Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Official proposal for Type Unions in C#

github.com

Post reply on HN
Print view View original

11–20 of 315 posts

Re: Official proposal for Type Unions in C#

#11

Post by kriiuuu »

Eji1700 wrote: post #4
tombert wrote: post #3

Huh, I did F# for years with discriminated unions, and I guess I just assumed C# would have had them by now. I know not everyone likes them, but for typed languages I find it extremely hard to go back to languages without ADTs of some kind. I do Java for my current job, and Java is generally fine enough, but it's a little annoying when I have to do whacky workarounds with wrapper classes to get something that would b…

F# is so hard to walk back from. I wish Microsoft would support it better and actually push it, because it's such a perfect sweet spot. Most of the functional advantages without being shackled to pure functions and the like is so easy to develop in. Instead they've been, very slowly, turning C# into F#, which is even weirder to watch.

I feel the same about Scala. I use Scala3 daily and almost every other language is such a step back. I have looked at F# and it looks like one of the only other languages I would enjoy as much as Scala. Haskell is nice too, but the ecosystem is just not quite there. F# being able to tap into the rich C# ecosystem and Scala being able to tap into the Java ecosystem is such a win and makes them feel a lot less niche when you use them.

Re: Official proposal for Type Unions in C#

#12

Post by wk_end »

ComputerGuru wrote: post #8

Every time the question of preferred programming languages comes up, I'm usually in the extreme minority with my preferences being Rust (for small/fast) and C# (for productive and easy, where GC is acceptable), a combination that doesn't seem to appeal to too many people. But for the projects that fall right about in the middle where it could go either way and I could see either language working, I almost always pick…

Instead of C#, why not F#? You get proper ADTs among many other great features, but you still get all the utility of the .NET ecosystem.

Re: Official proposal for Type Unions in C#

#13

Post by orra »

Is the terminology slightly off? AIUI TypeScript has type unions.

But this looks like a discriminated union which I'd recognise from F# or Haskell. The distinction I'd draw is that for a DU there are named case constructors. Yes?

Re: Official proposal for Type Unions in C#

#14

Post by tombert »

kriiuuu wrote: post #11
Eji1700 wrote: post #4

Earlier quoted context omitted.

F# is so hard to walk back from. I wish Microsoft would support it better and actually push it, because it's such a perfect sweet spot. Most of the functional advantages without being shackled to pure functions and the like is so easy to develop in. Instead they've been, very slowly, turning C# into F#, which is even weirder to watch.

I feel the same about Scala. I use Scala3 daily and almost every other language is such a step back. I have looked at F# and it looks like one of the only other languages I would enjoy as much as Scala. Haskell is nice too, but the ecosystem is just not quite there. F# being able to tap into the rich C# ecosystem and Scala being able to tap into the Java ecosystem is such a win and makes them feel a lot less niche wh…

I do like Scala, and I haven't touched Scala3, but I've found it pretty unwieldy for actual use. It feels like I'm constantly fighting with the type system in a way that ends up being annoying an unpleasant.

To be clear, it's not like I'm new to functional languages and their type systems, I've been doing Haskell for forever, and I did F# for a multiple years, but Scala has never really clicked for me.

Personally, for doing JVM stuff, I'm a pretty die-hard Clojure advocate. I feel like it's easy for me to write Clojure in the way that I think, while still allowing me to mooch off the entire Java ecosystem, and if there are things that I don't like about the language it's really not that hard to macro in a new feature (though obviously this should be used sparingly).

I definitely recommend giving F# a try. I think it's an extremely underrated language.

Re: Official proposal for Type Unions in C#

#16

Post by wk_end »

orra wrote: post #13

Is the terminology slightly off? AIUI TypeScript has type unions. But this looks like a discriminated union which I'd recognise from F# or Haskell. The distinction I'd draw is that for a DU there are named case constructors. Yes?

TypeScript has "union types". This proposal refers to them as "ad hoc unions". I don't think "type union" is a term of the art - at least I haven't heard it before. It seems to be something the C# people are making up to describe sum types.

Re: Official proposal for Type Unions in C#

#17

Post by [deleted] »

ComputerGuru wrote: post #8

Every time the question of preferred programming languages comes up, I'm usually in the extreme minority with my preferences being Rust (for small/fast) and C# (for productive and easy, where GC is acceptable), a combination that doesn't seem to appeal to too many people. But for the projects that fall right about in the middle where it could go either way and I could see either language working, I almost always pick…

[deleted]

Re: Official proposal for Type Unions in C#

#20

Post by SideburnsOfDoom »

wackro wrote: post #18

What would the rough timeframe be for seeing adoption of this into the language? I was considering introducing the OneOf library into our codebase, but if this is < a year or so away it might not be worth the effort.

The linked says "Proposed, Prototype: Not Started, Implementation: Not Started, Specification: Not Started"

.NET releases are every November, and I would be very surprised to see this in November 2024. More likely November 2025 at soonest. But check back to that page later.

Post reply on HN