ErSantis / TopDownParser_LL1-React

LL(1) grammar analyzer and parser simulator built with React and TypeScript. Calculates First/Follow sets, builds M-table, and simulates parsing.

LL(1) Grammar Analyzer — Non-Recursive Descent Parser

A web-based tool built in React + TypeScript for analyzing context-free grammars and simulating LL(1) parsers. This tool helps users understand and visualize compiler construction techniques such as First/Follow sets, left recursion removal, and predictive parsing.

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📚 Features

• ✍️ Input grammar via web UI
• 🧮 Calculate First and Follow sets
• 🔁 Remove left recursion
• 🪄 Apply left factoring
• 📊 Generate LL(1) parsing table (M-table)
• ⚙️ Simulate non-recursive descent parsing
• 🌐 Interactive and responsive interface

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🚀 Getting Started

Prerequisites

• Node.js ≥ 16.x
• npm or yarn

Installation

git clone https://github.com/your-username/LL1-grammar-analyzer.git
cd LL1-grammar-analyzer
npm install

Run Locally

npm run dev

Open http://localhost:5173 in your browser.

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🧠 How It Works

1. Input Grammar: Define non-terminals, terminals, and production rules.
2. Preprocessing: Handles elimination of left recursion and left factoring.
3. First/Follow Sets: Uses algorithms to derive sets for each non-terminal.
4. M-Table Construction: Based on the First and Follow sets, builds parsing table.
5. Parser Simulation: Enter input string and see the parsing process in action.

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🛠 Technologies Used

Area	Tech Stack
Frontend	React, TypeScript
Tooling	Vite
State & Logic	Custom Context + Hooks
Styling	CSS Modules

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📦 Folder Structure

src/
├── components/       # UI components (input, results, simulation)
├── styles/           # CSS Modules for each component
├── utils/            # Grammar logic (first, follow, m-table, transformations)
├── types/            # TypeScript types
└── main.tsx          # App entry point

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🧪 Example Use Case

• Input Grammar:

  S -> A a | b
  A -> A c | d
  

• First & Follow sets are calculated.
• Left recursion removed from A -> A c | d.
• Predictive table created and parsing simulated.

---

🌐 Live Demo

Vercel

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📄 License

MIT License

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🙌 Authors

Developed as a compiler theory project by a team passionate about education and software engineering.

LL(1) Grammar Analyzer — Non-Recursive Descent Parser

A web-based tool built in React + TypeScript for analyzing context-free grammars and simulating LL(1) parsers. This tool helps users understand and visualize compiler construction techniques such as First/Follow sets, left recursion removal, and predictive parsing.

---

📚 Features

• ✍️ Input grammar via web UI
• 🧮 Calculate First and Follow sets
• 🔁 Remove left recursion
• 🪄 Apply left factoring
• 📊 Generate LL(1) parsing table (M-table)
• ⚙️ Simulate non-recursive descent parsing
• 🌐 Interactive and responsive interface

---

🚀 Getting Started

Prerequisites

• Node.js ≥ 16.x
• npm or yarn

Installation

git clone https://github.com/your-username/LL1-grammar-analyzer.git
cd LL1-grammar-analyzer
npm install

Run Locally

npm run dev

Open http://localhost:5173 in your browser.

---

🧠 How It Works

1. Input Grammar: Define non-terminals, terminals, and production rules.
2. Preprocessing: Handles elimination of left recursion and left factoring.
3. First/Follow Sets: Uses algorithms to derive sets for each non-terminal.
4. M-Table Construction: Based on the First and Follow sets, builds parsing table.
5. Parser Simulation: Enter input string and see the parsing process in action.

---

🛠 Technologies Used

Area	Tech Stack
Frontend	React, TypeScript
Tooling	Vite
State & Logic	Custom Context + Hooks
Styling	CSS Modules

---

📦 Folder Structure

src/
├── components/       # UI components (input, results, simulation)
├── styles/           # CSS Modules for each component
├── utils/            # Grammar logic (first, follow, m-table, transformations)
├── types/            # TypeScript types
└── main.tsx          # App entry point

---

🧪 Example Use Case

• Input Grammar:

  S -> A a | b
  A -> A c | d
  

• First & Follow sets are calculated.
• Left recursion removed from A -> A c | d.
• Predictive table created and parsing simulated.

---

🌐 Live Demo

Coming Soon (or host it on Vercel / Netlify for easy sharing)

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📄 License

MIT License

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🙌 Authors

Developed as a compiler theory project by me :)