I’m looking into Elixir because I think it can help us make better embedded (IoT) devices. One of the things I’m working on is a KNX-stack. KNX is an open standard for commercial and domestic building automation. [ wikipedia ] KNX can communicate connectionless and connection-oriented. The former c…

If I understand correctly, this protocol resembles the OSI model , where multiple layers are stacked on top of each other with the following properties: Each layer receives input packets and produces decoded packets for the consumer layer (the one directly on top of it). Some layers might need to p…

You may try the erlang :gen_statem . it is a fancier :gen_server with some bells and whistles that you might need. (timeout, postpone, self inserted event…)

There’s an Elixir wrapper for the :gen_statem but I haven’t used that myself: GenStateMachine — gen_state_machine v3.0.0

While :gen_statem may make the SM implementation more concise, I don’t think it helps with the general problem, that I have a GenServer that has too many responsibilities, is hard to understand and hard to test.

I suspect gen_statem would help in your case mainly because of things like internal events and event postponement. In particular, using internal events would allow you to transform code like the send_frames in handle_dispatch into a pure function that returns something like: {:next_state, :somethi…

I have an opinionated wrapper of :gen_statem that is designed to help you organize your state machine, and also marshalls the confusing gen_statem callbacks into something that looks more like a gen_server. StateServer — state_server v0.4.10 Of course, in the …

I just had a quick look at :gen_statem again. Turns out I did not understand what it does when I first looked - and I still don’t, but I’ll have a closer look. Thanks for the pointer, I’ll be back.

I just had a lot of fun building a toy-protocol based on your Functional core, imperative shell proposal. Thank you! I took the state-machine (the functional part) and the actions from the KNX-stack and removed sequence-numbers and repeat-count. (those do not effect the mechanics, just bring so…

[image] Sebb: I really like it. The core now is pure and so super-easy to test and understand. Even the annoying things like deferred events are super simple (just keep the impulse). You need to always remember that when doing any type of server in Elixir, the server itself shouldn’t have any…

[image] Exadra37: when doing any type of server in Elixir, the server itself shouldn’t have any logic I wouldn’t go that far :slight_smile: If the server is fairly small, I prefer to implement everything in the same (server) module, postponing the split until the code becomes “too large” and …

I do it from the start, unless I am only prototyping :slight_smile:

Elixir Programming Language Forum

The GenServer from hell (needs some refactoring)

Questions & Help Questions

jarimatti March 16, 2021, 9:57pm 3

There’s an Elixir wrapper for the :gen_statem but I haven’t used that myself: