The birthday greetings kata

A refactoring exercise to learn about dependency inversion and hexagonal architecture. Inspired by a blog post from Matteo Vaccari. You can find the original repo here.

Solution

I decided to solve the problem in a functional programming style using the Kotlin programming language and Arrow, a functional companion to the Kotlin standard library.

Resource

The following resources helped me in designing this solution:

• Functional and Reactive Domain Modeling
• Domain Modeling made functional
• Dependency rejection
• Self-contained example of testing with modules and Arrow FX