Keeping Routines Focused

Overview

A routine should do ONE thing and do it well. This is called functional cohesion - the strongest, best kind of cohesion.

Core principle: If a routine's description contains "and", it's doing too many things. Extract into focused routines.

Goal: Improve intellectual manageability. The more focused a routine, the easier to understand, test, modify, and reuse.

When to Use

Proactively (writing new code):

• Designing new functions/methods
• Writing routine specifications
• Naming routines (if name is vague or has "and", too many responsibilities)