Not OP but: https://phptherightway.com/pages/Functional-Programming.html https://phptherightway.com/pages/Functional-Programming.html https://github.com/mtdow

Not OP but: https://phptherightway.com/pages/Functional-Programming.html https://phptherightway.com/pages/Functional-Programming.html https://github.com/mtdowling/transducers.php https://github.com/mtdowling/transducers.php Don't forget putting a function into a function, gives you behaviour polymorphism at runtime, without inheritance or class based dependency injection