[not-much-io]

I've gotten into elm recently coming from Clojurescript and reagent (re-frame to be exact).

I didn't think I needed types, until I tried Elm, now I am seriously having an identity crisis..

All my backend Python code is also riddled with type hints to help out with the cognitive load.

Elm - Simple, friendly, helpful

Just wish Elm was more mature, but loving it anyway!

[agentgt]

For me it boils down to variant types (also known as Algebraic Data Types but I prefer the ML nomenclature) and the corresponding pattern matching that comes with it. This is IMO the major feature that makes FP languages so damn safe.

Everyone talks about higher order functions and generic types but lots of languages have that.... the really good ones have ADTs.

Oh what I would give to have ADTs in Java. I would stop using Exceptions for errors (not all exceptions are bad just most of them). I would stop using the annoying visitor pattern... That reminds me that I need to rexamine Derive4J

[sanderjd]

I had a similar epiphany when I started using Rust. I hadn't really understood the power of ADTs, having only come across them in Haskell, until I saw them in an otherwise more familiar language, and it totally changed the way I think about things.

[drudru11]

Have you looked at the Yeti language for the jvm?

[supster]

It would be really cool to have an Elm type language on the backend. Elm feels like a lighter, friendlier version of Haskell.

[jarcane]

Whereas after spending even a day with it I found myself wanting to run screaming back to Haskell.

No typeclasses, no monads, more primitive pattern matching, no guards, use of massive nested elseif considered idiomatic ...

Simple tasks wind up feeling tedious because so many of the standard tools and patterns of any other ML language are simple missing completely. The result feels like trying to work with one of those random toy Lisps people make in a weekend and throw up on Github.

It frustrates me, because in theory I do like the concept of the Elm architecture, I love ML-style type systems, and I work with reactive programming every day in ClojureScript. But the language it's attached to is so incomplete that it quickly just becomes a pain.

[noelwelsh]

That's exactly the dividing line I see in those who love Elm and those who don't. People coming from Ruby / JS backgrounds appreciate a modern type system and it isn't so different from languages they are used to that it is hard to get going. People already used to modern functional programming miss the abstractions they are used to that Elm doesn't provide. I find this really interesting. As a community we don't give enough attention to the sociological aspects of programming. You can see similar things in the adoption of languages like Go and Elixir.

[lolive]

(Sorry for my poor english but i need some clarification) Do you put Go, Elixir and Elm is the same bag, i.e langages a step further JS in term of abstraction, i.e langages easy to understand when you come from plain JS? And then, you put Purescript and Haskell in another bag, i.e langages with advanced abstractions absent from "casual" langages, i.e langages requiring a lot of effort to learn? Did I summarize your idea correctly?

[a-saleh]

I think understood the Elm/Haskell/Purescript, i.e:

Javascript dev sees Elm and might think "Wow,a type-system and it is awesome, didn't expect that"

Haskell dev sees Elm and might think "I am missing so many features with these types" and consider something else, probably pure-script, that has similar toolbelt.

Not sure about the rest though.

[noelwelsh]

a-saleh is correct. Regarding Go and Elixir, I think Ruby / Python seem them and think "wow, I can program in a familiar style and I get performance and concurrency!" Haskell etc. people look at them and think "this smells."

[pka]

Look no further! Try Purescript. It's basically Haskell (albeit strictly evaluated) and has everything you listed, plus a record system I really wish Haskell would adopt.

I'm currently using it in production with purescript-thermite, a thin wrapper over React, and it's worked out great.

Elm is great for people coming from JS, but not so much for people coming from Haskell.

[jweir]

Have you looked at Reason from Facebook? It is a syntax for OCAML that is a bit simpler - https://facebook.github.io/reason/

[masklinn]

MLs are fairly close I would think, Elm is syntactically very similar to Haskell but semantically it feels closer to SML or OCaml (without the O part)

[vog]

That was my first thought, too: Elm is quite similar to OCaml, so why not using OCaml in the backend? With all that server-side stuff around MirageOS, you can not only build a server app, but a full server VM within OCaml.

On the other hand, OCaml also targets JavaScript coding in the browser, via js_of_ocaml or the newer bucklescript.

I would be very interested in a comparison of client-side development with OCaml+js_of_ocaml (or OCaml+bucklescript) versus Elm.

[weavie]

Yes. SML really deserves a lot more love.

[dreamdu5t]

There is one: PureScript. You can build node apps with it and use it with webpack. There's even an Elm-like UI library https://github.com/alexmingoia/purescript-pux

[jjnoakes]

I'm toying around with PureScript on node. It's not too bad.

[not-much-io]

From what I understand Elm is planned to target Node eventually. However the language is pretty young right now and the main work is going into making client side Elm the best it can be. The language author doesn't want to branch out too far.

[hibikir]

Not quite: It's planned to target Beam, Erlang's VM. It's an easy fit for Elm. Still, not going to get done any time soon.

[ryanplant-au]

Elm on Beam would be some kind of beautiful dream.

[twoquestions]

Do you have a source for this? I'd be interested in their reasoning.

You'd think Beam would be a very different compile target than JS, and it seems weird to make such a huge change without very good reason.

[pmarreck]

I think "massive concurrency" and "bulletproof uptimes" are pretty good reasons. Plus that would then allow Elm on both client and server.

The Elm folks have been fairly buddy-buddy with the Elixir/Phoenix folks, so this doesn't surprise me

[twoquestions]

That sounds amazing.

It makes my heart sing that a different VM than JVM or .Net is gaining more traction, and as a static types fan it makes me happy that a statically typed language may be getting on Beam.

[adam_albrecht]

Richard Feldman (who works with Evan Czaplicki at NoRedInk) mentioned it in the Elm slack channel.

http://i.imgur.com/pqk9oMl.png

It will definitely be a very different compile target. But Elm really doesn't take any inspiration from Javascript, so I don't think it will change much about the fundamentals of the language. Of course they'll need to add capabilities for concurrency, OTP, etc.

[knewter]

I think the compile target is basically not a big problem, and there's been explicit work to make the Browser just one Platform. Also, see the `Process` module in the core docs for a hint of the future, regardless of where it lands (this would also work well for WebWorkers etc, and is handled right now by a naive scheduler). Concern over the compile target should be super low - if you've built a language of sorts, you should have a feel for how it's not that big of a deal to tweak the target.

[jtwebman]

This is a great idea as Beam doesn't force typing like JavaScript so it would be a great add. I wonder how they are going to tie in OTP?

[TheWiseOne]

F# might be worth considering. You can also target JS by using a compiler like Fable (http://fsprojects.github.io/Fable/) or FunScript (http://funscript.info/).

[clarus]

You can get a "kind of Elm" experience on the backend with Flow and JavaScript / NodeJs. The type system of Flow is not as strict as Elm, but you have the main parts (including disjoint unions) and can use existing JavaScript code. With React and Redux you also get a similar framework for the frontend.

[BenoitP]

I have been thinking about toying with JVM's Graal compiler (JIT and customizeable deopts for the price of an interpreter). But with a language that has few corner cases. I was thinking maybe regexes, or brainfuck, or QBasic.

I'd just looove to try and put Elm on the JVM, but I just can't at the moment.

[kawera]

Elixir seems a good candidate.

[nilkn]

I'm not sure. I do think Elixir is a great language given its goals, but it's very dynamic, whereas Elm is strongly statically typed.

[rdtsc]

Elixir and Erlang have a type checker as well. Not Hindley–Milner but one called "success typing" and is checked by a tool called Dialyzer. It is rather good actually:

http://learnyousomeerlang.com/dialyzer

But is still optional to compile. The more precise and better the type annotations, the more helpful it is. If it can deduce that some inconsistency or type error occurring it will let user know. If it is not sure, it won't say anything.

Another point is because of isolated process heaps and extra fault tolerance, it is possible to get a high degree of assurance from a system built in Erlang or Elixir even with dynamic typing. And there are certainly many examples of that.

[nilkn]

Dialyzer is indeed nice, but as you say, it's completely optional, it's not Hindley-Milner, and it relies entirely on thorough, correct type annotations from the developer.

Elixir also follows the Ruby philosophy of hiding as much behind the syntax as possible, whereas Elm tends to be very explicit. So I stand by my point that Elixir is a very different language in practice from Elm.

[The_suffocated]

> Elixir also follows the Ruby philosophy of hiding as much behind the syntax as possible, whereas Elm tends to be very explicit.

This is not true. While Elixir may not make things as explicit as Elm (I don't know Elm well enough to assert or refute such a statement), the author of Elixir has stated in various occasions that Elixir prefers explicit to implicit.

For instance, in Elixir, unless one explicitly defines a String.Chars protocol for a data structure, string interpolation of that data structure will not compile. In contrast, pretty much everything can be implicitly interpolated in Ruby.

Another example is function calls. In Elixir, if f is not a named function but a variable bound to an anonymous function, you cannot call it by writing something like f(x). Instead, you must put a dot after f and write f.(x) to state clearly that you are calling an anonymous function.

[rdtsc]

I use Erlang and I like it a bit more than Elixir in general exactly because it is more explicit. It involves slightly more syntax but there is less hidden magic stuff happening behind the scene.

[kawera]

You are right about the type system but still, Elixir is a lighter, friendlier functional programming language compared to haskel or erlang. Not having previous FP experience, I'm having a good time learning Elixir + Elm.

[dllthomas]

Compilation targets for typed languages are very frequently untyped (think ASM, for the most canonical example) - it is neither weird nor difficult.

[nilkn]

Could you clarify? I don't immediately see the relevance of this. Why does it matter if the compilation target is or is not also strongly typed, and how does that imply anything about the experience of using a high-level dynamically typed language vs. a high-level statically typed language?

[dllthomas]

I understood the (some number of grands-)parent comment to be saying "Elixir seems a good candidate [for a compilation target]." If that was not your interpretation, then it is certainly non-sequiter. Re-reading, I think I misread something in a surrounding comment, though I'm not sure what.

[wyager]

Elm is essentially just Haskell with weaker type classes. If you can use Elm, I can't imagine why you'd have trouble using Haskell.

[zem]

you should enjoy this blog post on thomas leonard's experience porting 0install from python to ocaml: http://roscidus.com/blog/blog/2014/02/13/ocaml-what-you-gain...

[shados]

having types vs having good types is two totally different world. Elm's type system is really awesome. Interaction of simplicity and power.

I kind of like to think of it as the Java to late 90s' C++, where "less is more" made it popular.

[shrugger]

Scala.js is a lot of fun, have you considered using it? It's quite further along than Elm at this point.

[not-much-io]

The reason I personally haven't looked at Scala (or Scala.js) is the OOP + FP approach.

<personal understanding> Scala seems to want to please everyone, having all the tools at hand - Immutable and Mutable collections, Objects and enforced Pure Functions etc.

That to me seems like a call for trouble in the community, a split between approaches to problem solving at a fundamental level. </personal understanding>

And well one of the things that I love about Elm is the lack of needing to make too many choices because the language doesn't have too many complicated features and prioritises "One good lib over 5 decent libs" (though at this young stage what other option does it have).

Clojurescript, Javascript and I'm betting Scala.js offer a lot of solutions to the same problem and/or have fancy language features that I am looking for an escape from. Just personally want to try going back to "less is more", to see what it is like. :)

[shrugger]

Well, Scala was originally designed to complement a platform that encourages mutable data structures. When Scala was first getting started, Java didn't have anonymous functions yet, and it was a different time.

Currently, Scala-Native is working on off-JVM Scala, Scala.js is already plenty capable of compiling to efficient JS, and when wasm lands, it'll probably manage that rather easily.

Elm is a neat language, but I think it sort of presents too wide a divide. I have the same problem with Elm as I do with Typescript, Dart, and all of the other languages that recognize JS is a shit language, but just compile to it anyways.

Scala is a VERY well-designed language, and FP/OOP isn't nearly as polarizing as it might seem. I'd recommend LearnXinY Scala, read a little bit and you might see how natural it actually is (excluding the obnoxious syntax for certain things)

But yeah, JS has always been the crucial problem that needs to be solved. *.js is never going to solve it.

[pmarreck]

<opinion> OOP+FP is the wrong approach, and I'm putting that kindly. (This is also why I nixed Clojure, btw.) Having worked on large OO codebases, dependency hell, side effects, runaway state, and mutable data bugs (not to mention concurrency bugs) eventually become a serious problem, and out of the box, OOP does nothing to discourage these things (but functional languages do). As soon as you give developers access to "impurity" along with their "purity," you start earnestly down the path to massive technical debt. You could code the most functional Scala code ever, but as soon as you incorporate any library at all, you are right back to "zero concurrency guarantees" square 1.

What I'm getting at is that OOP+FP is, ultimately, simply OOP, providing none of the guarantees and encouraging none of the best practices that purely FP langs do. It's like the worst of both worlds lol

</opinion>

[premium-concern]

I develop in Scala and I honestly have never experienced the concerns you are raising.

"OOP" implies none of things you are worried about and Scala is a great example of that.

I wished people tried the language before making assumptions based on emotions that are not supported by reality.

[pmarreck]

What's the largest Scala codebase you've worked on, and what kinds of challenges have you run into?

[zura]

Does Scala.js also include similar "UI toolkit" as Elm? So no need to fall back to other frameworks.

[dsabanin]

Scala.js has react[1] which combined with diode[2] (influenced by elm) creates a powerful framework for developing new generation of web apps. There's also a GraphQL implementation called Sangria[3].

1. https://github.com/japgolly/scalajs-react

2. https://github.com/ochrons/diode

3. http://sangria-graphql.org