Kotlin and Variance: Navigating Type Relationships
Demystifying Generics: A Comprehensive Exploration of Type Variance in Kotlin and its Practical Implications in Software Development
If you’ve worked with a programming language that supports generic types, you’ve likely encountered terms like invariance, covariance, and contravariance. At first glance, these terms can be intimidating. However, a deeper understanding of them allows for more efficient and flexible coding. While this article uses Kotlin for illustration, the core concepts resonate across several programming languages, including Scala, Java, C#, and Swift.
The Beverage Vending Machine
Let’s begin with a simple example: a beverage vending machine. It takes your payment and dispenses a drink. While basic, this example sets the stage for our deeper dive into variance. Some machines are designed to dispense soft drinks, while others are specifically built for coffee.