Xel (/z·eh·l/)

Xel is a runtime environment for VirtLang, a dynamic, modern scripting language designed for simplicity, power, and extensibility. Xel provides the tools to write, execute, and manage VirtLang code, complete with a REPL, a standard library, and a module system.

Features

Language (VirtLang via Xel):

• Dynamic Typing: Flexible type system.
• Modern Syntax: Familiar C-like syntax with support for:
  • Variables (let) and Constants (const).
  • Functions (named, anonymous, closures).
  • Classes with public/private members and constructors.
• Rich Data Types: Includes Number, String, Boolean, Nil, Object, and Array.
• Control Flow: if/else if/else, while loops, break, continue.
• Error Handling: try/catch blocks.
• Module System: Simple import and exports for code organization.

Runtime (Xel):

• Script Execution: Run .xel script files directly from the command line.
• Interactive REPL: Experiment with VirtLang code in real-time.
• Standard Library: Built-in modules for math (xel:math), strings (xel:strings), and arrays (xel:array).
• CLI Tools: Intuitive command-line interface for running scripts and managing projects.
• Informative Error Reporting: Errors include line and column numbers for easier debugging.
• Environment Variables: Access script path (__filename__, __dirname__) and command-line arguments (proc.args).
• Automatic Version Checking: Get notified of new Xel releases.
• Cross-Platform: Available for macOS, Linux, and Windows.
• Lightweight: Minimal dependencies and fast startup time.

Installation

Quick Install (Linux, macOS, Windows with WSL)

You can install Xel with a single command:

curl -fsSL https://raw.githubusercontent.com/dev-kas/xel/master/scripts/install.sh | sh

This will automatically detect your operating system and architecture, download the appropriate binary, and install it to your system.

Update Xel

To update to the latest version:

curl -fsSL https://raw.githubusercontent.com/dev-kas/xel/master/scripts/update.sh | sh

Uninstall Xel

To remove Xel from your system:

curl -fsSL https://raw.githubusercontent.com/dev-kas/xel/master/scripts/uninstall.sh | sh

To uninstall without confirmation (useful for automated scripts):

curl -fsSL https://raw.githubusercontent.com/dev-kas/xel/master/scripts/uninstall.sh | sh -s -- -y

Manual Installation

1. Download the appropriate binary for your platform from the releases page.
2. Rename it to xel (or xel.exe on Windows).
3. Make it executable (on Unix-like systems): chmod +x xel.
4. Move it to a directory in your PATH (e.g., /usr/local/bin on Linux/macOS).

From Source

# Clone the repository
git clone https://github.com/dev-kas/xel.git
cd xel

# Build for your platform
make build

# Or build for a specific platform
make build-mac    # macOS (arm64)
make build-linux  # Linux (amd64)
make build-windows # Windows (amd64)

The compiled binaries will be available in the bin directory.

Usage

Basic Commands

# Check version
xel --version

# Show help
xel --help

Running Xel Scripts

Create a file with a .xel extension (e.g., myscript.xel).

# Basic usage
xel run myscript.xel

# With command-line arguments
xel run myscript.xel arg1 "another argument"

Arguments are accessible within the script via the proc.args array.

Interactive REPL (Read-Eval-Print Loop)

Run xel without any arguments to start the REPL:

xel

Welcome to Xel vX.Y.Z REPL (VirtLang vA.B.C)!
Type '!exit' to exit the REPL.
> let message = "Hello from REPL!"
< "Hello from REPL!"
> print(message)
Hello from REPL!
< nil
> 10 + 20
< 30

Example Xel Script

Create a file named example.xel:

// example.xel

// Import the strings module from the standard library
const strings = import("xel:strings")

// Define a function
fn greet(name) {
  return "Hello, " + name + "!"
}

let personName = "Xel User"
let greeting = greet(personName)

print(strings.upper(greeting))

if (len(proc.args) > 0) {
  print("You passed these arguments:")
  array.forEach(proc.args, fn(arg, index) {
    print(strings.format("Arg %v: %v", index + 1, arg))
  })
} else {
  print("Try running with arguments: xel run example.xel test1 test2")
}

Run it with:

xel run example.xel "first arg" 42

Expected Output:

HELLO, XEL USER!
You passed these arguments:
Arg 1: first arg
Arg 2: 42

Documentation

For detailed documentation on the Xel runtime and the VirtLang language features, syntax, and standard library, please refer to: DOCS.md

Standard Library Highlights

Xel comes with a useful set of built-in native modules:

• xel:math: For mathematical operations like sqrt, random, sin, cos, PI, E, aggregation functions (sum, mean, median), and more.
• xel:strings: For string manipulation like trim, split, upper, lower, includes, format, slice, and more.
• xel:array: For array operations like map, filter, reduce, push, pop, sort, slice, and more.

See DOCS.md for full details on available functions.

Development

Running Tests

Ensure you have Go installed. Then, from the project root:

make test

Contributing

Contributions are welcome and highly appreciated! Whether it's bug fixes, feature enhancements, documentation improvements, or new standard library modules, please feel free to submit a Pull Request.

Please see our CONTRIBUTING.md for detailed guidelines on how to contribute.

Release Process

Xel uses GitHub Actions for continuous integration and automated releases:

1. Every push to the master branch and pull requests are automatically built and tested.
2. To create a new release:
   • Create and push a new tag with the version number (e.g., git tag v1.0.0 && git push origin v1.0.0).
   • GitHub Actions will automatically build the binaries for all supported platforms.
   • A new GitHub Release will be drafted with the binaries attached.
   • Once the release is published, the installation scripts will automatically use the latest release.

Acknowledgements

Xel builds upon the VirtLang-Go v2 engine. Special thanks to @dev-kas for creating and maintaining the VirtLang project, which serves as the core foundation for this runtime environment.

License

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