Unit Algebra Design

Mathematical operations on units and dimensional analysis.

Unit Dimensions

Units are organized by dimension:

Currency: USD, EUR, GBP
Percentage: %, bp (basis points)
Count: shares, units
Time: years, months, days

Algebraic Rules

Multiplication

Money * Percentage → Money
Count * Money → Money
Money * Count → Money

Division

Money / Money → Ratio
Money / Count → Money per unit
Percentage / Count → Percentage per unit

Addition/Subtraction

Same units only: USD + USD → USD
Different currencies require conversion

Implementation

class Unit:
    def __mul__(self, other):
        return self._multiply_units(other)
    
    def _multiply_units(self, other):
        # Unit algebra rules
        pass

Validation

Units are validated at:

Creation time
Operation time
Assignment time