Software Design in Python - The State Pattern in Python - I Like How This Turned Out

🧱 Build software that lasts. Join the Software Design Mastery waiting list → https://arjan.codes/mastery. The classic State design pattern is often implemented with many small classes and heavy inheritance. In this video, I show a different approach. I start with the traditional object-oriented version and then refactor it into a generic, data-driven state machine using Python features like decorators, enums, and generics. The result is a clean, reusable engine where transitions are explicit and easy to understand. 🔥 GitHub Repository: https://git.arjan.codes/2026/state. 🎓 ArjanCodes Courses: https://www.arjancodes.com/courses. 💬 Join my Discord server: https://discord.arjan.codes. ⌨️ Keyboard I’m using: https://amzn.to/49YM97v. 🔖 Chapters: 0:00 Intro 3:24 Why This Matters 4:11 Step 1 — The Traditional Class-Based State Pattern 4:57 Step 2 — Realization: This Is Just a Lookup Table 5:21 Step 3 — Extracting a Generic StateMachine 17:35 Step 4 — Making Transitions Declarative with a Decorator 20:37 Step 5 — Supporting Multiple From States 24:05 The Payment Class Becomes Boring (In a Good Way) 25:30 When To Use This vs Classic OO 25:54 Final Thoughts #arjancodes #softwaredesign #python