I've seen various posts about Elixir's gradual type system pop up on HN, but haven't been following too closely. Does anyone know whether this particular gradual type system can change the asymptotics of programs vs untyped code? As far as I'm aware, most gradual type systems (e.g. Racket) can make programs run asymptotically slower, although there are some exceptions [1].
Elixir's gradual type system cannot change the asymptotic complexity of your programs. The design explicitly rules out mechanism that causes slowdowns in other gradual type systems (runtime casts at static/dynamic boundaries)
Most gradual type systems insert coercions when values cross the types/untyped boundary (checking every element of a list, wrapping values in typed proxies, etc) but Elixir's team published a "strong arrows" result specifically to achieve soundness without those runtime checks. The bytecode the compiler emits is semantically identical to untyped code.
Oh shit here I go (and learn Elixir for a whole year (again)) again.
I love everything about Elixir, but Elixir constantly makes me doubt myself like no other language. My brain isnt made for functional stuff, but this makes me want to try again.
Sucks that it's not really a beginner friendly ecosystem and usually, when having questions answered, people assume you already know a lot about the language.
don't let the title fool you - the first half of the book is just elixir
over the past 8 years this is the book i've used to ramp back up on elixir and it works like a charm every time - i've never finished it
for me, a mark of a good programming book in this tutorial-project style is that I have started it half a dozen times and never finished it because at some point before the end I've been equipped w/ the tools to go off and do my own thing
Yea I've worked through Elixir in Action and appreciate all book recommendations. My issue is, tutorial style books rarely cover security related concerns.
Yea I've posted there twice as far as I remember. You will absolutely get help, whether you understand the answers is a whole different story.
Elixirs community is great. Its just hard to learn because it's not yet widely adopted, there are no (non senior) roles for it and it's a lot of work understanding all the BEAM concepts. A thing just being interesting isn't enough motivation for me to learn, I need a bigger goal but with Elixir there do not seem to be any.
My last experience with it was building something with Phoenix Liveview until I noticed how easily you can hijack the websocket and just spam random commands to your server or temper with payloads (with regular webapps ive built i never had this issue). Which made me quit that project.
Fair. If you have this friction then it's not worth pursuing.
One thing that really helped me pick it up was saying YOLO and rewriting one part of the business stack from Ruby on Rails to Elixir. It taught me quickly and well.
The official guides are also great and IMO you can get through them all without a rush in two weekends. But again, if you don't want to then don't.
You can also try asking right here in this HN thread. Maybe I or others would be willing to give you a more detailed response.
When building I couldn't get "what if I have ghost processes", "what if I spawn too many processes", "what if this architecture is bad compared to...", "when to kill processes", "whats the correct restart strategy for this" out of my head... It's so confusing to build for the BEAM that I ultimately gave up on it.
Do you maybe know some Rust? I'm also not that experienced with FP languages, but Gleam felt familiar enough, due to some Rust-isms, to allow me to focus more on the concepts rather than the syntax. Granted, I spent a few afternoons with it, but if I were to pick a FP language again to wrestle my brain into submission, I'd probably go with Gleam due to familiarity.
I gave up on Rust even quicker than on Elixir haha.
But yea I know about Gleam and I did build some fourier transform stuff with Rust a while back. I like Gleam generally. I am just much much slower with FP and think its extremely inintuituve compared to, say, Go for example.
With Elixir specifically it was the learning experience I had with Phoenix. I didn't understand how a Phoenix app booted, didn't know where to edit my config.
Syntax like:
I love Elixir and Phoenix, but Phoenix especially uses a lot of compile-time macros and it can be a steep learning curve when you need to pull apart the skeleton framework to figure out how things are actually wired.
I pretty frequently find myself needing to open up the source to understand what's actually going on, the docs aren't bad but it often feels like they assume a lot of existing familiarity with phoenix.
In this example, `socket` is a compile time macro and it's being called with
and what is does is register that data with the `phoenix_sockets` attribute inside the module you called `socket` from. At compile time that gets turned into a lookup inside your module, and presumable then the UserSocket module is invoked when a websocket request hits the specified path.
Would you find it more clear if socket was called like this?
Socket is a behavior, which is like a trait or interface. MyAppWeb.UserSocket implements the behavior. It's basically a convenience over having to write a bunch of repetitive WS or long poll handling every time you want a socket like thing. Its pretty well documented https://phoenix.hexdocs.pm/Phoenix.Socket.html.
You need Beam and the Elixir. I find that really weird, because I'm used to just the language like in Python, Java, C, Rust. Not something underneath it, too.
There is no debugger. The way to debug Elixir is to print stuff to the console, like 40 years ago. No thanks.
> You need Beam and the Elixir. I find that really weird, because I'm used to just the language like in Python, Java, C, Rust. Not something underneath it, too
The beam is a VM. You get that Java requires a VM too right? It’s called JVM for a reason. And Python requires an interpreter.
> There is no debugger. The way to debug Elixir is to print stuff to the console, like 40 years ago.
That is false. https://www.erlang.org/doc/apps/debugger/debugger_chapter.ht... and you have observer. And you have a lot of other debugging tools. I hear Java has a good one and maybe it’s better (I never used it) but it’s not true there exist no debuggers for the beam.
[1] https://doi.org/10.1145/3314221.3314627
Most gradual type systems insert coercions when values cross the types/untyped boundary (checking every element of a list, wrapping values in typed proxies, etc) but Elixir's team published a "strong arrows" result specifically to achieve soundness without those runtime checks. The bytecode the compiler emits is semantically identical to untyped code.
that said, I'm a fan
I love everything about Elixir, but Elixir constantly makes me doubt myself like no other language. My brain isnt made for functional stuff, but this makes me want to try again.
Sucks that it's not really a beginner friendly ecosystem and usually, when having questions answered, people assume you already know a lot about the language.
don't let the title fool you - the first half of the book is just elixir
over the past 8 years this is the book i've used to ramp back up on elixir and it works like a charm every time - i've never finished it
for me, a mark of a good programming book in this tutorial-project style is that I have started it half a dozen times and never finished it because at some point before the end I've been equipped w/ the tools to go off and do my own thing
Sometimes posts don't get traction due to ambiguity, and some smelled like "do my homework" so people ignored them.
But every post with a genuine curiosity in it gets answered, as far as I can tell.
Elixirs community is great. Its just hard to learn because it's not yet widely adopted, there are no (non senior) roles for it and it's a lot of work understanding all the BEAM concepts. A thing just being interesting isn't enough motivation for me to learn, I need a bigger goal but with Elixir there do not seem to be any.
My last experience with it was building something with Phoenix Liveview until I noticed how easily you can hijack the websocket and just spam random commands to your server or temper with payloads (with regular webapps ive built i never had this issue). Which made me quit that project.
One thing that really helped me pick it up was saying YOLO and rewriting one part of the business stack from Ruby on Rails to Elixir. It taught me quickly and well.
The official guides are also great and IMO you can get through them all without a rush in two weekends. But again, if you don't want to then don't.
You can also try asking right here in this HN thread. Maybe I or others would be willing to give you a more detailed response.
Check this out: https://www.theerlangelist.com/article/spawn_or_not
Written by one of the very best Elixir mentors. I believe it will dispel most (hopefully all) of your doubts and clear things up.
You can always ask follow up questions for clarification, people there are generally really friendly.
But yea I know about Gleam and I did build some fourier transform stuff with Rust a while back. I like Gleam generally. I am just much much slower with FP and think its extremely inintuituve compared to, say, Go for example.
``` socket "/ws/:user_id", MyApp.UserSocket, websocket: [path: "/project/:project_id"]
```
Elixir gives you too much freedom on how to write something on a syntax level which really annoyed me.
I pretty frequently find myself needing to open up the source to understand what's actually going on, the docs aren't bad but it often feels like they assume a lot of existing familiarity with phoenix.
In this example, `socket` is a compile time macro and it's being called with
and what is does is register that data with the `phoenix_sockets` attribute inside the module you called `socket` from. At compile time that gets turned into a lookup inside your module, and presumable then the UserSocket module is invoked when a websocket request hits the specified path.Would you find it more clear if socket was called like this?
This is true perhaps compared to python or go, but not compared to Java, JS/TS, or some others.
> socket "/ws/:user_id", MyApp.UserSocket, websocket: [path: "/project/:project_id"]
Socket is a behavior, which is like a trait or interface. MyAppWeb.UserSocket implements the behavior. It's basically a convenience over having to write a bunch of repetitive WS or long poll handling every time you want a socket like thing. Its pretty well documented https://phoenix.hexdocs.pm/Phoenix.Socket.html.
Two reasons I put it aside again are:
You need Beam and the Elixir. I find that really weird, because I'm used to just the language like in Python, Java, C, Rust. Not something underneath it, too.
There is no debugger. The way to debug Elixir is to print stuff to the console, like 40 years ago. No thanks.
> You need Beam and the Elixir. I find that really weird, because I'm used to just the language like in Python, Java, C, Rust. Not something underneath it, too
The beam is a VM. You get that Java requires a VM too right? It’s called JVM for a reason. And Python requires an interpreter.
> There is no debugger. The way to debug Elixir is to print stuff to the console, like 40 years ago.
That is false. https://www.erlang.org/doc/apps/debugger/debugger_chapter.ht... and you have observer. And you have a lot of other debugging tools. I hear Java has a good one and maybe it’s better (I never used it) but it’s not true there exist no debuggers for the beam.
I am not sure what GP is objecting to.
Here's what you need to do for elixir:
Download and run the Erlang installer Download and run the Elixir installer
Here for Java: Download and run the Java SDK
And for Python: Download and run the Python installer