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Union types in C# 15

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Re: Union types in C# 15

#91

Post by merb »

tialaramex wrote: post #75

I don't love OneOrMore It's trying to generalize - we might have exactly one T, fine, or a collection of T, and that's more T... except no, the collection might be zero of them, not at least one and so our type is really "OneOrMoreOrNone" and wow, that's just maybe some T.

OneOrMore is more or less an example from the functional world. i.e.:

https://hackage.haskell.org/package/oneormore or scala: https://typelevel.org/cats/datatypes/nel.html

it's for type purists, because sometimes you want the first element of the list but if you do that you will get T? which is stupid if you know that the list always holds an element, because now you need to have an unnecessary assertion to "fix" the type.

Re: Union types in C# 15

#92

Post by algorithmsRcool »

celeries wrote: post #59
mwkaufma wrote: post #51

Looks like it's "just" type-erasure / syntactical sugar. E.g. value types are boxed.

Yes, but that's just the default behavior. You can implement your own non-boxing version for performance critical applications.

Why on earth did they decide boxing by default was a sensible design decision...

We have been pushing toward higher performance for years and this is a performance pitfall for unions would are often thought of as being lighter weight than inheritance hierarchies.

F# just stores a field-per-case, with the optimization that cases with the same type are unified which is still type safe.

Re: Union types in C# 15

#93

Post by jayd16 »

FrustratedMonky wrote: post #11

Is this the last of the F# features to be migrated into C#? What a missed opportunity. I think really F# if you combine all of its features, and what it left out, was the way. Pulling them all into C# just makes C# seem like a big bag of stuff, with no direction. F#'s features, and also what it did not included, gave it a style and 'terseness', that still can't really be done in C#. I don't really get it. Was a funct…

Purity is overrated. C# is a kitchen sink language but you need give credit to the language designers. Compared to C++, for example, C# feels feature rich and consistent even though it abandons purity.

Re: Union types in C# 15

#94

Post by wvenable »

owlstuffing wrote: post #52
LunicLynx wrote: post #23

Earlier quoted context omitted.

You aren’t giving enough credit to the careful evaluation of how this adaption is happening. So far everything that was added to C# very much reduces the amount of dead boilerplate code other languages struggle with. Really give it an honest try before you judge it based on the summation of headlines.

In isolation, yes, I agree with you. But in the context of the cornucopia of other "carefully evaluated" features mixed into the melting pot, C# is a nightmare of language identities - a jack of all trades, master of none, choose your dialect language. No thanks.

> C# is a nightmare of language identities - a jack of all trades, master of none, choose your dialect language.

I honestly have no idea where you would get this idea from. C# is a pretty opinionated language and it's worst faults all come from version 1.0 where it was mostly a clone of Java. They've been very carefully undoing that for years now.

It's a far more comfortable and strict language now than before.

Re: Union types in C# 15

#95

Post by delta_p_delta_x »

gib444 wrote: post #21

Is C# a great language trapped in a terrible ecosystem? ie would masses use C# if it existed in another ecosystem? Or is it becoming a ball-of-mud/bad language compared to its contemporaries? (Honest questions. I have never used .NET much. I'm curious)

> terrible ecosystem

.NET is a fantastic ecosystem. Has a decent build and dependency system (NuGet, dotnet run/build, declarative builds in XML). Massive standard library, with a consistent and wide focus on correctness, ergonomics, and performance across the board.

You can write everything in many languages, all on the same runtime: business logic in C#; hot paths interfacing with native libraries in C++/CLI; shell wrappers in PowerShell, document attachments with VB, data pipelines in F#.

I feel more people should use it, or at least try it, but sadly it is saddled with the perception that it is Windows-only, which hasn't been true for a decade (also, IMO, not necessarily a negative, because Windows is a decent OS, sue me).

Re: Union types in C# 15

#96

Post by wvenable »

raincole wrote: post #24
FrustratedMonky wrote: post #11

Is this the last of the F# features to be migrated into C#? What a missed opportunity. I think really F# if you combine all of its features, and what it left out, was the way. Pulling them all into C# just makes C# seem like a big bag of stuff, with no direction. F#'s features, and also what it did not included, gave it a style and 'terseness', that still can't really be done in C#. I don't really get it. Was a funct…

Union is almost a net positive to C# in my opinion. But I do agree. C# is heading to a weird place. At first glance C# looks like a very explicit language, but then you have all the hidden magical tricks: you can't even tell if a (x) => x will be a Func or Expression[0], or if a $"{x}"[1] will actually be evaluated, without looking at the callee's signature. [0]: https://learn.microsoft.com/en-us/dotnet/csharp/advanc…

> you can't even tell if...

In the places where that is a thing, I've never needed to care. (Which is kind of the point)

Re: Union types in C# 15

#97

Post by jayd16 »

NanoCoaster wrote: post #20
FrustratedMonky wrote: post #11

Is this the last of the F# features to be migrated into C#? What a missed opportunity. I think really F# if you combine all of its features, and what it left out, was the way. Pulling them all into C# just makes C# seem like a big bag of stuff, with no direction. F#'s features, and also what it did not included, gave it a style and 'terseness', that still can't really be done in C#. I don't really get it. Was a funct…

Absolutely agree. Modern C# language design feels very much lacking in vision or direction. It's mostly a bunch of shiny-looking language features being bolted on, all in ways that make the language massively more complex. Just look at this feature: https://learn.microsoft.com/en-us/dotnet/csharp/whats-new/cs... Was this needed? Was this necessary ? It's reusing an existing keyword, fine. It's not hard to understand.…

> Try teaching someone C# nowadays

Do you actually have a datapoint of someone failing to understand C# or are you just hyperbolically saying its a big language? The tooling, the ecosystem, the linting, the frameworks. Its a very easy language to get into...

Re: Union types in C# 15

#98

Post by jayd16 »

gib444 wrote: post #21

Is C# a great language trapped in a terrible ecosystem? ie would masses use C# if it existed in another ecosystem? Or is it becoming a ball-of-mud/bad language compared to its contemporaries? (Honest questions. I have never used .NET much. I'm curious)

Its a great language in a very good ecosystem. Try it. Its great.

It has a bad rep because Microsoft could Microsoft as they do.

Re: Union types in C# 15

#99

Post by FrustratedMonky »

jayd16 wrote: post #93
FrustratedMonky wrote: post #11

Is this the last of the F# features to be migrated into C#? What a missed opportunity. I think really F# if you combine all of its features, and what it left out, was the way. Pulling them all into C# just makes C# seem like a big bag of stuff, with no direction. F#'s features, and also what it did not included, gave it a style and 'terseness', that still can't really be done in C#. I don't really get it. Was a funct…

Purity is overrated. C# is a kitchen sink language but you need give credit to the language designers. Compared to C++, for example, C# feels feature rich and consistent even though it abandons purity.

I think purity matters where you can have the compiler catch problems.

Re: Union types in C# 15

#100

Post by jayd16 »

gib444 wrote: post #31
JCTheDenthog wrote: post #22

Earlier quoted context omitted.

Depends on what you mean by ecosystem, it hasn't been trapped on Windows for about a decade now. The variety of third party libraries available is quite good, while the standard library is robust enough that you don't need NPM nonsense like LeftPad and IsEven and IsNumber. Are there particular things about the ecosystem that you worry about (or have heard about)? Biggest complaint I would have is that it seems like m…

Yup, the commercial libraries. That's pretty big. It's nice the standard library has lots of goodies, but I doubt many projects in reality are zero-dependency (The amount of times I hear "the standard lib is great!" seems more to attempt to defend the plethora of commercial libraries, more than anything) The community feels rather insular too? The 9-5 dayjob types with employers who don't understand or embrace open s…

The anemic open source projects are really from the lack of good cross platform support early on. That's changed now but it missed out on a time of rapid OSS expansion that Java and other took in.

It is what it is but I wouldn't say its actually the fault of the language, especially now.

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