Inside Ruby’s Object Model

A deep dive into how MRI/CRuby implements Ruby's object model at the C level. Covers how include inserts T_ICLASS proxy nodes (sharing method tables rather than copying), how prepend rewires the ancestor chain via an origin node, how extend is simply include on a singleton class, and how class methods are singleton methods on class objects. Also explains the parallel singleton class hierarchy that enables class method inheritance, the full method resolution order (MRO), and how refinements work as scoped monkey patches. The post traces these mechanisms through MRI source files like object.c, class.c, and vm_method.c.