using GRDB, my favourite SQLite library out there. This is the single one external dependency out there.
  • Please don't ask me about CoreData/SwiftData. They are garbage =)
• UI is implemented in SwiftUI, using AppKit in tight places and to manage the application lifecycle. SwiftUI Previews are used here and there for quick iterations.
• The project is divided into host application xcodeproj and NerdleKit framework package.
• NerdleKit coverage with tests is about 95%. Tested code includes
  • Expression parsing/validating.
  • Game logic for coloring different symbols on field.
  • Game state logic and termination conditions.
  • Input logic and cursor management.
  • Persistence tests with in-memory SQLite DB.
• For host application, mainly MVVM-like solution is used. GameViewModel is pretty big, that is a good place for refactoring, probably. Some of its logic may be tested as well.