What Is PXP? A Fast, Rust‑Powered PHP Preprocessor and Language Extension

PXP Overview

PXP (Extended Preprocessor) is a suite of tools and libraries designed to make programming in PHP more enjoyable and efficient. Although PHP has evolved over nearly three decades, its creators believe there is still room for improvement, and PXP aims to address some of PHP's shortcomings by providing a more modern, powerful, developer‑friendly language.

Hybrid Architecture

The core of PXP is built as a hybrid system that pairs ultra‑fast Rust code with flexible PHP code. Rust handles heavy tasks such as parsing and type inference, while PHP manages higher‑level responsibilities like code formatting, refactoring, and pretty‑printing. This dual‑language approach requires contributors to understand both Rust and PHP, but it is intended to deliver the best possible performance.

Superset Language

PXP introduces a new language that is backward‑compatible with PHP while adding modern syntax and features to improve developer ergonomics. Example features include:

Multi‑line short closures :

$add = fn (int $a, int $b) {
    // ...
};

Type aliases :

type Label = string | Closure | null;

trait HasLabel {
    protected Label $label;
    public function label(Label $label) {
        // ...
    }
    public function getLabel(): Label {
        return $this->label;
    }
}

Generics :

class Collection<K, V> implements ArrayAccess<K, V> {
    protected array<K, V> $items = [];
    public function offsetGet(K $key): V {
        return $this->items[$key];
    }
    // ...
}

Pattern matching :

$point = new Point(x: 1, y: 2);

echo match($point) {
    Point { y: 1 } => 'Y is 1!',
    Point { y: $y } => "Y is {$y}!",
};

Language Server

A language server provides editors with features such as autocomplete, go‑to definition, and refactoring. Because PXP defines a new superset language, a high‑performance, reliable language server is essential for a good developer experience, and the project invests heavily in this component.

Static Analyzer

Building a static analyzer is another key part of the project. The language server requires some form of type inference, and implementing a full static analysis engine allows the same capabilities to be reused across tools.

Formatter and Linter

To ensure code looks clean and follows best practices, PXP also includes a code formatter and linter built on the same core libraries. These tools benefit not only PXP users but all PHP developers.