🎯 MiniJavaCompiler-JS-DoWhile

A Java mini-compiler for JavaScript do...while loops, featuring lexical and syntax analysis using automata-based methods.

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📚 Project Overview

This project was developed for the Compilation module at Abderrahmane Mira University of Béjaia, as part of the final year Bachelor’s in Computer Science.

It demonstrates the front-end stages of a compiler:

• Lexical Analysis (Lexer)
• Syntax Analysis (Parser)

Specifically targets JavaScript do...while loops.

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⚡ Features

📝 Lexical Analysis (Lexer)

• Character-by-character scanning using a finite automaton
• Breaks code into lexemes and classifies tokens:
  • keyword, identifier, number, string, operator, delimiter
• Recognizes major JavaScript keywords: do, while, if, else, for, etc.
• Supports custom keywords: Rezouali, Imane
• Ignores comments and whitespace
• Detects and reports lexical errors with line numbers

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📐 Syntax Analysis (Parser)

Validates do...while loops:

do {
    <statements>
} while (<condition>);

• Checks proper use of braces {}, parentheses (), and semicolons ;
• Validates declarations, assignments, expressions, and operators
• Detects and reports syntax errors with line numbers
• Implemented using a recursive descent parser with finite automata and regular expressions

📖 Grammar Used

Simplified grammar for supported JavaScript constructs:

Program       -> StatementList EOF
StatementList -> Statement*
Statement     -> DoWhile | Declaration | Assignment | OtherStatement
DoWhile       -> 'do' Block 'while' '(' Expression ')' ';'
Block         -> '{' StatementList '}'
Declaration   -> ('var' | 'let' | 'const') Identifier ('=' Expression)? ';'
Assignment    -> Identifier '=' Expression ';'
Expression    -> Value ((Operator) Value)*
Value         -> Identifier | Number | String
Operator      -> ArithmeticOperator | ComparisonOperator

Arithmetic operators: +, -, *, /, %

Comparison operators: ==, !=, <, >, <=, >=

Testing the MiniJSIDE Compiler

Anyone wanting to test this from another machine should follow these steps:

1. Download the project repository to your computer or clone the repo.

2. Ensure Java is installed (Java JDK 8 or higher).

3. Run the executable:

• Option 1: Run via terminal (if you have Java 23 or higher):

java -jar B3_Rezouali_Imane.jar

• Option 2: Building a New JAR (Java 8–22)

  1. Open a terminal in the project directory.
  2. Delete any previous out directory (safe):

 rm -rf out

3. Create the output directory:

 mkdir -p out

4. Delete any previous B3_Rezouali_Imane.jar file (safe):

 rm -f B3_Rezouali_Imane.jar

5. Compile the source files. The repository places sources under src/ — compile all .java files and place class files into out:

 javac -d out src/*.java

6. Create the JAR file.

 jar cfe B3_Rezouali_Imane.jar Main -C out . && java -jar B3_Rezouali_Imane.jar

this project has a Main class in the default package, so use Main:

 jar cfe B3_Rezouali_Imane.jar Main -C out .

7. Run the JAR file:

 java -jar B3_Rezouali_Imane.jar

4. Using the IDE:

• Write, compile, and test JavaScript do...while loops.
• Click Compile to run lexical and syntax analysis.
• Click Show Tokens to display the tokens generated by the lexer.