I've never followed Elixir particularly closely, but what I saw in some Erlang discussions was different. Discourse there was that you need to gracefully handle failure anyhow, so type errors can (should?) just get handled by the failure recovery machinery you're supposed to have anyhow. I disagree with that point of view, but it's much more defensible than "$LANGUAGE is magic".
He gives a lot more nuanced take than 'types are useless', which is more like 'types are less useful than people think in the context of Elixir development'. (Which makes sense because he's in the middle of implementing a type system for Elixir.)
With no insights at all into Elixir this sounds like a reasoned and defensible, if not outright correct, position.
The proposition I'm working with is "types are more useful than people think in managing a horde of degenerate short-cut taking co-workers whose failures I will be blamed for openly and quietly regardless of actual fault". Gradual typing is an interesting and appealing compromise, I'm gonna have to give Elixir a serious try.
Compile-time checks don't obviate the need for runtime error handling, and I love the robustness of Erlang's runtime error handling. However, that doesn't change the fact that we should be catching and handling errors as early as possible, and there's a whole bunch of logic errors that you can easily catch at compile time.
Since any node in a cluster can be updated at any time and Elixir/Erlang code on the BEAM is designed make it easy to pass function calls to other nodes you don’t have any way of guaranteeing the Type contract between nodes. Types create a sort of false confidence in those situations where pattern matching handles everything very cleanly.
Example: You may not need to match on a full type, just a specific element name in a hash.
When people say Elixir doesn’t need types it’s not claiming that types are without value. It’s a claim that the mechanisms that already exist are enough without the added complexity.
I appreciate the gradual approach so that we can lean on both.
I've seen internet commenters say China is overstating its economic numbers to look more intimidating, and that China is understating its economic numbers to receive more favourable WTO trading terms, but somehow these two camps never called each other out, which makes me think they're the same people believing that China is both overstating and understating.
The thing you DO hear a lot, though, is that you don't need to worry about bugs nearly as much as you do in other languages. But that's not because Elixir is "magic", rather, it comes from Elixir's runtime (Erlang/BEAM) providing best-in-class fault tolerance primitives like lightweight process isolation and supervision trees.
In practice that means the blast radius of bugs is generally tiny and any resulting crashed processes are often recoverable. The phrase you often hear is "let it crash", since the effort that goes into exhaustive defensive programming is usually more costly than the bugs you'd be trying to prevent.
Maybe the things that made this transition feasible are the "magic" that used to make people say "Elixir doesn't really need types". Maybe what they meant was something like "Elixir is an orderly language in a bunch of ways that makes the lack of static typing less painful to me than usual".
And I guess we'll see how much people get out of this when they add type annotations later. Maybe the value add will be big after all, and then they'll really be proven wrong. But I can sort of imagine how the apparent contradiction fits together.
BASIC, Smalltalk vs Strongtalk, Common Lisp, Dylan
It is the eternal September.
So it is possible new theory was actually needed to preserve everything that was judged more valuable than types.
In any case, most of these questions are starting to become less relevant as we switch to having robots doing the programming instead.
Now the question is how to typecheck natural languages.
It’s possible that position was correct before set-theoretic type theory was developed.
and to that point around typing feels like the same wish-washy hand waving from the community that is very off putting
BEAM has genuine use cases but its not as wide as its made to believe. There are very good places where that is a perfect fit but it simply cannot upend Typescript.
Elixir feels very similar to how Clojure started getting traction and then ultimately forgotten apart from its die hard fans, I'm not saying Elixir will go the same way but seems very hard for something new and bold to replace what is popular and boring.
I do want Elixir to succeed (also Clojure as well and I advocated for it for a bit) but the low number of jobs still puts it in similar proximity to Clojure but BEAM I think would still provide uplift where Clojure simply could not
I maintain more than 20 packages and, except for the major ones, like Phoenix and Ecto, they haven't been updated in more than a year and yes, they are all fine.
The language has been extremely stable. There has been almost no breaking changes in over a decade. Case in point: we introduced a whole gradual type system without making any changes to the language surface! The language is still on v1.x!
You think all software breaks every 6 months, what happened Im curious
Or even that, the very same ecosystem congratulates themselves on the typing system but still relies on linters because the language and runtime themselves allow whole categories of dumb ideas to be written?
Unfortunate, since it's one of the flagship Elixir packages, but I think the upgrades are worth the trouble. Better to improve something than to leave it broken solely for the sake of legacy compatibility IMO.
Then eventually they add static types. Happened to Python, JavaScript, Ruby... I'm sure there are more.
Statically typed languages put the onus on the caller to transform the data into the shape(s) required.
Dynamically typed languages put the onus on the called to handle anything.
That is, in a dynamically typed environment your function has to defensively code for every possible type it could be handed.
It's not about that at all. Static types give you errors reliably at compile time instead of randomly at runtime, better documentation of what the code expects (people writing dynamically typed languages eventually resort to type comments), working IDE support, reliable refactoring and better code, all of which results in faster development.
The cost is a more complex language, occasionally difficult-to-write types, and very occasionally impossible-to-write types. But those are very very minor in comparison to the pros.
This has never been an issue in Elixir, because instead of a comment, you'd just improve the pattern matching in the function definition.
def blah(%{students: [%{firstname: firstname, lastname: lastname}|[]], count: cnt}) when is_int(cnt):
fullname = firstname <> lastname
Really? All the Elixir fans were saying that?