🐱 MeowScript

A fun, cat-themed programming language with a live web playground. Write code using meow(), purr(), catnap(), and more!

Try it live →

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✨ Features

• 📢 Print — meow("Hello!") to display output
• 📦 Variables — x = 42 with full arithmetic support
• 🔀 Conditionals — if (x > 10) { ... }
• 🔄 Loops — while (x < 50) { ... }
• 😴 Delays — catnap(2) pauses execution
• 😸 Purring — purr() because every cat should purr
• 🛡️ Error handling — try { ... } scratch { ... }
• 💬 Comments — ~ purr purr this is a comment

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🚀 Quick Start

Try it online

Head to the live playground and start coding — no setup needed.

Run locally

# Clone the repo
git clone https://github.com/harshitt13/meowscript.git
cd meowscript

# Start the frontend
cd Frontend
npm install
npm run dev

# In another terminal — start the backend
cd Backend
npm install
node server.js

Frontend runs at http://localhost:5173, backend at http://localhost:3001.

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📖 Language Reference

Comments

~ purr purr this is a comment

Variables & Math

x = 10
y = 25
sum = x + y
meow("Total: " + sum)

Conditionals

if (x > 10) {
  meow("Big number!")
}

Loops

i = 0
while (i < 5) {
  meow("Meow #" + i)
  i = i + 1
}

Delays

meow("Getting sleepy...")
catnap(2)
meow("Awake!")

Error Handling

try {
  meow(oops)
} scratch {
  meow("Caught an error! 😼")
}

Full Example

~ purr purr Welcome to MeowScript!
x = 5
y = 10
z = x + y
meow("The sum is: " + z)

if (z > 10) {
  meow("😺 " + z + " is greater than 10!")
}

purr()

while (z < 20) {
  z = z + 2
  meow("z is now: " + z)
}

Output:

The sum is: 15
😺 15 is greater than 10!
😸 Purring...
z is now: 17
z is now: 19
z is now: 21

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🏗️ Project Structure

meowscript/
├── Backend/
│   ├── interpreter.js    # MeowScript interpreter (safe expression parser)
│   ├── server.js         # Express API server
│   ├── vercel.json       # Vercel deployment config
│   └── package.json
├── Frontend/
│   ├── src/
│   │   ├── App.jsx              # Main playground UI
│   │   ├── components/
│   │   │   └── Documentation.jsx  # Language reference cards
│   │   ├── styles.css           # App styles
│   │   ├── index.css            # Global styles & design tokens
│   │   └── main.jsx             # Entry point
│   ├── public/                  # Static assets
│   ├── index.html
│   └── package.json
└── README.md

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🛡️ Security

The interpreter uses a custom recursive descent parser for evaluating expressions — no eval() or Function() calls. User-submitted code runs in a sandboxed context with:

• Iteration limit — max 10,000 iterations per execution
• Execution timeout — 5 second hard limit
• Input validation — max 5,000 characters
• Rate limiting — 15 requests per minute per IP

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🚢 Deployment

Both frontend and backend are deployed on Vercel:

• Frontend — auto-deploys from Frontend/ directory
• Backend — auto-deploys from Backend/ directory as a serverless function

To deploy your own:

1. Fork this repo
2. Import each directory as a separate Vercel project
3. Set the backend URL in the frontend via the VITE_API_URL environment variable

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📜 License

MIT

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🤝 Contributing

PRs and issues are welcome! Whether it's a bug fix, new language feature, or UI improvement — feel free to contribute. 🐾

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If you like MeowScript, give it a ⭐ on GitHub!