JavaScript Compiler Project

Introduction

Welcome to the JavaScript Compiler Project. The goal of this project is to develop a compiler capable of translating specific fragments of JavaScript code into a custom assembly language. This endeavor involves two critical stages:

1. Parsing: Ensuring the input JavaScript code adheres to the expected syntax.
2. Compilation: Transforming valid JavaScript code into executable assembly code compatible with a provided virtual machine.

This project allows us to explore the inner workings of parsers, lexers, and compilers while adhering to strict project specifications.

What is a Parser and Lexer?

• Lexer (Lexical Analyzer): The lexer processes raw input text and breaks it into manageable units called tokens, such as identifiers, keywords, and operators. It serves as the first step in transforming code into a structured format.
• Parser: The parser takes these tokens and organizes them according to grammatical rules, constructing a syntax tree that represents the structure of the code.

Parser Type Used

In this project, we implemented a LL(k) parser using JavaCC, which processes input from left to right and constructs a leftmost derivation of the input. LL parsers are well-suited for context-free grammars and allow us to easily handle JavaScript's hierarchical structure.

Fragments Overview

The compiler supports multiple JavaScript fragments, incrementally expanding its capabilities. The development covers fragments 0 through 8, starting with arithmetic expressions and progressing to advanced constructs like exceptions and classes. Each fragment builds upon the previous one, integrating features such as:

• Boolean operations
• Variables
• Loops
• Functions
• Dynamic types
• Object-oriented programming

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Required Software

To run this project, you'll need:

• Java (version 8 or higher)
• JavaCC (for parser and lexer generation)
• A Shell terminal with appropriate packages installed

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How to Compile the Project

1. Clone the repository:

   git clone <repository-url>
   cd <repository-folder>

2. Compile the parser:

   #modify you test.js file
   ./mi-makefile.sh

3. The generated code can be excecuted in the virtual machine :
   http://lipn.univ-paris13.fr/~breuvart/compilation/interpreteurJS/

Grammar

<program> ::= ϵ | <command> <program>

<command> ::= <expression> ;
          | import <IDENT> ;
          | ;
          | {<program>}
          | let <IDENT> ;
          | if ( <expression> ) <command> else <command>
          | while ( <expression> ) <command>
          | function <IDENT> (<decl_args>) { <program> }
          | return <expression> ;
          | try { <program> } catch ( <IDENT> ) { <program> }

<decl_args> ::= ϵ | <IDENT> | <IDENT> , <decl_args>

<expression> ::= <NUMBER> | <BOOLEAN> | <IDENT>
             | undefined
             | (<expression>)
             | <IDENT> = <expression>
             | <expression> + <expression>
             | <expression> - <expression>
             | <expression> * <expression>
             | <expression> / <expression>
             | <expression> == <expression>
             | <expression> > <expression>
             | <expression> >= <expression>
             | <expression> && <expression>
             | ! <expression>
             | - <expression>
             | <IDENT> ( <arguments> )
             | function (<decl_args>) { <program> }
             | (<decl_args>) => <expression>
             | {<object_content>} | Null
             | <expression> . <IDENT>

<arguments> ::= ϵ | <expression> | <expression> , <arguments>