README

Corefill is a high-performance C-based polyfill extension for PHP, designed to provide missing core functions, language features, and standard library behavior across different PHP versions — implemented natively in C for speed, consistency, and lower memory overhead.

Unlike userland polyfills written in PHP, Corefill operates at the Zend Engine level, offering near-native performance and deeper integration with PHP internals.

Why Corefill?

Popular polyfill libraries (such as Symfony Polyfills) are written in PHP. While extremely useful, they:

Add runtime overhead
Increase memory usage
Cannot hook deeply into Zend internals
Behave differently than true core implementations

Corefill solves this by implementing polyfills directly in C.

Key Advantages

⚡ Native performance
🧠 Lower memory usage
🔧 Zend Engine–level integration
🔄 Consistent behavior across PHP versions
🧩 Drop-in replacement for missing core features

Goals

Provide missing PHP core functions in older PHP versions
Backport newer PHP features where feasible
Offer consistent behavior across 8.x, and beyond
Act as a foundation extension for other C extensions
Reduce dependency on heavy userland polyfills

What Can Be Polyfilled?

Corefill focuses on features that are:

Frequently polyfilled in PHP userland
Performance-critical
Safe to implement in C

Examples

Missing core functions
String helpers
Array helpers
Hash / crypto helpers
Language behavior adjustments
Internal constants
Engine quirks across versions

Supported PHP Versions

PHP Version	Status
PHP 8.0+	✅ Supported
PHP 8.1+	✅ Supported
PHP 8.2+	✅ Supported
PHP 8.3+	✅ Supported
PHP 8.4+	✅ Supported
PHP 8.5+	✅ Supported

Installation

pie install mailmug/corefill

https://github.com/php/pie

From Source

git clone https://github.com/yourname/corefill.git
cd corefill
phpize
./configure
make
sudo make install

mailmug / corefill

Maintainers

Details