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DRY

Don't Repeat Yourself is a fundamental software engineering principle that encourages avoiding code duplication. The idea is:

"Every piece of knowledge should have a single, unambiguous, authoritative representation within a system." — The Pragmatic Programmer

danger

DRY ≠ Over-Abstraction

Be careful: too much DRY can lead to over-engineering (creating generic code that's hard to understand). Strike a balance.

Why DRY Matters​

  • Less duplication means fewer bugs
  • Easier to update/change (change in one place not in multiple places)
  • Improves readability and maintainability

Violating DRY (bad practice)​

println("Connecting to database...")
// ... more code
println("Connecting to database...") // Repeated logic

Applying DRY (good practice)​

def connectMessage(): Unit = println("Connecting to database...")

connectMessage()
// ... more code
connectMessage()