Functional Programming

I’m documenting my journey from functional neophyte to (hopefully) functional programmer by writing a series of blog posts on the topic. So far I’ve covered what functional programming is and why you would want to learn about it. In this post, I’m going to describe the resources I will be using to become functionally fluent. Although I have previously said I’m learning about functional programming, I should be more specific. I do already have some middling experience with Clojure and Lisp, but I have too many battle scars from running dynamic languages in production to go down that path again. At this point in my career, my experience dictates that any new code I write will be statically typed. Because of this bias, I’m going to approach learning functional programming through the lens of statically typed functional languages. My learning plan will reflect that and help narrow the scope of this project. ...

I previously talked about what functional programming is by comparing it to other programming paradigms. This post expands on that post to talk specifically about practical differences between functional programming and the paradigm most of us are intimately familiar with — imperative. This post is punctuated with some quotes from the book An Introduction to Functional Programming Through Lambda Calculus. It’s worth noting that each of these practical differences are enabled because of the power of referential transparency. ...

Having covered what functional programming is, I wanted to spend a minute or two discussing why I want to learn functional programming in the first place. I’m sure we have all heard vague things about “side-effects”, “immutability”, and “composition”, but I wanted to dive a bit deeper on the topic to describe what — to me — is important about functional programming. Referential Transparency The key differentiating feature of (pure) functional programs is that they provide referential transparency. An expression is said to be referentially transparent if it can be replaced with its corresponding value without changing the program’s behaviour. ...

I’m documenting my journey from functional neophyte to (hopefully) functional programmer by writing a series of blog posts on the topic. This is the first post describing what, exactly, the word functional programming means. Functional programming is a programming paradigm that lives alongside other programming paradigms. None of these paradigms have a precise, unanimous definition or standard, and there is not real agreement on which paradigm is better or worse for building particular types of software. ...