---
license: mit
title: PDA_SIMULATOR
sdk: gradio
emoji: 💻
colorFrom: yellow
colorTo: indigo
pinned: false
---
# PDA Simulator – Theory of Computation Visual Tool

A presentation-style, interactive web application for simulating **Pushdown Automata (PDA)** — built with Flask, HTML, CSS, and JavaScript.

---

## 🚀 How to Run

### 1. Clone / Download the project
```
pda_simulator/
├── app.py
├── requirements.txt
├── static/
│   ├── style.css
│   └── script.js
└── templates/
    └── index.html
```

### 2. Create a virtual environment (recommended)
```bash
cd pda_simulator
python -m venv venv

# Windows
venv\Scripts\activate

# macOS / Linux
source venv/bin/activate
```

### 3. Install dependencies
```bash
pip install -r requirements.txt
```

### 4. Run the Flask app
```bash
python app.py
```

### 5. Open in browser
```
http://127.0.0.1:5000
```

---

## 🎯 Features
- **Three sample PDAs**: aⁿbⁿ, Balanced Parentheses, wcwᴿ
- **Step-by-step simulation** with Prev / Next / Auto-Play / Pause
- **SVG state diagram** with active state and transition highlighting
- **Stack visualizer** showing push/pop at each step
- **Input tape** with position pointer
- **Acceptance** by Final State or Empty Stack
- **Toast error messages** for invalid PDA definitions
- Modern dark sci-fi UI with glassmorphism cards

---

## 📖 Transition Format
```
current_state, input_symbol, stack_top -> next_state, push_value
```
- Use `ε` (or `eps`) for epsilon transitions
- Example:
  ```
  q0, a, Z -> q0, AZ
  q0, b, A -> q1, ε
  q1, ε, Z -> q2, Z
  ```

---

## 🛠 Tech Stack
| Layer    | Technology |
|----------|------------|
| Backend  | Python 3 + Flask |
| Frontend | HTML5 + CSS3 + Vanilla JS |
| Diagram  | SVG (drawn with JavaScript) |
| Fonts    | Google Fonts (Orbitron, Space Mono, Inter) |