[brightball]

There's no magic. It's functionality that's made possible by the BEAM. It's just one of those things that came out of realizing how powerful the runtime was for handling certain types of problems.

When you combine a couple of those bits together, you end up with this.

The only modern web problem that Elixir isn't ideally suited for is heavy number crunching. Otherwise it gives this amazing balance of efficiency, scalability, reliability, maintainability and capability that can't be replicated in any language that has a shared memory model.

[nathan_long]

> The only modern web problem that Elixir isn't ideally suited for is heavy number crunching.

I would caveat that in a couple of ways.

First, suppose you have a web app where some requests involve heavy number crunching and others don't. In web frameworks where 1 request ties up 1 OS thread, a burst of heavy requests could gobble up all your available connections. Phoenix would use one cheap BEAM process per request, and the BEAM's preemptive scheduler would ensure that other requests are answered in a timely way and that all the heavy ones continue to make steady progress. So although the heavy requests might be completed more slowly than in another language, the overall system would remain more responsive.

Second, if you have need for heavy computation or data structures that work better with mutability, it's possible to (eg) use Rustler (https://github.com/rusterlium/rustler) to implement that part in Rust. See https://github.com/rusterlium/rustler for a story about doing this.

[IanCal]

I'm of a similar view to them, this felt like lots of magic or at least lots of gotchas I can see myself hitting. I saw two function definition types (def and defp), pattern matching input then requiring a caret for the variable name (?), passing in "assigns" but then referring directly to other variable names, pipes, etc. There's a lot there compared to when I've worked in Erlang.

[lawik]

Gotchas, probably some of those. Both in Elixir and Phoenix. It is an entire language plus an entire web framework.

A lot of people find Elixir more approachable than Erlang. But I wouldn't be surprised if Erlang is technically simpler and as such potentially easier to learn. The syntax is quite foreign to most people coming from more conventional languages while Elixir reads and writes fairly conventionally.

Now Phoenix LiveView does a lot for you, so I wouldn't dismiss the claim of having some magic in there. But once someone starts to get familiar with the stateful approach the model is fairly simple and the "magic" is less mystical. A lot of the things you don't need to pay attention to would be optimizations in markup and templates and how the JS does its job. That's where a bit of magic happens.

Most of the things you mention sound like things about the language. Which I found to be very approachable and the onboarding documentation to be great.

[Ndymium]

def and defp are probably the least magical of those. def is for public functions (can be called from other modules) and defp is for private functions (cannot be called from other modules).