Goodbye, Joe

All Erlang enthusiasts will have their flags at half-mast this year, as 2019 is the year we say goodbye to the father of Erlang, Joe Armstrong. For those who never met him, many of his conference talks online will offer you much delight. And for those whom he inspired, it’s a solemn month of April, indeed.

When I first started writing Erlang, the Erlang origin story as told by Joe was as good as the language itself: a language conceived at Ericsson’s Computer Science Lab; brought about via first principles to solve massively concurrent systems a decade before the World Wide Web. I never tired when Joe would share how Erlang came about. There was something contrarian about Erlang that I loved — a language that was dynamic, strongly typed, with single assignment variables. In Erlang, ‘A’ was ’A.’ ‘Finally, someone has restored sanity,’ I would say.

Joe’s books hinted at how the man was wired. Early in my Erlang hacking, I found chapter seven in Joe’s ‘Programming Erlang’ to be something I would read and re-read. For me, this language wasn’t just a language, it was a philosophy:

We don’t have shared memory. I have my memory. You have yours. We have two brains, one each. They are not joined together. To change your memory, I send you a message: I talk, or I wave my arms.

Joe reminded me that in life, and in programming, communication is everything. Moreover, people, like Erlang processes, can’t read minds. We have to assume nothing about others; it’s up to us to relay information as clearly and explicitly as possible.

This is my ‘Staussian Reading’ of it all. And this isn’t even the more famous of Joe’s mantras. Joe would say: ‘Let it crash.’ Unpacking this little shorthand of Joe’s is easy to do, once you understood what Erlang was all about. (Of course, if your language didn’t have a robust concurrency model built right in, you could say ‘Let it crash’ all you wanted, but you’d just be playing air guitar.)

Among many other things, Joe was a musician, entrepreneur, physicist, and scientist in the proper 19th-century meaning of the word. His conference talks were entertaining and insightful. There was a performance element to his talks. His giddiness, mixed with ideas more commonly found in what an old-world alchemist might dream up, were unlike anything else. Joe Armstrong was an inspiration, and will be dearly missed. Goodbye, Joe.