What are the most important features Elixir has for you and why?

Can’t decide the top 3, but the most important feature for me: It solves concurrency. I find it quite astonishing, Erlang introduced a perfect solution 33 years ago, for problems that are still a huge issue in many modern programming language. There are even frameworks trying to rebuild something similar in other languages, like https://getakka.net/ for c#.

Hmm, so maybe this is already 3: The lightweight processes, the supervisors, the process communication via messages.

I like fault tolerance. Trying to explain to non-erlang/elixir programmers how your software can fix itself when it fails is fun.

You can connect to a live system, debug, repair without stopping the service.

You can play with processes, and see what happens when You kill them

So my list is

• Concurrency
• Fault tolerance
• (Soft) Real time

The last one being more personal, and more Phoenix, as I can build reactive web with channels.

• Immutability, i.e.

  old_a = a
  foo(a)
  a == old_a
  

  This is enormous help when analysing and reading code, as “what I see is what I get” and I know that (in most cases) there will be no magic behind scenes that could change behaviour of my code.
• Application servers done right. I can run multiple (OTP) applications within the same VM without problems. So I get everything what is best in application servers and at the same time I get hell lot of different nice properties, like proper fault tolerance.
• Distribution of the system - I can easily configure VMs on different machines to be transparently treated as one. No need for external tooling (except epmd replacement).

• Immutability. Reduces bugs and frees you from safeguarding by deep copying or the likes.
• Pattern matching. Makes it much more convenient to extract values e.g. deep inside a JSON structure.
• Simple and consistent language core. Relatively small set of language concepts. It won’t take you a lifetime to be productive in the language.

The runtime’s support for concurrency and fault-tolerance is an added bonus of course.

1. Not really related to the language per se, but I do think that asking how involved with the community a candidate is is really telling. Have been to any conference or meetup ? So you participate in forums ? Have you ever wrote or publish something on the subject ? I think that shows you how commited they are.

2. How Elixir / Erlang solve concurrency

3. What sets Elixir and functional programming apart from other languages and paradigms