Stack Effect: The Game

Stack Effect: The Game is a lighthearted game designed to enhance your understanding of Forth words and stack operations.

About the Game

You'll encounter Forth-inspired stack operations and literals. Your goal is to guess the final state of the stack after a series of operations are applied. The game is simple to play and challenges your memory and intuition about stack-based programming.

Key Features:

• Random Forth-like operations (e.g., swap, dup, drop, etc.) manipulate the stack.
• 6 operations per round
• Visual representation of the top of the stack to track progress.

How to Play

1. Start the Game: Click the Start Game button to begin. A random stack operation or literal is applied every 2 seconds.
2. Track the Stack: Watch the top of the stack and think about how each operation affects it.
3. Submit Your Guess: After 6 turns, the game will stop, and you'll be prompted to guess the final state of the stack from top to bottom using emojis.
   • Example: If you think the final stack has 🍎 on top, followed by 🧸, type 🍎🧸 into the guess box.
4. Check Your Answer: Submit your guess and find out if you're right!

Stack Words and Operations

This game simulates a subset of Forth operations, including:

• Emoji Keypad: Quickly add literals to your guess by clicking the corresponding emoji.
• Delete Button: Remove the last emoji from your guess.
• Turn Counter: See how many turns have passed and how many remain.
• Reset Button: Restart the game at any time.
• Literals: 💎, 🌟, 🍎, etc. Push these onto the stack.
• Stack Manipulation:
  • rot: Rotate the top three items.
  • -rot: Reverse rotate the top three items.
  • nip: Remove the second item.
  • tuck: Copy the top item below the second item.
  • drop: Remove the top item.
  • 2drop: Remove the top two items.
  • dup: Duplicate the top item.
  • 2dup: Duplicate the top two items as a pair.
  • over: Copy the second item onto the top.
  • 2over: Copy the second pair onto the top.
  • 2swap: Swap the top two pairs.
  • swap: Exchange the top two items.

Did I miss one? Please raise an issue and I will add more words to the dictionary.

Each operation respects stack effect rules, ensuring consistency and predictability for those well-versed in Forth.

Behind the Scenes

The stack is implemented as a simple JavaScript array, and each operation modifies it in place, simulating Forth's stack behavior. Legal moves are determined dynamically based on stack depth and operation constraints.

Try It

I host a demo on my website.

Enjoy the game, and may your stack always be in perfect order!