Lexical Analyzer for Custom Language

Welcome to the Lexical Analyzer for a custom programming language. This project builds a lexical analyzer that converts source code into tokens using finite automata (NFA & DFA). It supports various data types, operators, keywords, and comments with well-defined regular expressions.

🚀 Features

• Custom Tokenization: Converts source code into categorized tokens.
• Finite Automata Implementation: Uses NFA (Thompson's construction) and DFA for efficient lexical analysis.
• Symbol Table Management: Stores identifiers with scopes.
• Comment Handling: Ignores single-line and multi-line comments.
• Operator Recognition: Supports arithmetic and exponentiation.

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📝 Language Rules

Reserved Keywords

Type	Keyword
Integer	int
Decimal	dec
Boolean	bln
Character	char
Global	mrWorld
Local	mrArea

Data Types

• Integer (int)
• Decimal (dec)
• Boolean (bln)
• Character (char)

Constraints

• Only lowercase alphabets allowed for identifiers [a-z].

Comments

Type	Syntax
Single-Line	%% This is a comment
Multi-Line	`%* This is a
multi-line comment *%`

Operators

Operator	Description
+	Addition
-	Subtraction
*	Multiplication
/	Division
%	Modulus
^	Exponentiation

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🔍 Regular Expressions

Token Patterns

Token Type	Regex
Reserved Keywords	`(int
Identifiers	[a-z][a-z0-9_]*
Integer	\d+
Decimal	\d+\.\d{1,5}
Boolean	`(true
Character	'[a-z]'
Single-line Comment	%%.*
Multi-line Comment	`%*(*(?!%)
Operators	[+\-*/%^]
Whitespace	[ \t\n]+

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🛠 How It Works

1. Define Tokens using Regular Expressions.
2. Convert Regular Expressions to NFA using Thompson’s construction.
3. Transform NFA to DFA for faster token recognition.
4. Scan Input Source Code, match tokens, and generate a symbol table.
5. Skip Comments and Report Errors for invalid syntax.

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📌 Example Code & Token Output

Sample Input (test.sui)

int x = 10
dec y = 3.14
mrWorld z = true
%* This is a multi-line comment *%
x + y ^ 2

Tokenized Output

Token [type=KEYWORD, value=int, line=1]
Token [type=IDENTIFIER, value=x, line=1]
Token [type=ASSIGNMENT, value==, line=1]
Token [type=INTEGER, value=10, line=1]
...
Token [type=OPERATOR, value=^, line=5]

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🛠 Installation & Usage

1️⃣ Clone the Repository

git clone https://github.com/MuhammadRafay1/LexAnlyzer.git
cd LexAnlyzer

2️⃣ Compile & Run

javac src/*.java -d bin/
java -cp bin/ Main

3️⃣ Modify test.sui and Re-run

Update your test file and analyze different inputs.