General Clean Code Principles
Critical Rules
G5: DRY (Don't Repeat Yourself)
Every piece of knowledge has one authoritative representation.
python# Bad - duplication tax_rate = 0.0825 ca_total = subtotal * 1.0825 ny_total = subtotal * 1.07 # Good - single source of truth TAX_RATES = {"CA": 0.0825, "NY": 0.07} def calculate_total(subtotal: float, state: str) -> float: return subtotal * (1 + TAX_RATES[state])
G16: No Obscured Intent
Don't be clever. Be clear.
python# Bad - what does this do? return (x & 0x0F) << 4 | (y & 0x0F) # Good - obvious intent return pack_coordinates(x, y)
G23: Prefer Polymorphism to If/Else
python# Bad - will grow forever def calculate_pay(employee): if employee.type == "SALARIED": return employee.salary elif employee.type == "HOURLY": return employee.hours * employee.rate elif employee.type == "COMMISSIONED": return employee.base + employee.commission # Good - open/closed principle class SalariedEmployee: def calculate_pay(self): return self.salary class HourlyEmployee: def calculate_pay(self): return self.hours * self.rate class CommissionedEmployee: def calculate_pay(self): return self.base + self.commission
G25: Replace Magic Numbers with Named Constants
python# Bad if elapsed_time > 86400: ... # Good SECONDS_PER_DAY = 86400 if elapsed_time > SECONDS_PER_DAY: ...
G30: Functions Should Do One Thing
If you can extract another function, your function does more than one thing.
G36: Law of Demeter (Avoid Train Wrecks)
python# Bad - reaching through multiple objects output_dir = context.options.scratch_dir.absolute_path # Good - one dot output_dir = context.get_scratch_dir()
Enforcement Checklist
When reviewing AI-generated code, verify:
- No duplication (G5)
- Clear intent, no magic numbers (G16, G25)
- Polymorphism over conditionals (G23)
- Functions do one thing (G30)
- No Law of Demeter violations (G36)
- Boundary conditions handled (G3)
- Dead code removed (G9)
