How Ruby's Method Lookup Really Works Beneath the Object Model

A developer article argues that the common belief that Ruby objects contain their own methods is misleading. Examining CRuby's internals, it notes that an object holds only its instance variables, internal flags, and a pointer to its class. Methods are stored in a method table belonging to the class, which Ruby searches when a method is called. This shared structure keeps memory use efficient, since many instances reuse one table. The piece also explains how defining a method on a single object works, through a hidden eigenclass that Ruby creates behind the scenes.