Compiler Project

Overview

This project implements a compiler that processes input source code using lexical and syntactic analysis techniques. It builds a Deterministic Finite Automaton (DFA) and Non-deterministic Finite Automaton (NFA) for lexeme identification and performs parsing using an LL(1) grammar approach.

Project Structure

./
    │-- lexeme.txt
    │-- codeinput.txt
    │-- grammar.conf
    │-- output.txt
src/compiler_project
    │-- DFA.java
    │-- DFA_State.java
    │-- LL1_Grammer.java
    │-- MakeNFA.java
    │-- NFA.java
    │-- NFA_State.java
    │-- compiler_project.java
    │-- make_Analysis_table.java

Key Components

1. Lexical Analysis (NFA and DFA)

   • MakeNFA.java: Converts regular expressions into NFAs.
   • NFA.java & NFA_State.java: Handles NFA representation and state transitions.
   • DFA.java & DFA_State.java: Converts NFAs to DFAs for efficient lexeme recognition.

2. Syntactic Analysis (LL(1) Grammar Parsing)

   • LL1_Grammer.java: Implements LL(1) parsing techniques.
   • make_Analysis_table.java: Constructs parsing tables based on grammar rules.

3. Main Compiler Logic

   • compiler_project.java

     : The main entry point for the compiler, responsible for:

     • Reading input files (lexeme.txt, codeinput.txt, grammar.conf)
     • Constructing NFAs and DFAs for tokenization
     • Generating parse tables and performing syntax analysis

Features

• Lexical Analysis
  • Reads lexeme definitions from lexeme.txt
  • Converts regular expressions to NFA and then DFA
  • Tokenizes input code based on defined lexemes
• Syntactic Analysis
  • Reads grammar rules from grammar.conf
  • Constructs an LL(1) parsing table
  • Parses the tokenized input for syntactic correctness
• File Handling
  • Reads input source code from codeinput.txt
  • Writes tokenized output to output.txt

Installation and Usage

Prerequisites

• Java Development Kit (JDK) 8 or higher.
• Apache Commons Lang library (used in LL1_Grammer.java).

How to use

First you need to compile the project and the run the compiler:

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

File Formats

Lexeme File (lexeme.txt) Example:

digit := [0-9]
left_brace := \[
l := [a-z]|[A-Z]
char_literal := '
string_literal := "
operation := \*|-|\+\+|--|/
number_real := \digit+\.\digit+
number_integer := \digit+
comment := @@#(\number_integer)-(\string_literal).*(\string_literal)
key_word := while|int|char|for|if
id := \l(\l|_|\digit)+

Source Code File (codeinput.txt) Example:

int x = 10;
if (x > 0) {
    print(x);
}

Grammar File (grammar.conf) Example:

<Prog> := { <Stmts> }
<Stmts> := <Stmt> <Stmts>
<Stmts> :=  
<Stmt> := id = <Expr> ;
<Stmt> := key_word ( <Expr> ) <Stmt>
<Stmt> := <Expr> = number_real  ;
<Expr> := number_integer <Etail>
<Expr> := id <Etail>
<Etail> := + <Expr> 
<Etail> := <Expr>
<Etail> :=  

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License

This project is licensed under the MIT License. see the LICENSE file for details.

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Enjoy and Let me know if you have any question.