How do the internals redefinition work?

[MatanYadaev]

Hi @antecedent, you did an outstanding job with Patchwork. I'm very impressed by the redefinition of the internal PHP functions, that wasn't implemented using namespace tricks.

Could you possibly shed some light on how you implemented it?

I was wondering about it, and did not find any explanation in the README or the website. I tried investigating the code but it seems too difficult to understand the system in a glance.

Your insights would be greatly valued. Thank you in advance!