This article explains the internal structure of Objective‑C categories, how they are represented as structs in the runtime, the process by which the Mach‑O loader discovers and attaches them, and the distinct execution order of their +load and +initialize methods.
The article explains how Objective‑C Categories can implement a low‑overhead, type‑safe communication layer between iOS components, compares alternative patterns like DI, SPI and NotificationCenter, presents performance data, and proposes two Category‑based schemes with tooling to detect method‑name conflicts and ensure maintainable modular architecture.
The article explains Objective‑C categories by detailing their definition, compile‑time vs runtime differences, internal struct representation, how the compiler emits metadata, the loading and +load ordering process, method overriding mechanics, and the use of associated objects for adding state.
