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Official proposal for Type Unions in C#

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Re: Official proposal for Type Unions in C#

#31

Post by electroly »

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'm glad they're simply turning C# into F#. They're coming to us where we are, rather than forcing us to make a jump. I'm a relatively "blue collar" developer, I know a little about FP (not enough to be productive in F#) but I have tons of C# experience. I appreciate them taking the good stuff from F# and making it understandable to C# developers. It's been a delightful progression; no big jumps, no paradigm shifts, just the steady addition of useful new features that I can understand.

Re: Official proposal for Type Unions in C#

#32

Post by ctenb »

I find it strange and slightly confusing that tey call it "union types". The correct term would be "sum types" or "discriminated union types", union types being the union of two types with no distinctive tag between the two cases. E.g. |Int ∪ Int| ≡ |Int|, while |Int + Int| ≡ 2 |Int|

Re: Official proposal for Type Unions in C#

#33

Post by lp0_on_fire »

wk_end wrote: post #12
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.

Nothing against F# but the developer ecosystem around C# is just plain better, especially if you're already a dotnet shop. Documentation, code examples, tooling, developers who already know the language, etc.

F# doesn't really buy you anything if you're already invested in C# (or even VB.net for those poor souls) unless you have a very specific use-case for it, IMO.

Re: Official proposal for Type Unions in C#

#34

Post by ctenb »

I'm currently using nested records with a private constructor in combination with the nuget package https://github.com/shuebner/ClosedTypeHierarchyDiagnosticSup... to make sure the switch types do not require a `_` case. This is essentially the desugared version of their "Union Classes" proposal. This already works very well. Still, I like this proposal because it would be nice if the nuget package would become unnecessary and the syntactic sugar is also nice to have.

Re: Official proposal for Type Unions in C#

#35

Post by kldx »

mlinhares wrote: post #22
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…

C# is great, likely the best mainstream programming language nowadays, but its in the hands of microsoft and microsoft didn't really care much about building a community or getting it to work natively in other OSes/toolchains. Its a shame, they even had a second change when Oracle bought sun and no one knew what was going to happen with Java, but fumbled that as well.

https://isdotnetopen.com/

Re: Official proposal for Type Unions in C#

#36

Post by mlinhares »

DaiPlusPlus wrote: post #28
mlinhares wrote: post #22

Earlier quoted context omitted.

C# is great, likely the best mainstream programming language nowadays, but its in the hands of microsoft and microsoft didn't really care much about building a community or getting it to work natively in other OSes/toolchains. Its a shame, they even had a second change when Oracle bought sun and no one knew what was going to happen with Java, but fumbled that as well.

> but its in the hands of microsoft and microsoft didn't really care much about building a community or getting it to work natively in other OSes/toolchains. That statement was true - until 2016. Times change, Microsoft changed.

Nah, people continue to pick Java or Go when they want to build their enterprise systems if they're not already married to Microsoft.

There's not a single widely distributed infra application in C# out there. When people want to build stuff like kafkas, kubernetes, consuls, they still go to Java/Go/C++.

Re: Official proposal for Type Unions in C#

#37

Post by [deleted] »

mlinhares wrote: post #22
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…

C# is great, likely the best mainstream programming language nowadays, but its in the hands of microsoft and microsoft didn't really care much about building a community or getting it to work natively in other OSes/toolchains. Its a shame, they even had a second change when Oracle bought sun and no one knew what was going to happen with Java, but fumbled that as well.

[deleted]

Re: Official proposal for Type Unions in C#

#38

Post by antonyt »

fluoridation wrote: post #21
wk_end wrote: post #12

Earlier quoted context omitted.

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.

I get the feeling F# is a second-class citizen in the ecosystem. How likely is it (or is it at all possible) that I'm going to run into some library that doesn't work with F#?

It's impossible for a .NET library to not work with F#. It's very possible (and even likely) for a .NET library to prevent you from writing idiomatic F#.

You're right that it's a second-class citizen.

Re: Official proposal for Type Unions in C#

#39

Post by giancarlostoro »

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…

For me its C# and Python, though I like Rust, D and lately been getting into Nim. I want to like Lisp, but its just not something I see someone paying me to work in.

Re: Official proposal for Type Unions in C#

#40

Post by owisd »

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.

It's a different kind of ugly, but you can use the Visitor pattern to get the same exhaustiveness checking at compile time without a library.
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