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Sep 22, 2021 · Fundamentals

Understanding Finite State Machines and Their Implementation in Swift

This article introduces finite‑state machines, explains their mathematical definition and classification, demonstrates a simple metro‑gate example, and provides two complete Swift implementations—one using object‑oriented design with protocols and classes and another using a functional style with generic transition structs and thread‑safe queues—followed by a real‑world keyboard‑state use case.