XLang Project Rules

# XLang Project Rules

## Project Overview
XLang is a programming language implementation with a Python-based compiler and interpreter. The project uses Python 3.10+ and follows a modular architecture with separate components for parsing, validation, and interpretation.

## Project Structure
- `xlang/` - Main source code directory
  - `xl_ast.py` - Abstract Syntax Tree definitions
  - `xl_builtins.py` - Built-in functions and methods
  - `grammar.lark` - Grammar definitions
  - `interpreter.py` - Interpreter implementation
  - `parser.py` - Parser implementation
  - `validation_pass.py` - Validation pass
- `tests/` - Test files
  - `lit/` - LLVM-style lit tests
  - `unit/` - Unit tests

## Running Tests
There are two ways to run tests:

1. Direct Python execution:
```bash
python main.py --split-input-file tests/lit/your_test.xl
```

2. Using LLVM's lit testing tool:
```bash
# a single test file:
lit -v tests/lit/your_test.xl

# all test files:
lit -v tests/lit/
```