Overview
Want to master Finite State Machines through practical examples? This by-example guide teaches FSM through annotated code and diagram examples organized by complexity level.
What Is FSM By-Example Learning?
FSM by-example learning is a code-first approach where you learn through practical implementations of state machines rather than narrative explanations. Each example shows:
- State diagrams - Visual representation of states and transitions
- Working code - Runnable implementations showing FSM in practice
- State transitions - How events trigger state changes
- Guards and actions - Conditional logic and side effects
This approach is ideal for developers who want to implement robust state management using finite state machine patterns.
Learning Path
The FSM by-example tutorial guides you through examples organized into three progressive levels, from simple state machines to complex hierarchical patterns.
Coverage Philosophy
This by-example guide provides practical coverage of FSM through annotated examples. The focus is on implementing state machines, not just theory.
What’s Covered
- Basic FSM - States, transitions, events, initial and final states
- Guards and actions - Conditional transitions, entry/exit actions
- Hierarchical states - Nested states, state composition
- State patterns - State pattern, strategy pattern integration
- Real-world applications - Order processing, user authentication, workflow engines
What’s NOT Covered
- Formal automata theory (see by-concept tutorials for theoretical foundations)
- Framework-specific implementations (XState, Statecharts libraries)
- Complex statechart extensions (orthogonal regions, history states)
Prerequisites
- Programming experience in any language
- Understanding of control flow (if/else, switch)
- Familiarity with object-oriented patterns
Structure of Each Example
Every example follows a consistent format:
- Brief Explanation: What FSM concept the example demonstrates
- State Diagram: Mermaid diagram showing states and transitions
- Annotated Code: Implementation with inline comments
- Example Execution: Sample input and state changes
- Key Takeaway: The core FSM principle to retain
This structure provides visualization, implementation, and understanding all in one place.