🚀 Mini Expression Compiler with GTK GUI

A feature-rich arithmetic expression compiler with a GTK3 graphical interface, smart error detection, and assembly-like code generation.

📋 Features

• ✅ Lexical Analysis - Tokenizes arithmetic expressions
• ✅ Syntax Parsing - Validates grammar using Bison
• ✅ Error Detection - Smart error messages with suggestions
• ✅ Code Generation - Generates three-address assembly-like code
• ✅ GTK3 GUI - User-friendly graphical interface
• ✅ File Upload - Load .txt files directly
• ✅ Real-time Compilation - Instant feedback on code validity

🏗️ Project Structure

/MiniCompilerGUI
 ├── src/
 │    ├── lexer.l             # Flex: tokenization
 │    ├── parser.y            # Bison: grammar & syntax checking
 │    ├── codegen.c           # Assembly code generator
 │    ├── error_handler.c     # Error messages & suggestions
 │    ├── ui.c                # GTK GUI implementation
 │    └── main.c              # Entry point & integration
 │
 ├── include/
 │    ├── codegen.h
 │    ├── error_handler.h
 │    └── ui.h
 │
 ├── samples/                 # Test input files
 │    ├── test_valid.txt      # Valid expressions
 │    ├── test_error.txt      # Error examples
 │    └── test_complex.txt    # Complex expressions
 │
 ├── Makefile                 # Build automation
 └── README.md                # This file

🔧 Prerequisites

Required Tools

• GCC - C compiler
• Flex - Lexical analyzer generator
• Bison - Parser generator
• GTK3 - GUI library
• Make - Build tool

Installation

Arch Linux (RECOMMENDED - Auto Setup):

# One-command setup (installs deps + builds)
./setup-arch.sh

# Or manual steps:
sudo pacman -S --needed gtk3 flex bison base-devel
make

Ubuntu/Debian:

sudo apt-get update
sudo apt-get install libgtk-3-dev flex bison build-essential
make

Fedora/RHEL/CentOS:

sudo dnf install gtk3-devel flex bison gcc make
make

Quick Makefile Commands:

make install-deps-arch    # Arch Linux
make install-deps         # Ubuntu/Debian
make install-deps-fedora  # Fedora/RHEL

🚀 Building the Project

Quick Start

# Build the compiler
make

# Build and run
make run

# Clean build artifacts
make clean

# Rebuild from scratch
make rebuild

Manual Build

# Generate lexer
flex src/lexer.l

# Generate parser
bison -d src/parser.y

# Compile
gcc -Wall `pkg-config --cflags gtk+-3.0` -I./include \
    lex.yy.c parser.tab.c src/*.c \
    -o MiniCompilerGUI \
    `pkg-config --libs gtk+-3.0` -lfl

# Run
./MiniCompilerGUI

📖 Usage

GUI Interface

1. Launch the application:

   ./MiniCompilerGUI

2. Enter code or open a file:

   • Type expressions directly in the input area
   • Click "📁 Open File" to load a .txt file

3. Compile:

   • Click "⚙️ Compile" button
   • View results in the output area

4. Other buttons:

   • "🗑️ Clear" - Clear input and output
   • "❌ Exit" - Close the application

Supported Syntax

Valid Expressions:

x = 10 + 5;
y = x * 2;
z = (x + y) / 3;
result = x + y * z - 10;

Operators:

• + Addition
• - Subtraction
• * Multiplication
• / Division
• () Parentheses for grouping
• = Assignment
• ; Statement terminator

Comments:

// This is a comment
x = 5; // Inline comment

🧪 Testing

Run with Sample Files

Test valid expressions:

# In GUI: Open File → samples/test_valid.txt → Compile

Test error detection:

# In GUI: Open File → samples/test_error.txt → Compile

Test complex expressions:

# In GUI: Open File → samples/test_complex.txt → Compile

Sample Output

Valid Code:

✅ Compilation Successful!

; Generated Assembly-like Code
; Three-Address Code Format

MOV x, 15
MOV y, 30
ADD t0, x, y
MOV z, t0

Error Detection:

❌ Error at line 2: Invalid expression in assignment
💡 Suggestion: Check for missing operators or unmatched parentheses

❌ Error at line 4: Missing closing parenthesis ')'
💡 Suggestion: Add ')' to close the expression

📚 Grammar Rules

Tokens (Lexer)

NUMBER    : [0-9]+
ID        : [a-zA-Z_][a-zA-Z0-9_]*
ASSIGN    : =
SEMICOLON : ;
PLUS      : +
MINUS     : -
MUL       : *
DIV       : /
LPAREN    : (
RPAREN    : )

Grammar (Parser)

program    → statement*
statement  → ID = expression ;
expression → expression + term
           | expression - term
           | term
term       → term * factor
           | term / factor
           | factor
factor     → NUMBER
           | ID
           | ( expression )

👥 Team Roles

Member	Responsibility
Member 1	Lexer implementation (lexer.l)
Member 2	Parser implementation (parser.y)
Member 3	Code generator (codegen.c/h)
Member 4	Error handler (error_handler.c/h)
Member 5	GUI & Integration (ui.c, main.c)

🔍 Code Generation

The compiler generates three-address code in assembly-like format:

Instructions:

• ADD dest, src1, src2 - Addition
• SUB dest, src1, src2 - Subtraction
• MUL dest, src1, src2 - Multiplication
• DIV dest, src1, src2 - Division
• MOV dest, src - Assignment

Example:

Input:  result = (a + b) * c;

Output:
ADD t0, a, b
MUL t1, t0, c
MOV result, t1

🐛 Error Handling

The compiler provides intelligent error messages:

1. Missing operators:

   x = 10 +;
   → Error: Invalid expression in assignment
   → Suggestion: Check for missing operators
   

2. Unmatched parentheses:

   z = (10 + 5;
   → Error: Missing closing parenthesis ')'
   → Suggestion: Add ')' to close the expression
   

3. Invalid characters:

   result = x @ y;
   → Error: Unknown character or token
   → Suggestion: Remove invalid characters
   

📸 Screenshots

Place your GUI screenshots in the screenshots/ directory:

• screenshots/gui_main.png - Main interface
• screenshots/valid_compile.png - Successful compilation
• screenshots/error_detection.png - Error messages

🎓 Educational Value

This project demonstrates:

• Compiler Design - Lexical analysis, parsing, code generation
• Error Recovery - Graceful error handling
• GUI Development - GTK3 programming
• Build Systems - Makefile automation
• Team Collaboration - Modular architecture

📝 Makefile Commands

make                      # Build the compiler
make run                  # Build and run
make clean                # Remove build artifacts
make rebuild              # Clean and rebuild
make install-deps         # Install deps (Ubuntu/Debian)
make install-deps-fedora  # Install deps (Fedora)
make install-deps-arch    # Install deps (Arch)
make test                 # Run with sample input
make help                 # Show help message

🔮 Future Enhancements

• Add if and while statements
• Support for functions
• Floating-point arithmetic
• Variable type checking
• Optimization passes
• Syntax highlighting in GUI
• Save generated code to file
• Debug mode with step-by-step execution

📄 License

This is an educational project for learning compiler construction and GUI development.

👨‍💻 Contributors

Built by a team of 5 members as part of a compiler design course.

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Happy Compiling! 🎉