Functors in scala

A coworker of mine and I frequently talk about higher kinded types, category theory, and lament about the lack of unified types in scala: namely functors. A functor is a fancy name for a thing that can be mapped on. Wanting to abstract over something that is mappable comes up more often than you think. I don’t necessarily care that its an Option, or a List, or a whatever. I just care that it has a map.

We’re not the only ones who want this. Cats, Shapeless, Scalaz, all have implementations of functor. The downside there is that usually these definitions tend to leak throughout your ecosystem. I’ve written before about ecosystem and library management, and it’s an important thing to think about when working at a company of 50+ people. You need to think long and hard about putting dependencies on things. Sometimes you can, if those libraries have … Read more


A response to “Ten reasons to not use a functional programming language”

If you haven’t read the top ten reasons to not use a functional programming language, I think you should. It’s a well written post and ironically debunks a lot of the major trepidations people have with functional languages.

But, I wanted to play devils advocate here. I read a lot of articles on functional and everyone touts a lot of the same reasons to use functional languages, and this post was no different. What these posts always lack, though, is acknowledgement that functional isn’t the end all be all of language solutions. It has plenty of problems itself, and it’s just as easy to critique it using the same ten reasons. That said, I wanted to address a few of my opinions regarding functional programming using the same format as the original article.

Reason 1: I don’t want to follow the latest fad

The authors point here is that … Read more