Let’s continue exploration of how to design a functional library from where we left off in the previous post. Contents * Handling Lists * Assign Types * Refactor for New Types * Implementing ListTag * Functional Takeaways * Optional Tag Exercise * Should We Write This Library?

Contents * Defining the Problem * Writing an Acceptance Test * Thinking in Morphisms * Refactoring * Defining Types * Writing the Test Case * Managing Errors

How to Convert Our Functional Design into Code —

How to Convert Our Functional Design into Code —

Pesticide: A library to write Domain-Driven Tests — I am sorry about it, but I neglected this blog recently, the reason is that I’m currently trying to write a book explaining how to write complete applications in a functional way with Kotlin. This is taking a ridiculous amount of time because I need to explain functional programming principles…

See how the new compiler can make Kotlin run faster — More than a year ago I wrote a post about GraalVM performance in Kotlin for the Java Advent Calendar 2018. It’s time to re-evaluate the results using the new GraalVM v.20.0 and with both the Community Edition and the Enterprise Edition of GraalVM. You may have heard of Graal, the…

What is a legacy system? It is old software that is very hard to maintain, to extend, and to improve. On the other hand, it is also a system that is working and is serving the business, otherwise it would not have survived. Perhaps, when it was first created, a…

Exploring the performance improvements of new Inline Types — I wrote this article for the Java Advent Calendar 2019. I am republishing it here with some minor corrections. Project Valhalla is one of the most exciting projects regarding the future of Java and all JVM. It is still in an experimental state, but in this post, we will look…

Understanding how tailrec keyword works and how to take advantage of recursion in Kotlin — It is already passed a year since I wrote the first Kotlin Pearl blog post. Thanks to everybody (and you are really a lot) who supported me and clapped or liked my posts. This post will cover: How to solve a problem using recursion How to transform Head Recursion into…