Comment by louthy | Hacker News Reader

Comment by louthy | Hacker News Reader

Parent Full thread

That is until Microsoft release a version of the Framework or a version of VS that breaks F# in your project. I dropped F# support from my one of open-source projects because of this, and at my company we've decided to stop all future F# development. The move to .NET Core was an absolute clusterfuck for F# ... well, it was for C# too, but everything broke in the F# world ... I even ended up on a Skype call with the PM of the F# team as he tried to help resolve my issues; it's amazing he was willing to help, but it was kind of indicative of a bigger issue (I believe).

The tooling is poor in general, the interop is questionable at best. One example is `Option a` in F# becomes `FSharpOption<A>` in C#, with `None` being `null` - breaking all of the type-safety of the union-type. It isn't seamless in the way some might have you believe. The standard answer is build a wrapper to expose F# to C#, which is ok, but is an extra level of indirection and complexity that shouldn't be needed (if indeed the idea is to have seamless interop).

I developed language-ext [1] to bridge the divide, but in the end there isn't a strong enough reason to write F# all the time in the .NET sphere. It is compromised by an ecosystem where C# is dominant. That includes the framework libraries and even the limitations of the type-system in F# (no higher kinds for example). There's no real reason for F#, other than a nicer syntax, it doesn't have a killer USP like Haskell (purity) or Erlang (concurrency).

If it wasn't in C#'s shadow, and it was able to run free, and without compromise, there could be a compelling narrative - but what we're doing now is moving to PureScript for our front-end, and Haskell for microservices where we need the USP of Haskell (purity and strict domain modelling).

[1] https://github.com/louthy/language-ext/

There is barely any reason for FSharp to exist if not for dotnet interop(from the fsharp history paper). There are some novelties but they came later.

Any language developed on dotnet platform will always be in C#'s shadow. F# is much nicer to write than C#(for now), if you need to develop on dotnet.

I want a statically typed functional language with a big ecosystem. I want to use the same language across front-end and back-end.

What are my options?

- PureScript on web and Node.js

Can use NPM packages! Node.js as a run-time lacks features like shared memory across threads. PureScript is still too early IMO.

- Scala on JVM and web using Scala.js

Not a bad option, although the language is very complex. More towards the OOP end than the ML end in the spectrum of language design. JVM can be a good or a bad thing, depending on what you are doing.

- F# on .NET Core and web using Fable

Simple functional language with access to the .NET ecosystem. ASP.NET has great performance. Access to NPM packages on web. Lacks some advanced type-system features in Haskell, OCaml and Scala. However, the community has a pragmatic focus as a result.

- OCaml and ReasonML

ReasonML has limited backing from Facebook. OCaml has support from a few financial institutions (e.g. Jane Street) but it's not on the same level as what a big tech company could provide. Tiny (but high quality) community and ecosystem. OCaml has great single-threaded performance but mult-threading is not quite ready. Already small community split by compiler extensions and standard libraries.

- Haskell and GHCJS

Again, tiny community and ecosystem. Beautiful language, but lazy evaluation has bit me too many times. Steep learning curve since newcomers cannot fall-back to OOP and imperative code.

- Elm

Tiny ecosystem, tied to Node.js (see PureScript). Interop story with NPM modules is worse than PureScript.

For me, F# is the clear winner.

If you aren't particularly interested in functional programming - maybe you just use some delegates here and there - then C# is a fine choice. Otherwise, C# quickly becomes awkward compared to F#. Besides, C# to JS options are not as mature as Fable.

Also Clojure/ClojureScript if you're willing to give up the static typing.

Clojurescript with Re-Frame / RE-Frame-10x / Reagent has transformed front-end for me. It's so good.

Re-frame (just like Clojure in general) seems to be much more stable than alternatives in a sense how much things change over time.

Clojure is such a different school of thought! Most of the arguments I have heard for Clojure (immutability, thinking in data, etc) also apply to ML though. Still, I hope to try it out properly one day!

I wonder what is easier for a strong OOP developer to learn, Lisp or ML?

Lisp and Clojure have CLOS, which is more powerful than what most people know as OOP.

ML, depending on the flavour gets pretty how one combines functors, aka generic modules, which is similar to component based programming like COM, or just plain objects as in OCaml.

Now the immutability isn't as hard to adapt to as one may think.

Clojure has CLOS? That would be new.

Fair enough, I was over simplifying, still it has a nice subset of it.

What is this 'subset'? CLOS is based around class&inhertance&mutability + generic function dispatch over classes. Spiritually Clojure wants to avoid OOP, where CLOS is a full object system with an optional meta-layer.

I know you are a Lisp expert with a deep knowledge of its eco-system, but trying to downplay the existence of multiple dispatch and protocols doesn't help.

Also I bet that The Art of Metaobject Protocol reference implementation can be ported into Clojure without major issues.

The Art of the Metaobject Protocol has no 'protocol reference implementation'. Neither CLOS nor AMOP supports explicit protocols. Explicit protocols are a feature of Clojure.

https://clojuredocs.org/clojure.core/defprotocol

"A protocol is a named set of named methods and their signatures"

Such protocols are not a language feature of CLOS.

AMOP describes a 'Metaobject Protocol' (MOP) and has a tiny example implementation (called Closette). This is entirely different from what the 'protocols' feature does in Clojure. A 'protocol' in AMOP is informal.

What AMOP actually describes with its MOP, is a meta-level of meta-classes and generic functions, which implement large parts of CLOS itself. Such the classes, generic functions, methods, slot descriptors, etc. are CLOS objects themselves.

Clojure supports a form of multiple dispatch, but the dispatch mechanism is also very different from CLOS - for example it uses a dispatch method per generic function, selects one method and has no idea of a next method. CLOS for example uses a built-in dispatch mechanism, multiple class-based dispatch hierarchies for multiple arguments, using a set of methods which are selected based on the class hierarchy.

https://clojure.org/about/runtime_polymorphism

Typically it is not a good idea if Clojure uses a name for a feature, to generally think that this is similar to a feature with a similar name in Common Lisp -> 'protocols' and 'meta-object protocol' are two very different things.

Porting the CLOS MOP to Clojure would be possible, when one first implements CLOS in Clojure. Otherwise it makes very little sense, since Clojure does not by default support the (older) view of object-oriented programming of CLOS. Something which the Clojure designer thought of a feature: getting rid of things like mutable objects, class based inheritance, class-based OO, etc.

The interop story really needs to be fixed quickly. There will always be some rough edges but things like basic collections (Sequences, Lists, Arrays, ImmutableArray, Option...) and high performance things (Tuples, Tasks, including ValueTuple and ValueTask) must just be fluent across the languages even if it means backwards compatibility is broken or the types work less than ideally on both sides of the fence.

I mean it works for my cases. We interop mostly small libraries where we need/prefer a better functional shell. I guess those rough edges start kicking on larger code base.

The move to core was messy, but I am personally glad they did it just for the better linux support.

Great library by the way thanks for making it!

The move to .NET Core broke everything. PowerShell is still broken, with fundamental issues that may remain unresolved for a long time. I don't expect most people to switch over until PS v9.0 at the earliest.

What part of Powershell is broken? Are you referring to module compatibility or other issues?

For my shop, the AD module was an obstacle until v7. Many Azure-related modules still seem to be 5.1 only.

The module compatibility thing isn't just developers being lazy and not porting over their modules, it's actually a fundamental thing to do with the way .NET Core was architected.

Because -- you know -- in the 2020s there are only web apps and mobile apps. There are no other types of "applications". That unnecessarily long word only exists in dead tree dictionaries like Oxford, and is used by old people that still cling to their "personal computers" of yesteryear. So of course, .NET Core was made only for web apps, with a hint that mobile apps might one day work also. Microsoft will say otherwise, of course, but in practice 100% of the decisions were to ship an MVP that can be used to create a web application. All the doco was for web apps. All of the samples were for web apps. Whenever there was a decision to be made, they made it with web apps in mind.

This has made some things impossible, especially related to actually loading dynamic link libraries (DLLs) dynamically, which despite the "dynamic" in the name is surprisingly problematic in .NET Core.

It really wants you to ship a monolithic, statically linked app. Anything else is just a nightmare of compatibility shims and flags that ought to be at the DLL level but are actually set (once only) at the EXE-level.

This makes PowerShell Core modules very sensitive to the exact version of .NET Core used to compile PowerShell itself, contrary to how the old PowerShell used to work, where you could upgrade the system framework to enable the loading of a newer module built against that framework.

Similarly, if there is another module that pulls in something with compatibility shims (or not), then that can break your module in weird and wonderful ways.

I tried to write a .NET Core module for PowerShell core several times, and every time I got bogged down in reams of inscrutable internal framework errors that had 2-3 hits maximum in Google, all from other people complaining about PowerShell development having being broken.

Reply on news.ycombinator.com