Posts tagged erlang

Aurora and Learning Erlang


Aurora’s Github repo TLDR: I learned Erlang and wrote a JSON API server called Aurora for a school project. Introduction I recently concluded a school project involving writing an Android app with “some elements of concurrency”. My group wrote a chat messaging app - a stripped-down clone of Whatsapp, but with some additional features such as message tagging, conversation notes (think Google Docs, but on a per-conversation basis), and event polling. I volunteered to write the API server that would serve the Android front-end application. I chose Erlang because I heard it was cool and I wanted to learn functional programming. It seems any blog post regarding projects written in Erlang should include performance benchmarks and an eventual (and completely obvious) conclusion as to why Erlang provides superior performance under heavily concurrent loads. Instead, I will write about my journey picking up Erlang and some other things I learned from writing Aurora. Learning Erlang, and Why People Think That Learning Functional Programming is Difficult Because it is, especially if you’re used to thinking imperatively. The soundbite I use most when talking to people is: “Imagine programming without loops”. Of course, its not as bad it sounds, and when you get the hang of it, loops will seem completely stone-age. , and will be your new best friends. The difficulty is compounded by what I call the “I Think I Know What’s Going On Wait What” effect. Because functional programs (or at least, well-written ones), can be more terse and/or expressive than their imperative counterparts, it sometimes provides a false sense of understanding. When it comes time to write something from scratch, the programmer is completely paralyzed. I was stuck in many ruts as I made my way through Fred Hebert’s excellent Erlang book, Learn You Some Erlang. The chapters on socket programming in Erlang (chapter 23), ETS (chapter 25), and Mnesia (chapter 29) were particularly illuminating. The Importance of Ripping Other People’s Code Off It wasn’t until I found some fairly basic code for a TCP server off a Github repo did I slowly begin to understand how to write my own. And even then, I experimented a lot by copying and pasting and changing each line, line by line, to get a sense of how everything came together. Beyond the initial scaffolding stage, I continued to find code samples indispensable - often finding alternative ways to achieve the same functionality, corroborating and finding the…