attac-t Skill: Enum vs State
"Enums are labels. States are behavior."
The Decision
Use Enum when:
- Simple labels with no behavior
- 1-2 places check the value
- No state-specific logic
Use State Pattern when:
- State has behavior (methods, calculations)
- 3+ places check the same state
- Transitions have side effects
The Heuristic
Ask: "Does the state DO anything, or just BE something?"
The Quick Test
| Ask | Answer | Use |
|---|---|---|
| Do I need methods on the state? | Yes | State Pattern |
Are there 3+ places with if ($status === ...) |
Yes | State Pattern |
| Do transitions trigger side effects? | Yes | State Pattern |
| Is it just a label for display? | Yes | Enum |
Real-World Examples
See examples.md.