https://medium.com/@eeue56/why-type-classes-arent-important-...
"Right now, any Elm developer can examine Elm code that another developer has written, and fully understand what is going on. I consider this a major thing that Elm has got right."
And
"Elm is targeted at the main source of users it has — Javascript developers. Javascript developers may be familiar with typeclasses, but it is less likely that they are than Haskell developers. Alternatives like Purescript provide more abstractions and powerful type systems suited to those from the Haskell community. There are many of us Haskell users who sit happily with Elm too."
Elm favors simplicity and pragmatism over academic FP lingo. You need to change your way of thinking a bit, true, but it benefits the architecture. And it'll take weeks, not years!
You will not find the words "monad" or "category theory" or "algebraic datatype" used in the Elm docs.
I would recommend Typescript then.
> Frankly, I am not sure why is functional paradigm considered a savior and better approach for inherently non-concurrent web frontend technology.
True, FP excels at concurrent programming, but that's far from its only strong point. I'd propose that React-like architectures (which are based around a pure Model -> View function) and functional languages are a match made in heaven.
Funny, all people using Typescript I know use it in functional way (computer vision/AR in a browser).
Scala and ML-variants like Ocaml, F#, Reason.js are perfectly good imperative languages. They don't force you to go purely functional. I always recommend that my students (whose first language is Java) start by treating Scala as a "nicer Java", and then slowly explore Scala's more powerful features. Indeed, I'd argue that Scala and the aforementioned ML-variants are (slightly) better general-purpose imperative languages than the Javas, Pythons, PHPs and Javascripts of this world, because they are more consistent, they have types/type-inference, and their statefulness fully supports higher-order state and powerful modularisation without restriction, not to mention pattern matching.
Being able to use functional idioms without compromise if and when desired (including, but not restricted to, pure functional programming) is another benefit of Scala and ML-variants.
The biggest problem of very functional code on the web is simply debugging it. So much control flow is buried in compositions that there isn’t much to grab on in terms of break points or variable inspection. Pure languages exacerbate this problem by making state more difficult to dig out and pin down at run-time.
I don't see why that's a problem with FP and not just the lack of tooling in most FP languages. Debugging in F# via Visual Studio is a breeze, and OCaml's time travelling debugger looks pretty good.
do
x <- newIORef 0
writeIORef x 2
print =<< readIORef x
[0] https://en.wikipedia.org/wiki/Software_transactional_memory
The notion of monad comes from category theory [...] It first arose in the area of homological algebra, but later was recognised (due to the work of Kleisli and of Eilenberg and Moore) to have much wider applications. Its importance emerged slowly: in early days, it was not even given a proper name, but called simply a "standard construction" or a "triple" [...] Eugenio Moggi proposed that monads provide a useful structuring tool for denotational semantics [...] He showed how lambda calculus could be given call-by-value and call-by-name semantics in an arbitrary monad, and how monads could encapsulate a wide variety of programming language features such as state, exception handling, and continuations. Independent of Moggi, but at about the same time, Michael Spivey proposed that monads provide a useful structuring tool for exception handling in pure functional languages, and demonstrated this thesis with an elegant program for term rewriting [...]. He showed how monads could treat exceptions [...] and non-deterministic choice [...] in a common framework.
[1] P. Wadler, The essence of functional programming.
I've been learning Elixir (a functional language) for a new project I'm working on and even with only being able to allocate 20-30 minutes a day on it, I don't feel like I need to relearn everything. This is with no prior functional language experience, just a bunch of general experience with Python and Ruby.
I have no formal CS education and while I've heard the terms category theory and monads before I have no idea what they are. In my mind, monads are some Haskell related meme and category theory is thinking about whether or not to use categories on a blog engine.
I found Elixir to be curiously easy to adapt to. I spent like 15 minutes glancing Elixir's documentation and now I'm running a Phoenix based web app (somewhat comparable to Rails but not really) following an "error based development" work flow.
This is where you try to do something, completely fail at it, look up the answer and figure out how to apply it. I don't even know how most of Elixir / Phoenix works yet I'm able to accomplish real things.
After spending 15 minutes reading Phoenix's docs on routing, I actually feel like I understand Phoenix's routing system better than other frameworks in different languages that I've worked with for years. This is partly because it's so easy to just trace a function call back to another function call and understand what's going on (plus their docs are badass).
...which targets JavaScript in addition to the JVM (and being an officially supported language for Android development): https://kotlinlang.org/docs/reference/js-overview.html
I ended up going with vue which uses mutations instead of having to return structure copied from functions.
Just made more sense to me. Maybe MobX does this for react? Idk
Not everybody wants to spend next 5 years learning thinking bottom-up, mastering category theory, monads and all that for such a task like writing a silly webpage you wouldn't rather be doing.
[rant] Frankly, I am not sure why is functional paradigm considered a savior and better approach for inherently non-concurrent web frontend technology. I program in Haskell/Scala but pushing functional programming everywhere is IMO just insanity and everybody is silent about many warts and weirdness of purely functional programming. [/rant]