Elm ports with Nim

Show and Tell
1

Nim compiles to JavaScript and I’m using it with Elm. I might publish this on nimble

type
    Module* {.importjs.} = ref object of JsRoot
    Program* {.importjs.} = ref object of JsRoot
    SubPort*[T: JsRoot] {.importjs.} = ref object of JsRoot


# Initialize a Program (doesn't work with flags or Browser.element)
proc runModule*(
    name: cstring,
): Program {.importjs: "Elm[#].init()".}


# Subscribe to a Cmd port (from Elm)
proc subscribe*[T: JsRoot, Output](
    program: Program,
    name: cstring,
    onTrigger: proc(payload: T): Output,
) {.importjs: "#.ports[#].subscribe(#)".}


# Get a reference to a Sub port (to Elm)
proc getSubPort*[T: JsRoot](
    program: Program,
    name: cstring,
): CmdPort[T] {.importjs: "#.ports[#]".}


# Send a value through a Sub port
proc send*[T: JsRoot](
    subPort: SubPort[T],
    payload: T,
) {.importjs: "#.send(#)".}
2 Likes
2

May I ask why you are doing this? What are you using Nim for?

1 Like
3

My project (dullbananas/editsc) has a lot of code outside of elm (elm is not good enough with performance), so writing javascript directly would be a pain in the stdout.

Typescript has a slow compiler and is not very flexible. Rust (with webassembly) is good but there’s some limitations with javascript ffi.

Nim is a good programming language with sexy expressive ffi, optimizations like compile-time evaluation, macros, uniform function call syntax, etc.

4

It’d be great if you could provide a little full stack demo.

Nim got on my radar recently. From what I gathered there’s a difference between procs and funcs where one of the two disallows mutations which I thought was a very interesting language feature.

One could then imagine enforcing mutation being isolated to one area of the code base rather than spreading it.

Via a simple pre git commit hook and shell script.

I’d be interested to hear your thoughts :wink:

1 Like
5

I’ve been using Nim a bit more and I’m actually hating it.

  • The cryptic compiler error messages are the opposite of Elm’s
  • Unsafe. For example, var statement without a value causes it to be 0-initialized which is not explicit and often done accidentally
  • No result/maybe types. In Nim I have to use exceptions (like python) :face_vomiting:
  • Library documentation isn’t often good

I’m gonna just use Rust and make a better alternative to wasm-bindgen

6

If you work on better Rust-elm interop I’m also interested in what you’ll do. For the time being I’ve just been piling up ports and hand wiring the different parts between rust and elm.

7

This topic was automatically closed 10 days after the last reply. New replies are no longer allowed.