The latest version of macOS (Catalina) includes zsh by default instead of bash. I’ve been using zsh for many years and along the way I’ve started using a handful of tools that make me more productive in my terminal. asdf (version manager) asdf is a plugin-based version manager. For example, instead of using nvm to manage node versions and rvm to manage ruby versions, you can use asdf to manage everything in one tool. Read more...

When you first start learning Clojure, you’ll eventually come across the loop/recur construct that enables you to essentially do tail recursion. Why does Clojure need to have loop/recur when you can simply use a function and call it again? Let’s say you’re writing a tail-recursive (iterative) function that calculates the nth fibonacci number. Since we’re recursing from the tail position, what’s the difference between calling the function by its name: Read more...

Many people coming to Clojure are often coming from Ruby, Python, or Javascript: These languages have their own set of web frameworks, both small and large. Examples of web frameworks are Flask and Django for Python and Sinatra and Rails for Ruby. What typically happens is they learn the basics of Clojure and want to do a more tangible project. Since the majority of people are coming from a web development background and that’s what the majority of people use Clojure for, that’s what they start with: Read more...

UPDATE: 2017-05-12 A few more thoughts have come to mind after writing the original post. I realized that I didn’t talk about the clojurescript side of things. Clojurescript provides a great alternative to plain javascript or ES6. The thing about clojurescript is clojurescript has the clojure standard library, which includes many more functions than javascript. The left-pad incident made me realize how weak a standard library javascript has. People need to write so many tiny libraries in order to get functionality that would exist in other languages. Read more...

People coming from opinionated frameworks like Ruby on Rails often become disoriented in a Clojure project. Rails, being a framework, has the code already organized for you. You just had to learn where to put your models, views, and controllers. Clojure doesn’t have a major opinionated framework like Ruby on Rails that forces you to follow its conventions. A lot of beginners get confused and have questions like the following: Read more...

Here’s the sitch: You want to learn Clojure. You don’t know which editor to use. You do research and it looks like everybody is saying emacs is required to edit Clojure. You’re wondering what your options are and if you’ll be missing out if you’re not on emacs. The problem with the many Clojure resources out in the wild is that they’re outdated. They suggest that Emacs is the only way to go when editing Clojure, which leads to you being frustrated as a non-Emacs user. Read more...

We’ve all been there. You’re hacking away on some Clojure code, making a few changes and then try to run the code in your REPL. Instead of getting the result you wanted and your tests passing, you get your worst nightmare: UnsupportedOperationException nth not supported on this type: IPersistentMap And the first thoughts that pop into your mind are: I’m not calling nth anywhere! What the hell? Then you google ‘nth not supported on this type: IPersistentMap’ and don’t get anything particularly useful and you proceed to bisect your code manually to find the problem. Read more...

I’ve been getting questions from beginner Clojure developers on how to effectively use their REPL and interactive development. Quite a few of these people are coming from languages like Java, where they would have to compile their application and wait before running any code. Integrate your REPL with your editor You must have your REPL integrated with your editor. Whether that’s a text editor like emacs with cider, or an IDE like IntelliJ with Cursive, you have to be able to evaluate code in your REPL from the editor. Read more...

HN Comments 2021: https://news.ycombinator.com/item?id=28577371 Last year, I submitted a PR to the Clojure web request routing library, Compojure. Even though I was doing Clojure full time at work, there was still a lot for me to learn and always will be. Opening a PR for an open source library I was familiar with and used all the time made me realize a few things: I didn’t know it as intimately as I thought I did. Read more...

Checking For An Empty List Don’t use (not (empty? coll)). Instead prefer (seq coll) instead. Seq returns nil if the collection is empty. If the seq isn’t empty then it returns a seq on that collection. Flattening The Result Of A Map By One Level If the result of a map function ever returns a list of lists, then use mapcat over (apply (concat (map...))): (map list (range 10)) ;; => ((0) (1) (2) (3) (4) (5) (6) (7) (8) (9)) (mapcat list (range 10)) ;; => (0 1 2 3 4 5 6 7 8 9) Maps Are Functions Maps, like keywords, are functions. Read more...