A response to Benjamin Eberlei's post on the Feature Envy code smell, taking the refactoring one step further using Domain-Driven Design principles. By introducing a ReportingPeriod value object, the calculateReport() function is freed from period calculation responsibilities, adhering to the Single Responsibility Principle. The post demonstrates the Whole Value pattern, showing how grouping DateTime and a days integer into a single value object improves cohesion, reduces duplication, and allows the code to express the Ubiquitous Language of the domain — with explicit factory methods for months, quarters, and years.
