eqwalizer VS rustic_result

I don't think the implementation itself is at fault, but yes, I do think that the design of dialyzer makes it an (at times) faulty type checker. The unfortunate reality of a type checker that fails sometimes is that it makes it mostly useless because you can never trust that it'll do the job.

To be clear, I've had it fail in a function where I've literally specced that very function to return a `binary` but I'm returning an `integer` in one of the cases. This is a very shallow context but it can still fail. Now add more functions, maybe one more `case`.

I think an entire rethink of type checking on the BEAM had to be done and that's why eqWalizer[0] was created and why Elixir is looking to add an actual sound, well-developed type checker. Gleam[1] I would assume is just a Hindley-Milner system so that's completely solid. `purerl`[2] is just PureScript for the BEAM so that's also Hindley-Milner, meaning it's solid. `purerl` has some performance issues caused by it compiling down to closures everywhere but if you can pay that cost it's actually pretty fantastic. With that said my bet for the best statically typed experience right now on the BEAM would be `gleam`.

0 - https://github.com/WhatsApp/eqwalizer

1 - https://gleam.run

2 - https://github.com/purerl/purerl

While it's not static-typing, compile-time type checking for Erlang have come a long way: Eqwalizer works pretty well - but I may be biased since my employer sponsors the project.

1. https://github.com/WhatsApp/eqwalizer

Note there is also research happening in this area by the Elixir team. The WhatsApp is also working on static types for Erlang, which I am certain will be available for Elixir too at some point.

From the discord blog posts it seems that elixir powers the chat system, with rust and python as the other two main languages in their stack.

As for whatsapp, they are mainly a erlang shop and yesterday they open sourced a type checker for erlang:

https://github.com/WhatsApp/eqwalizer

Self promotion moment:

If you enjoy the Result/Either type and API in Rust, I made this project just for this: https://github.com/linkdd/rustic_result

I also made https://github.com/linkdd/rustic_maybe/tree/main for an Option/Maybe type.

NB: Those are not types, but I'm waiting for set theoretic types to update those libs :)

It's missing the Erlang/Elixir pattern of returning a tuple `{:ok, T}` or `{:error, E}`, where we can then use pattern matching, or `with` expressions, etc...

To be fair, it is very similar to a `Result` type, which is why I made this library a while ago: https://github.com/linkdd/rustic_result

I intend to add a pipeline operator similar to Elixir, to be used with an std::result module which will provide functions to ease writing such complex code. I may take inspiration on an Elixir library I wrote a while ago: https://github.com/linkdd/rustic_result

A while ago, I made this library https://github.com/linkdd/rustic_result

I also made a library for working with `{:ok, value}` and `{:error, reason}` in Elixir: https://github.com/linkdd/rustic_result

Thanks to the pipeline operator and pattern matching, it makes pretty easy to read pipelines. It does not completely replace the with statement (that was not the point) but it simplified a lot of code.