🐍 SerpentJS

Python → JavaScript Transpiler

Write Python. Run JavaScript.

SerpentJS is a modern Python → JavaScript transpiler built from scratch using compiler construction principles.
It converts a well-defined subset of Python into clean, readable, and executable JavaScript while preserving program structure and logic.

This project follows a full compiler pipeline — lexical analysis, parsing, semantic analysis, optimization, and code generation — without using parser generators or external compiler frameworks.

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📚 Table of Contents

• Overview
• Project Goals
• Supported Features
• Key Algorithms & Techniques
• AST Visualization
• Technologies Used
• Installation

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🧠 Overview

SerpentJS bridges Python’s expressive syntax with JavaScript’s runtime ecosystem.
It allows developers and students to reuse Python logic in JavaScript environments and understand how real-world compilers and transpilers work internally.

The transpiler is modular, extensible, and educational, making it suitable for:

• Compiler construction learning
• Language translation experiments
• Cross-platform logic reuse

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🎯 Project Goals

• Build a Python-to-JavaScript transpiler from scratch
• Support core Python language constructs
• Preserve logic and execution behavior
• Provide clear grammar mapping
• Implement robust error handling and reporting
• Generate clean and optimized JavaScript code

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✅ Supported Features

Language Constructs

• Functions (definition & calls)
• Control Flow
  • if / elif / else
  • while
  • for ... in ...
• Assignments (single variable)
• Expressions
  • Arithmetic
  • Comparison
  • Logical
  • Unary
  • Grouping
• Literals
  • Integers
  • Floats
  • Strings
  • Booleans
  • None

Keywords

def, return, if, elif, else, while, for, in, True, False, None

Operators

+ - * / % ** == != < > <= >= and or not

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Each phase is implemented independently to ensure clarity, maintainability, and extensibility.

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⚙ Key Algorithms & Techniques

🔹 Lexical Analysis

• Manual tokenization using regular expressions
• Indentation tracking via INDENT / DEDENT tokens
• Line and column–based error reporting

🔹 Syntax Analysis

• Recursive Descent Parsing
• Operator precedence handling
• AST construction using structured node classes

🔹 Semantic Analysis

• Symbol table with nested scopes
• Type inference and validation
• Detection of undeclared identifiers
• Protection of built-in names

🔹 Optimization

• Constant folding
• Dead code elimination
• Expression simplification
• Scope-aware transformations

🔹 Code Generation

• Post-order AST traversal
• Python → JavaScript syntax mapping
• Automatic variable declaration tracking
• ES6+ compatible output

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🌳 AST Visualization

SerpentJS supports AST visualization for debugging and learning:

• Console-based AST printing
• Graphviz integration for graphical AST rendering

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🧰 Technologies Used

• Python 3.x – Core implementation language
• JavaScript (ES6+) – Target output language
• Graphviz – AST visualization
• Git & GitHub – Version control
• VS Code – Development environment
• Jupyter Notebook – Testing & demonstrations

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📦 Installation

git clone https://github.com/FatimaM05/SerpentJS.git