Simple C++ Compiler

A basic compiler implementation in C++ that supports a subset of C-like syntax. Currently only implements lexical analysis, parsing, and semantic analysis phases.

Features

• Lexical Analysis (Tokenization)
• Abstract Syntax Tree (AST) Generation
• Semantic Analysis
  • Variable scope tracking
  • Variable initialization checking
  • Basic type checking

Supported Syntax

Currently supports:

int main() {
    int x = 42;
    if (x > 0) {
        return x * 2;
    }
    return 0;
}

Language Features

• Integer variables
• Basic arithmetic operations (+, -, *, /)
• Comparison operators (>, <, >=, <=, ==)
• If statements
• Return statements
• Block scoping

Prerequisites

• C++17 compatible compiler (Clang++ recommended)
• Make build system
• CMake (optional)

Project Structure

.
├── include/
│   ├── lexer.hpp
│   ├── parser.hpp
│   ├── semantic_analyzer.hpp
│   └── utils.hpp
├── src/
│   └── main.cpp
├── Makefile
├── .gitignore
└── README.md

Building from Source

1. Clone the repository:

git clone https://github.com/Sunsvea/coulstock-cpp-compiler.git
cd cpp-compiler

2. Create build directory:

mkdir build

3. Build using Make:

make

This will create the compiler executable in the build directory.

Usage

1. Basic usage:

./build/compiler

The compiler will process the default test program embedded in main.cpp.

2. To modify the input program, edit the input string in src/main.cpp:

std::string input = R"(
    // Your program here
)";

Example Output

The compiler produces detailed output showing each compilation phase:

Tokens:
Token: INT | Value: 'int' | Line: 2 | Column: 1
Token: IDENTIFIER | Value: 'main' | Line: 2 | Column: 5
...

Parsing AST:
Function: main
  Block:
    Variable Declaration: x
      Initializer:
        Number: 42
    If Statement:
      Condition:
        Binary Expression:
          Left:
            Identifier: x
          Operator: GREATER
          Right:
            Number: 0
...

Semantic analysis completed successfully!

Error Handling

The compiler provides detailed error messages for various types of errors:

1. Lexical errors (invalid characters, malformed tokens)
2. Syntax errors (invalid program structure)
3. Semantic errors:
   • Use of undeclared variables
   • Use of uninitialized variables
   • Variable redeclaration
   • Scope violations

Example error messages:

Semantic Error: Use of undeclared variable 'y'
Semantic Error: Use of uninitialized variable 'x'
Semantic Error: Variable 'x' is already declared in this scope

License

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

Acknowledgments

• Based on modern compiler implementation practices
• Inspired by the LLVM project structure