🧠 Dart Turing Machine Emulator

A minimalistic Turing Machine emulator implemented entirely in Dart, featuring an extendable opcode system, infinite tape simulation, and several sample "programs" (tapes) that demonstrate printing, arithmetic, conditional branching, user input, and even a self-replicating quine.

---

🚀 Features

• 🧾 Finite State Control — Centralized control flow handling all instructions.
• ♾️ Infinite Tape — Implemented as a sparse map for unbounded memory access.
• 🪄 Tape Head — Supports moving, reading, and writing across infinite cells.
• 🧩 Opcodes System — Extensible instruction set (print, increment, input, copy, etc).
• 🌀 Non-deterministic Option — Optional chaos mode for random opcode substitution.
• 🧍 Delegate Interface — Clean separation between logic and memory management.
• 💡 Example Programs:
  • Hello World
  • Count to Sixteen
  • Count Down to Zero
  • Number Guessing Game
  • Quine (self-replicating program)

---

🧩 Opcodes

Opcode	Description
stop	Halts the machine
print	Prints the next symbol
increment next	Increments the numeric value of the next symbol
decrement next	Decrements the numeric value of the next symbol
if previous not equal	Conditional execution block
move to index	Moves the tape head to a specific index
copy from index to index	Copies a value from one cell to another
input to next	Reads user input and writes it to the next cell
generate random number from zero to next and write after	Writes a random integer to tape

---

🧮 Example Tapes

The main() function defines and runs several tapes sequentially:

🖨️ 1. Hello World

Prints “hello world” and stops.

helloWorldTape.write(symbol: "print", at: 0);
helloWorldTape.write(symbol: "hello world", at: 1);
helloWorldTape.write(symbol: "stop", at: 2);

🔢 2. Count to Sixteen

Increments numbers from 0 to 16 and prints each value.

🔻 3. Count Down to Zero

Decrements numbers from 16 to 0 and prints each value.

🎲 4. Guess the Number

Asks user to guess a random number between 0 and 4.

🪞 5. Quine

A self-replicating Turing program that outputs its own tape source.

---

⚙️ Running the Emulator

🧱 Requirements

• Dart SDK ≥ 3.0
  Install from dart.dev

▶️ Run

dart run main.dart

You’ll see several demo tapes execute in sequence, printing results to the console.

---

🧠 Architecture Overview

FiniteStateControl
 ├─ handles opcodes and logic
 │
 ├── delegate → TuringMachine (implements FiniteStateControlDelegate)
 │     ├── TapeHead (controls current position)
 │     └── InfiniteTape (Map-based memory)

---

🔍 Debug Options

Enable various debug flags at the top of the file:

const DEBUG_PRINT_ENABLED = true;
const DEBUG_MODE_ENABLED = true;
const DEBUG_PRINT_TAPE = true;

• DEBUG_PRINT_ENABLED → Log every symbol and opcode
• DEBUG_MODE_ENABLED → Step-by-step execution (press Enter to continue)
• DEBUG_PRINT_TAPE → Print tape contents after each operation

---

🧪 Extending the Machine

To add a new opcode:

1. Define it as a new constant:

   const OPCODE_NEW_OPERATION = "new operation";

2. Add it to the opcodes list.
3. Implement its behavior in FiniteStateControl.handle().

---

🧰 Example Output

---Next Tape---
hello world

---Next Tape---
16
15
...
0
Finished!

---Next Tape---
Guess number (0-4):
> 2
Wrong!
Number: 3

---Next Tape---
????????????????
(copying and printing itself...)

---

📜 License

MIT License
Copyright (c) 2025

Free to use, modify, and experiment.

---

🧑‍💻 Author

Developed by Ilia Prokhorov
A playful exploration of computation theory, recursion, and chaos—implemented in Dart.