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

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