purerl VS secdb

I will put in a good word for PureScript for the beam with `purerl`. It's my go-to for writing BEAM code nowadays. Notably PureScript tooling including LSP, package management, etc., just works, so you are able to just get to work in internalizing the way OTP and other Erlangy things are expressed in a statically typed, pure language.

https://github.com/purerl/purerl & https://purerl-cookbook.readthedocs.io/ for more information. Join the PureScript discord and the #purerl channel if you want help.

purerl is a compiler for turning PureScript code into Erlang code, so that you're able to write BEAM (the Erlang virtual machine) applications using it.

You've been able to write PureScript that compiles to Erlang and has perfect interop for years, via `purerl`[0]. Using it with Elixir is as simple as adding `purerlex` as a compiler and having your PureScript code automatically compile when `mix` compiles things, and off you go.

In terms of the typing itself, it's exactly what you get in all of PureScript, strict static typing with no `any` or the like. Using `Pinto`, the de facto OTP layer in PureScript your processes are typed, i.e. their `info` messages & state are typed, which means that they are all much more like strongly typed state machines than anything else.

You can see an example of a basic `gen_server` here:

https://pastebin.com/UTEfz7Wg

The differences aren't very big in terms of what you'd expect to be doing. One small thing to note is that the `GenServer.call` expects a closure to be passed instead of having the split between `gen_server:call` & `handle_call`, removing the need for synchronizing two places for your messages being sent and handled.

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

A comment to the posted-article, from "Frellus", who identifies as ex-Goldman, suggests RabbitMQ might not have been used so extensively:

Ex-Goldman person here. To the best of my knowledge, RabbitMQ was used in spots but not where reliability was critical. Instead the main message brokers were IBM MQ and TIBCO. RabbitMQ would certainly lose messages in the event of a crash, and I'm not sure it would have been used for the main message bus given the rate of events. Additionally, Erlang was used for SecDB queries quite heavily. This was the bread-and-butter of the firm (https://github.com/saleyn/secdb)