The history of C# and TypeScript with Anders Hejlsberg [video] | Hacker News Reader

The history of C# and TypeScript with Anders Hejlsberg [video]

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199 pointsdoppp156 comments

I started my career doing ~20 years of C# from pretty much the very beginning (JavaScript even before then!).

Around 2020, I switched into the startup space and quickly picked up TypeScript since that's "what the kids use". It wasn't without struggles, but once I wrapped my head around TypeScript as "shapes for JavaScript", it clicked.

At the time, the startup was undertaking a new product built on Nest.js[0] which looked awfully similar to ASP.NET web APIs which had the benefit of being much more mature, complete, and with one of the best ORMs (EF Core). I suggested it to the team and was a bit shocked by the pushback.

It ultimately inspired me to do a bunch of writing [1][2] on just how similar these two languages are and how they've converged on syntax (no doubt owing to Anders at the helm). Of course, they ultimately still have quite a bit of a gap, but for teams that are working in TS and finding that they are outgrowing it, C# is a very natural choice.

I left that startup after a short stint, but boomeranged almost 3 years later. Company went from seed to series C in that time. End of last year, we started the migration from TypeScript on the backend to C# on the backend and haven't looked back. The toolchain is far simpler and stable, the "default" ORM is far more flexible and powerful, the more rigorous type chain seems more conducive for agent-driven coding. Team adapted relatively quickly within ~4 weeks.

[0] https://nestjs.com/

[1] https://typescript-is-like-csharp.chrlschn.dev/

[2] https://itnext.io/getting-functional-with-c-6c74bf279616

I can't say for sure because I don't know the full situation, but I've heard a similar story a few times and IMNSHO looking at it as "they made the wrong choice initially" is off because it assumes that a C# team could have delivered the initial version in the timeline required to get to the the next level of project.

If they had a team that knows nest and can iterate fast with it that's the perfect choice. I've worked at multiple agencies over the years and was mostly in C# teams. Whenever a C# team got on greenfield/startup projects it ended up being a shit-show of self inflicted slowdowns/over-complications. I've seen 3 projects where in large part due to slow development of the MVP the project missed investment window or ran out of funds.

From my experience Node/Rails teams were much more capable of delivering shit that works. It would eventually have a bunch of problems that would be non issues by default on a different stack like ASP.NET, but the difficulty of getting to that point and realizing that just being in that situation is a win is what most engineers miss.

Same experience here. C# might have superior tooling, performance, whatever but the OOP baggage is too heavy. In theory you can write something else than a giant over-complicated, over-abstracted pile of OOP nonsense in C#, but every team I've seen has.

Just to keep it relevant and off topic. Typescript is moving to go because you just cannot get performance out of javascript because of its design.

As he says in the video about perf "you cannot leave 10x on the table".

> Typescript is moving to go because you just cannot get performance out of javascript because of its design.

That's not an accurate summary. An accurate summary is that:

- They can't get the performance they want out of V8

- They're are moving to Go because its design is similar enough to JS that they can do a line-by-line port

These aren't similar claims (or mere quibbling) compared to what you wrote. They're very nearly exact opposites.

You can write very functional C#. Our codebase is a mix with some aspects being functional (`ErrorOr`[0] being a big part of it as well as `OneOf`[1]) and OOP. Our core, common services all return `ErrorOr` to allow fluent call chaining at the top of the stack (controllers).

Modern C# features like `switch` expressions[2] (not `switch-case`) and pattern matching mean that it is possible to write very terse, expressive code. Extension members and methods[3] go a long way as well by making the builder pattern easier to implement.

Overall, it's up to the team to make use of the tools provided by the C# team. You can write C# in a very OOP heavy way (as is possible with TS in the case of Nest.js); you can also write in in a very functional way given many of the functional features adopted from F# over the years. It's up to the team.

[0] https://github.com/amantinband/error-or

[1] https://github.com/mcintyre321/OneOf

[2] https://timdeschryver.dev/blog/pattern-matching-examples-in-...

[3] https://typescript-is-like-csharp.chrlschn.dev/pages/interme...

That's a perfect example of making it overcomplicated, just in the FP direction.

C# uses exceptions for error handling. It has it's own control flow primitives. C# developers know how to work with it, everything else uses it. Why would I want to pull in a randos GH DSL and types to pretend I'm writing F# when I can just use F# that has first class support for this ?

C# is already very functional when it comes to Linq. In real world use, this just feels like extending in the same directionality while still preserving familiarity. Whereas F# does feel like an entirely different language.

Learning C# when you know TS is like learning Portuguese when you know Spanish.

> In theory you can write something else than a giant over-complicated, over-abstracted pile of OOP nonsense in C#, but every team I've seen has.

C# syntax is fine, but has a rotten[1] culture/conventions. I suppose it makes sense that Microsoft's "Java-killer" became enterprise-y, with the same over-engineered indirections.

1. IMO - I find it very unpleasant and never allowed myself to Internalize the IConventions out of spite. YMMV.

    > ...because it assumes that a C# team could have delivered the initial version in the timeline required to get to the the next level of project.

I linked the Nest.js project because you can see how similar these two are[0] with Nest.js leaning into the OOP aspects of TS at the very core. Controllers and services are classes in Nest.js, for example. It uses a somehow more complicated DI system than ASP.NET. It is Spring Boot or ASP.NET, but without the maturity, performance, and ergonomics.

The team had developers that had done C# before and later hires also included former C# developers.

TS itself was new for the team at the time and several mistakes were made along the way resulting in a "dual-ORM" situation (Prisma + Drizzle; both with their faults) that ends up sapping a lot of productivity (one of the drivers to move to C#).

[0] https://typescript-is-like-csharp.chrlschn.dev/pages/interme...

Hmmm. I have a different take there: when you are young and wild, you achieve stuff because you think later and instantly produce code. When you turn older, you do it the other way leading to your example.

In the early 2000s I have been in a startup and we delivered rapidly in C# as we did in PHP. We just coded the shit.

I think what you said is a healthy progression : write dumb code -> figure out it doesn't scale -> add a bunch of clever abstraction layers -> realize you fucked yourself when you're on call for 12 hours trying to fix a mess for a critical issue over the weekend x how many time it takes you to get it -> write dumb code and only abstract when necessary.

Problem is devs these days start from step two because we're teaching that in all sources - they never learned why it's done by doing step one - it's all theoretical example and dogma. Or they are solving problems from Google/Microsoft/etc. scale and they are a 5 people startup. But everyone wants to apply "lessons learned" by big tech.

And all this advice is usually coming from very questionable sources - tech influencers and book authors. People who spend more time talking about code than reading/writing it, and earn money by selling you on an idea. I remember opening uncle bobs repo once when I was learning clojure - the most unreadable scattered codebase I've seen in the language. I would never want to work with that guy - yet Clean Code was a staple for years. DDD preachers, Event driven gurus.

C# is the community where I've noticed this the most.

I assume the startup wasn't also leveraging typescript heavily on the frontend, that tends to shift the weight in its favor. Having one set of tools to use across everything, being able to share logic and types without needing to go through lossy translation layers, and giving (especially small) teams better flexibility to move people around is a huge benefit.

We are using TS on the FE with React.

But the reality is that at some point, your FE and BE teams will diverge anyways and we use an OpenAPI spec as the contract (Nest.js, not Next.js).

So there was no benefit to using TS on both ends; only pain on the BE.

If a team is going to ship an OpenAPI spec and run it through a transformer, then it changes the selection criteria for a BE language:

    - Easy for a TS team to adopt; similar core semantics like `async/await`, exception handling, etc.
    - Flexible and pluggable OpenAPI spec generation for edge cases and advanced scenarios
    - Excellent ORM to improve productivity around CRUD
    - Good tooling
    - Extensive docs, platform maturity, but modern language features

C# meets all of those in ways that no other language and platform does.

I can't speak to your use case, but for past projects I've not only wanted to share types but actual logic. For instance, if you want instantaneous validation on the frontend, while applying the same logic on the backend with submitted data. In many instances that would be simple and maybe even serializable, but in my case I was working with architectural data that had extremely detailed logic for what was and was not valid.

Using a TS validation library like Zod gives you both the shared validation code for both the frontend and backend, the TS types, as well as the json schema for openapi. It's a triple whammy too good to ignore. Especially as a small team it is huge leverage enabling you to go further faster.

That's simple; check out https://Orval.dev or https://Kubb.dev. Both of which can generate validation code (among other things) from OpenAPI.

Example with .NET: https://github.com/CharlieDigital/dn-kubb

> the "default" ORM is far more flexible and powerful

I have never used any ORM that is as capable. Entity Framework Core with Linq is what keeps me on .NET.

Because EF's default behavior implements Unit of Work, a LOT of the complex transactional spaghetti ended up disappearing when we switched.

This aspect of EF is highly underrated for complex entity graph mutations.

EF makes the 90% use case easy and the 10% case possible with very little pain. The interceptors, global conventions, and other extension points are an enabler of complex behaviors that are still transparent to most of the team.

> Because EF's default behavior implements Unit of Work, a LOT of the complex transactional spaghetti ended up disappearing when we switched.

I have never felt more understood by a fellow HN user. I think I know the exact spaghetti you are talking about, and I agree with you 100%. I wish EF could create (SQL) views, but it's not really any issue considering I can just use raw SQL to accomplish the same thing.

> complex entity graph mutations.

I'm too dumb to know what those words mean together. But I going to assume it's something to do with complex entities. If so, I completely agree as well. I sometimes harness the powers of the Dark Magics where my domain entities and database entities are the same objects (I'm not one of those DDD people either). Thanks to EF, I've been able to create some complex objects that really have cut down on a lot of useless objects I used to litter applications with.

Surprising to me that (in the context of TypeScript) ECMAScript 4, ActionScript, and Google Closure were not mentioned! Especially the first two; Macromedia/Adobe and Netscape/Mozilla have been working on baking TypeScript into JavaScript proper for a whole decade before HTML5, the mobile boom, and the associated problems have emerged. ES4/AS3 even had a nearly identical syntax.

What's even more interesting is that Microsoft and Google were part of TC-39 at the time, and were the main opponents of ES4. While they had some rightful reasons to take this position, there's no way ES4 hasn't shaped TS in the end. Perhaps the lack of mention of any of this is due to that TypeScript might have been handed to Anders' team after the project vision and original design have developed (in the video, it is introduced as a continuation of "SharpScript"), but the interview still left me rather insatiated.

Out of the big 4 involved in typescript, only one was involved with the tc39

> ES4/AS3 even had a nearly identical syntax.

Yeah. As someone who lived that era it was so frustrating that they abandoned ES4. I used AS3 daily for almost a decade until Adobe abandoned ActionScript4 and Flash Next around 2015.

I worked on a web app that used AS3 and Adobe Flex for UI. It’s crazy to think about how powerful that framework was and it was twenty years ago now.

No, it was never right for public facing web sites but it shined making internal admins. HTML5 still hasn’t matched it.

EDIT: turns out Flex still lives on as Apache Royale: https://royale.apache.org/ wish I had an excuse to take it for a spin.

I watched this last week.

The part about veering constantly to navigate the maze of internal politics is fascinating. The compromises he had to make, like not being able to put in on Github initially. The easy victories, like making TypeScript open source.

The long road to success. The obligatory advice for people writing new programming languages (Hint: Mostly, don't.). His opinion about creating a new language for AI (I agree with his insight, but still think it is possible).

Overall, well worth watching.

I don't know that many languages but, having been writing lots of typescript in the last 3 years there are so many things I love about it.

It infers types. If I do

    const data = [
      { name: 'bob', age: 35, state: 'CA' },
      { name: 'jill', age: 37, state: 'MA' },
      { name: 'sam', age: 23, state: 'NY' },
    ];

Typescript knows data is an array of { name: string, age: number, state: string }. I don't have to tell it.

Further, if I use any field, example

    const avg = data.reduce((acc, { age }) => acc + age, 0) / data.length;

It knows that `age` is a number. If I go change data and add an age that is not a number it will complain immediately. I didn't have to first define a type for data, it inferred it in a helpful way.

Further, if I add `as const` at the end of data, then it will know 'state' can only be one of `CA`, `MA`, `NY` and complain if I try to check it against any other value. Maybe in this case 'state' was a bad choice of example but there are plenty of cases where this has been super useful both for type safety and for code completion.

There's insane levels of depth you can build with this.

Another simple example

    const kColors = {
      red: '#FF0000',
      green: '#00FF00',
      blue: '#0000FF',
    } as const;

    function keysOf<T extends string>(obj: { [k in T]?: unknown }): readonly T[] {
      return Object.keys(obj) as unknown[] as T[];
    }

    type Color = keyof typeof kColors;
    const kAllColors = keysOf(kColors);

Above, Color is effectively an enum of only 'red', 'green', 'blue'. I can use it in any function and it will complain if I don't pass something provably 'red', 'green', or 'blue'. kAllColors is something I can iterate over all colors. And I can safely index `kColors` only by a Color

In most other languages I've used I'd have to first declare a separate enum for the type, then associate each of the "keys" with a value. Then separately make an array of enum values by hand for iteration, easy to get out of sync with the enum declaration.

Lots of languages can infer types. And your last example with the colors is just a dictionary.

Most languages have poor support for structural types though. If you try and join two records together (like a SQL join), what will your favourite language infer then?

C# has anonymous types which is pretty much the same thing. Though I prefer to declare actual types for most usecases, I'll only use anonymous types for intermediate results and such.

I certainly don't mean to knock nominal types. But I think structural types are more fundamental. A language would only need a single "newtype" or "nominal" keyword to create nominal types from structural types.

Why structural is more fundamental?

C#'s anonymous type shares some flexibility of structural type system even though it still a nominal type.

  > A language would only need a single "newtype" or "nominal" keyword to create nominal types from structural types.

I think you also can add `structural` keyword & apply structural type system in generally nominal type system as well if we're talking about adding feature.

Claude is "very good" in applying >var< continuously :-D

dictionaries generally aren't guaranteed to contain an entry for every possible value of the key type. while you could implement the colors example with a dictionary, ideally you'd want the type system to assure that given a Color, there will be a string associated with it

Sounds like enums with extra steps.

Enums aren't type safe in typescript

Sounds like a major flaw.

it’s Enuma associated with data without having to repeat yourself

If you have to define the Enums in one place and then repeat them all in another just to associate data with each one you’ve failed

Maybe you can elaborate but enums in Java or Kotlin easily have data associated with them.

    enum class Color(val rgb: Int) {
        RED(0xFF0000),
        GREEN(0x00FF00),
        BLUE(0x0000FF)
    }

It's not a dictionary (type-wise). "as const" is the magic ingredient.

What you are describing is structural types. It is indeed a mystery that these are so under used, especially as they are a cornerstone of type theory. Structural types are so useful that they creep into most languages in some way. Even in Java, the Kingdom of the Nouns, where the rulers refused to merge a pair class, functions essentially take tuple arguments and these tuples don't have to be named and defined. You can't return a tuple though, so there is an unfortunate asymmetry. In Haskell and OCaml, we like to describe functions in a structural way, so com.google.android.Predicate would be just "a -> Bool". You wouldn't have to convert your com.google.guava.Predicate. But even these languages lack structural records and variants and suffer for it.

By now I'm also convinced that structural typing is a better default. Nominal types are still useful to assign properties that are hard or impossible to encode with structure alone (e.g. string that is a valid email address) . But I haven't encountered any other examples yet, where I'm missing nominal types.

OCaml has structural variants in the form of polymorphic variants. On the product side, OCaml has objects, first-class modules, labelled tuples (since OCaml 5.4) which are all a form of structural records, with different trade-off in term of ergonomics.

Inferred types are really great, but I feel they do not scale. Inside a method/function? Generally fine, but the signature, including the return type, had better be explicit.

Also, I think there was some performance issue with too much inference? Could be wrong, could also be fixed.

This. As soon as you need to use the type in another function (e.g. function parameter), you'll discover that it's better to just write it out.

They do scale, but explicit types have two bonuses in my eyes:

1. can be read without a compiler, useful when reading PRs

2. They make the compiler work less, it's easier to check than infer

Even though that works reasonably well, you may still want to explicitly define your types/interfaces. In this example, if I do need to hardcode the data instead of fetching it somewhere, I would define the interface with "state" being a union of values, because there is nothing that stops you from using `state: 'ABC'` which would be hard to discover.

Not surprisingly, C# worlds the same way with the only exception that you have to declare the variables as “var” but they are still strongly typed

Technically you're also allowed to use anonymously typed objects as inferred generic typed parameters in method calls.

It's also not quite as easy to declare and build an array. You can't just write

  var arr = [ 1, 2, 3];

You have to write something like

  var arr = new int[] { 1, 2, 3 };

However if you have previously declared `arr` to be of type `int[]` (or another collection type such as `List<int>`), then you can write

  arr = [ 1, 2, 3 ];

I haven't used TypeScript so don't know if it distinguishes between arrays and lists, and if so how it determines one or the other in inferred types. Would be curious to know.

Type inference is part of every modern language. Structural typing not so much, though.

Java has it through a compiler extension (https://github.com/manifold-systems/manifold/tree/master/man...) but I don't know many other languages that support this feature.

As much as I dislike the entire Javascript runtime environment, I find TypeScript to be the best typing system out there for any imperative language.

> I don't know many other languages that support this feature

The other widely-used one is Go with its structurally-typed interfaces.

Right... But Go is exclusively structurally typed, whereas Java with the manifold compiler plugin complements the type system's nominal foundation -- a class can still implement a structural interface nominally. Doing so enforces intention and helps both people and tooling comprehend code faster and more efficiently. But the general idea is to use an interface structurally where it otherwise can't be used nominally or doing so is more complicated.

We need Anders to make one final language.

A MINIMAL memory safe language. The less it has the better.

Rust without the crazy town complexity.

The distilled wisdom from C# and Delphi and TypeScript.

A programming language that has less instead of more.

Sounds like golang to me

Without the features I identified,yes, you’re right!

Considering they used Go for the native compiler he might actually agree with you.

Oberon 07?

What would you take out of C# etc?

(not OP) I would take out mostly historic stuff, that is in there for backwards compat, that has been superseeded. But this could be achieved using linters.

All non-generic container classes and nullable reference types.

> nullable reference types.

What would you suggest instead? I quite like the nullable reference types, but I do know many get annoyed. My brain is often a scurry of squirrels, so I grew to become thankful for the nullable refs overtime.

I don't mind NRT but I hate dealing with C# projects that haven't set < Nullable>Enable</Nullable> in their csproj. It's not perfect because I know at runtime it can still be nullable but it's nice when the compiler does most of the checks for you.

The compiler now mostly solves this now but the abstraction is a little leaky.

I heavily use nullable types but I always want them to be declared nullable.

> Rust without the crazy town complexity.

To be clear, the language has a GC then?

I suppose it could have some kind of ARC. In theory some future languages could even have some hybrid approach? A high perf default but you can fallback to a GC allocation for hard things?

I'm pretty sure that there are multiple GC crates for Rust out there. But using them mixed in with non-GC variables presumably makes things more complex.

What about Lua? The language is very minimal, memory safe, and has Pascal-like syntax just like Delphi.

Lua's variables being global by default seems somewhat error-prone.

Agreed, but the recently-released v5.5 fixes that [0], and it's fairly easy to fix this in older versions with the following snippet

  setmetatable(_G, { __newindex = false, __index = false })

[0]: https://www.lua.org/manual/5.5/manual.html#2.2

verything is an off by one error in Lua.

Or conversely, everything is an off-by-one error in every other language :)

*everythin

I want something that will bring productivity of Delphi to Web. May be I am old now, but I could have built applications in a weekend in Access or Visual Basic that will take weeks now in latest web stack.

OutSystems, but it isn't cheap.

Right? I was hoping webassembly would bring back some proper gui tools like this to avoid the whole JS/DOM but no luck so far.

Blazor is pretty cool if you are into that kind of stuff. Mind you, you still might need the slightest tiny dash of JS, but depending on your needs, you might be able to get away from JS entirely.

Somewhere its in my list of things to try one day. Maybe an ai agent can help make this happen.

ASP.Net Web Forms still exists, though it is deprecated.

Eh. I admit I just use AI now when I want to quickly build a web app like that. I built a huge content management system in a couple of hours that way.

If you're talking Windows desktop apps like Delphi used to do, then Visual Studio WinForms is still just like that in 2026 and still getting updates.

C# is way to go then

>We need Anders to make one final language.

I do feel like there is a gap for a modern compiled, functional and garbage collected language.

Go isn't it because it lacks the functional constructs.

C# and Java aren't it because they depend on a VM.

Rust isn't it because of its difficult memory management.

Swift isn't it because it is so tied to Apple and their platforms.

C# doesn't depend on a VM these days when it is AOT compiled. Same for Java, though C# is rather more user friendly in how it goes about it.

> C# doesn't depend on a VM these days when it is AOT compiled

Maybe I’m being pedantic, but this is an oxymoron. Also the premise is incorrect. It’s not like the VM is gone. Merely baked into the code at compile time. It compiles IL to native code. Same for IL2CPP. The VM is still there.

The term “virtual machine” is confusing. I think you meant to say JIT compiler :-)

The trouble with that level of pedantry is that you then can point to LLVM as a VM and say that Clang and other C/C++/Rust tools that AOT through LLVM are "too tied to a virtual machine". Then you can go back through the history of cross-platform optimizing C/C++ compilers and find VMs in the design in almost all of those, too. LLVM is not hiding it in its very clear name, but low-level VMs were a thing for decades before someone named LLVM.

VMs have a long history in cross-compilation, even for "low-level" languages like C/C++. The AOT versus JIT distinction is blurry, and the "VM language" versus "non-VM language" boundary is blurrier still, especially when you take into account "standard runtimes" such as glibc and vcrt and whether or not those are statically linked.

Is a C program with a compiled with Clang through the LLVM dynamically linking a glibc and statically linking a Boehm GC library "running in a VM"? There's no wrong answer, it's a lot shades of gray. I believe almost every pedantic way to answer that has an equally pedantic counter-argument.

What you are looking for is called F#. You get native interop with C# and access to all .NET/C# libraries as a bonus. We use it as a daily driver for a complex B2B2C cloud platform.

Does it not run in a VM?

Yes you are right, it does not properly support NativeAOT yet.

But it isn't a need for most use cases, unless you want to do mobile development and meet app store policies. But even then, mature F# frameworks like Fable transpile your F# code to React & Cie.

It can be compiled, but that’s not the use case it was originally designed around, so it’s not quite as first class an experience as with Go or Rust.

You can embed the framework into the application so it is a single distributable.

Kotlin has a LLVM backend, among others.

There are plenty of languages in that niche you could be using. OCaml, Haskell, F#...

Roc might be that language one day. Not yet because it's pre-0.1.

C#, with default tooling, can compile without needing a VM, for windows, macOS, linux and some other platforms.

I wish that Nuget would show which packages are NativeAOT compatible.

It will probably get there one day since all BCL is annotated. Perhaps this is not done because you can have parts of the library be completely safe to use in AOT while another part not be.

That's the problem though. People want one language to be The One (tm) and that's just not possible. Your The One (tm) isn't mine.

I don't see why a VM is a problem, personally, and I like a lot of what C# has been exploring with `Span<T>` and `Memory<T>` for safe low-level memory management in a garbage-collected language. Some of it seems like a simpler Rust. Rust can still do plenty of memory lifetime things that C# can't, but the gap is smaller than ever and C# is still slowly growing its capabilities in that space. All that in a language where you don't have to start with the low level tools, you can prototype entirely in higher-level garbage collected space and use real world performance to guide optimizations towards the low-level memory management tools only when they become truly necessary.

The minimal memory-safe language is Go. Turns out it's too minimal for most.

It’s not memory safe.

Please elaborate. I've heard that you could break Go's memory safety through a race condition, but that's as far as my knowledge goes.

On the .Net VM you’re describing F#, mostly by virtue of being based on OCaml.

Contrasted with TypeScript and C#, F# is smaller, more expressive, stricter, with mature pattern matching and type resolution baked in from the ground up. F# was years ahead of the major languages on what are increasingly looking like ‘the basics’ around ADTs and immutability in modern distributed computing. OCaml and F# capture the linguistic high points of VB, Delphi, and C# with a broad spectrum of OOP(-lite) approaches, and have led those languages by decades on functional constructs that result in meaningfully tighter code. With the benefit of hindsight some approaches clearly map better to cloud computing and system verification.

F# also sits parallel to lots of living C#, objectively we see ‘less is more’. Less code per line, fewer lines per solution, terser and more LLM-efficient language. Error rates and refactoring costs are also meaningfully better IME, but harder to quantify in general terms.

It’s a great language. I just wish its compilation speed matched that of OCaml.

Yeah exactly.

Hardly, even Turbo Pascal 7 for MS-DOS is more advanced than Go's type system.

You don't have to use all the features of C#. I make my living at it and don't touch a lot of them. The issue with C# is culture. They went full in on blog driven development so there's way too many people who will yell this is the way to do things this week.

It's true. You will incur the wrath of C#'ers if your simple ToDo list app doesn't have a ToDoListItemRepositoryServiceFactory.cs and a minimum of 4 separate layers in which one must update 20 files because you added a property to one class.

Don't get me wrong, I still love C#/.NET. I use it everyday, but my god, has Swift been a breath of fresh air. The Swift community, when not whining about Swift UI, has been much less dogmatic in my experience.

I used to dream about a TypeScript that targeted dotnet. These days I'm not so sure I'd use it, only because I have a tendency to get caught in the weeds "big braining" the type system to make the perfect type for every situation. F# is my happy medium for the backend.

What's missing from C#?

Discriminated Unions is one thing I would like.

If we're talking about C# versus F#, then as the other person said, discriminated unions is the main reason I prefer F#. Pipes are excellent too, but I also just like the syntax more.

For C# versus TypeScript, it's primarily the type system. You've got DUs like F#, but you also have structural typing, dependent types, linear types, refinement types, string types, and so on. It's F#'s type system on steroids IMO.

That said, C# is a great language and I use it all the time. I have a modestly popular open-source package that I write primarily in C#; I do that to make sure it's ergonomic for a C# developer first and foremost (since it's the more popular dotnet language by far) before adding in considerations for VB or F# developers like myself.

Restraint.

The real history of C# is that it is a rip off of Java. Anders / Microsoft understandably doesn't want to acknowledge that, but the rest of us can. C# today has diverged from Java, but the original release was Java with a few features added, such as properties, delegates, structs and unchecked exceptions.

That last one was a mistake, see https://mckoder.medium.com/the-achilles-heel-of-c-why-its-ex...

Checked exceptions are bad because people just catch them and rethrow RuntimeException. Proper errors as data would be much preferable.

> people just catch them and rethrow

People don't have to. There is a lot of misinformation out there about checked exceptions, and people are responding to the misinformation.

Checked exceptions are proper errors as data. There is no difference between Result[T, E] and T throws E. The same people that just rethrow as RuntimeException would call unwrap() on Result and panic. The main problem with _Java_'s implementation of checked exceptions is that they're not fully in the type system because of Java's weak type system. That is solvable with a strong type system though, like in Scala or Swift.

You can misuse the errors as data paradigm just like you can misuse checked exceptions. That doesn't make either paradigm bad, it makes the programmers who misuse them bad.

MS poached him (and was even sued for it - that's how egregious it was) to create a Java killer because they had issues with Java.

> "Hejlsberg: First of all, C# is not a Java clone. ... we looked at lots of languages, we looked at Java"

- https://web.archive.org/web/20100109195800/http://windowsdev...

You can just state the author of the language is lying and you somehow know better. You don't even justify why "they don't want to acknoweldge it" - even with Hejlsberg there acknowledging taking ideas from Java - or explain why C# had those differences mentioned in the rest of that interview, or why Microsoft separately wrote their own Java implementation like Visual J++ if C# was just "their Java".

Completely agree, HN is mostly anti .NET/C#. It rarely gains attraction, and when it does, people bashes it with unfounded or very outdated info from another era.

Wrong! J# was Microsoft’s Java.

"Visual J++ is Microsoft's discontinued implementation of Java" - https://en.wikipedia.org/wiki/Visual_J%2B%2B

"J# does not compile Java-language source code to Java bytecode .. does not support Java applet development or the ability to host applets directly in a web browser" - https://en.wikipedia.org/wiki/Visual_J_Sharp

He literally says they're standing on the shoulders of Giants.

And, you would be stupid not to look at other languages.

How can you expect anything to be a clean slate to begin with? Is every oop language a rip off then?

Products don't get designed in a vacuum

> He literally says they're standing on the shoulders of Giants.

Yeah everyone says that. He should have called out one giant specifically: James Gosling.

> And, you would be stupid not to look at other languages.

Of course. Is that really what happened here? This was a literal clone. (And it is not like Microsoft never copies competitors' products.) Yes, they did add a few features.

I recently wrote a project in C# 2.0 and i actually had the opposite conclusion; the inspiration from Java is clearly there but even by 2.0 it had diverged pretty meaningfully

Yes the languages have diverged, especially the ecosystems. For big data projects Java/JVM languages are preferred. For many open source projects too, Java is preferred because C# was late to the OSS party. But for many enterprise web applications ASP.NET works well.

I was around in that era and yes when C# came out it was very obvious that Microsoft had been 'inspired' by the Java syntax ... Java had been the buzzword for the 5 years or so beforehand, like the only language that anyone talked about, so when Microsoft came up with C# it was glaringly obvious where they got the idea from.

On the other hand Java came with the VM ("write once run anywhere" as they used to say) but C# turned that inside out with the Common Langauge Runtime, so you had various languages like C# and VB.Net that compiled to the same bytecode.

The other innovation with Java back in the day was that it came with a huge library/framework of classes that did most of the stuff you would need to do. Similarly Microsoft's .NET library was a copy of that idea, although the frameworks themselves were pretty different.

They're also sweeping VB.NET under the rug.

If I had to bet, I would guess VB.NET was the more popular .NET language at first. Everyone I know was converting all their ASP pages and VB apps to VB.NET.

I didn't switch from VB.NET to C# as my main language until 2021. (the 90s was all C/C++/Java for me)

It is absolutely infuriating that Flash, ActionScript and ES4 draft were completely erased from history.

I was there since '00.

It all started with Macromedia and their animation tool. They had an idea to add simple scripting so you add commands like "stop" or "gotoAndPlay(n)" on your animation timeline. For whatever reason they chose to use EcmaScript (aka JS).

Soon after it turned out that people were doing actual programming and shortly after in 2003 they came up with updated version called ActionScript 2.0 that added all OOP features from Java. This became the EcmaScript 4 draft.

If you ever wondered why JS has reserved keywords like "abstract", "protected" or "interface" this is why.

What's funny is that by that time the underlying engine was still working on the old ES3 so when you compiled your app your code was transpiled in exact same way TS is transpiled into JS today.

We had MXML, which was XML for laying out your controllers and classes like we do today with React and web components.

We had Alchemy that allowed you to compile C directly into Flash bytecode - exactly what emscripten is doing. And there was even a way to write assembler directly if you were brave enough.

Around 2008 there was even a thing called RedTamarin which was... command line runtime for ActionScript, just like NodeJS.

And then Apple came, Flash was gone, and with it all these things.

All of these things were erased from memory, and for the next 10 years community was slowly reinventing the wheel.

Typescript is the best thing that happened to web development since web development.

I just hope they will not overengineer and ruin it moving forward

I think this ship has sailed.

which one?

It's interesting that some of the most successful programming languages (Turbo Pascal, C++, Delphi, Typescript) were designed by people born in Denmark.

Wasn’t he fired by MS?

No. He is a Microsoft Technical Fellow and still a core contributor to the TypeScript compiler.

If you feel that TypeScript, or hell even JavaScript, is becoming more alike C#, it's actually deliberately done by Microsoft in benefiting their ecosystem. In this interview they mentioned they had internal demands to convert/transpile C# into JavaScript or TypeScript. So by making these target languages more like C#, it directly benefits their need. But I don't think this should be the driving force in designing ECMAScript. When they are pushing a language feature, they have an unspoken internal goal, and every choice they make is to make JS/TS look more like C#, and they are more likely to dismiss proposals that preventing them from deliverying that goal. There's likely a bit of conflict of interest there.

It sounds like conspiracy theory that they design TS/JS to convert from C# easier, huh.

The truth is that C# is probably the best designed mainstream language out there.

C# was known as a language with lowest amount of WTF per LoC

that's the "evil MS" perspective

The sequence of turbo pascal / delphi / c# / typescript which brought us LSP as a sidekick (!) IMHO has benefitted the whole industry at least as much as "transpile c# to ecma script via typescript" . no. much much much more.

I do not see a problem with MS also having an internal use case .

you know I wouldn't stop using python "because" Guido now works at MS ...

Spot on.

Python has an elected steering council and core team. The governance process explicitly tries to avoid conflict of interest by disallowing more than two steering council members working for the same employer. See PEP 13 [1].

By contrast, .NET is controlled by Microsoft (with veto over board decisions [2] and code changes [3]), integrates Microsoft's telemetry to send your data to Microsoft by default [4] and deliberately hobbles features to benefit Microsoft [5].

[1] https://peps.python.org/pep-0013/

[2] https://dotnetfoundation.org/about/policies/.net-foundation-...

[3] https://github.com/dotnet/runtime/blob/main/CONTRIBUTING.md

[4] https://github.com/dotnet/sdk/issues/6145

[5] https://github.com/dotnet/sdk/issues/22247

According to the docs, .NET 10 has hot reload via the cli, unless I'm misunderstanding something: https://learn.microsoft.com/en-us/dotnet/core/tools/dotnet-w...

The complaint above was that JS was becoming too much like C#, so the steering committee of .NET isn't the one of the original concern. (Also, as pointed out, that "deliberate hobbling" case was litigated in the public square on HN at the time and then revised and "unhobbled" after the outcry.)

As far as the other direction, JS has a somewhat similar (but rather more complex) situation to Python with its steering committee being Ecma International's TC39 (Technical Committee 39).

Ecma International has similar By-Laws and Rules designed to manage conflict of interest and too much power consolidate in a single employer of committee members. Ecma is maybe even a little "stricter" than Python because its rules consider the companies themselves to be the members, and companies only get one vote no matter how many employees interact with the process.

https://ecma-international.org/policies/by-laws/

https://ecma-international.org/policies/rules/

Well, for one, benefiting Microsoft's ecosystem does not imply being detrimental to other ecosystems per se.

Furthermore, couldn't the convergence of TypeScript towards C# be simply a result of shared goals and values of the two languages, especially considering they have the same principal designer?

As a long term observer: definitely not a goal. But you have to be clear here: JavaScript and C# both are OO languages, both are having origins stories in Java/C++, both are facing the same niche (system development), same challenges (processor counts, ...) and so on. And then, you put teams on it which look left and right when they face a problem and then you wonder that they reuse what they like?

C# language team is also really good. They did not do a lot of mistakes in the 25+ years. They are a very valid source of OO and OO-hybrid concepts. It is not only TS/JS but also Java and C++ who often look to C#.

The story was not to transform C# code to JS but to use C# to write the code in the first place and transpile it. Not for the sake of having .NET usage but for the sake of having a good IDE.

> They did not do a lot of mistakes in the 25+ years

If my memory serves, .NET and WinFS were the two major forces that sunk Longhorn, and both have been given their walking papers after the reset [1].

.NET and C# have grown to be mature and well-engineered projects, but the road there was certainly not without bumps. It's just that a lot of the bad parts haven't spilled outside of Microsoft, thankfully.

[1] https://www.theregister.com/2005/05/26/dotnet_longhorn/

Are we mixing the language and the runtime here? C# the language seems weirdly free of weirdness and footguns.

Not only that, they went as deep as mixing in project issues with language design. A massive rewrite mixed with massive feature changes is always a tricky thing no matter the language.

.NET was already a going concern before Longhorn even started. What sank Longhorn was the fact that writing an OS from scratch is hard and maintaining compatibility with existing OSes in the process is even harder, especially when you're adopting a completely new architecture. Longhorn would have been a microkernel running 100% on the .NET runtime, mainline Windows is a monolithic kernel written in C++. I don't know how it would have ever worked, whether .NET was "perfect" or not.

See Android, or Meadows for alternative reality.

Android still runs on a monolithic kernel written in a memory-unsafe language. I'm finding it suprisingly difficult to find information on Meadow, other than it runs .NET DLLs as user-space applications, but nothing about the structure of the kernel.

Longhorn was going to be more than that. Microsoft did have Singularity/Midori projects, started around the middle of Longhorn/Vista, and continued much longer after Vista released to build out the managed microkernel concept. It's been about a decade since they've put any work into it, though.

Microsoft wasn't even able to deliver that, which was my whole point.

Joe Duffy mentions on a talk, that even with Midori running production workloads, Windows team could not be changed their mind.

Meadow uses a C++ based microkernel, the whole userspace is based on .NET, by the way.

No, Longhorn was neither a microkernel nor was the kernel rewritten in .NET.

Source: I was there.

I think he confuses longhorn with Singularity research project.

Nope, what sunk Longhorn was politics.

Windows team is a C++ kingdom, and those devs will not adopt .NET even at gun point.

They redid Longhorn with COM and called it WinRT, irony of ironies, WinRT applications run slower than .NET with COM reference counting all over the place.

Google has showed those folks what happens when everyone plays on the same team, and now it owns the mobile phone market, a managed userspace with 70% world market.

The article is presenting some stuff mixed up. Had nothing to do with the language or the framework. WinFS was a database product. Over engineered and abstract.

.NET and C# were researched a lot for operating system usage (Midori, Singularity) but that was after Longhorn.

The operating system group UI toolkits was a further problem and they pivoted there dozen of times in the years. Particular for a C++ based os group.

But the death of longhorn was ultimately about the security restart of Bill Gates

C# is inherently OOP oriented and it's type system works completely differently.

Not at all. Before the use of TypeScript exploded, they had two features brought into it from C# which were namespaces and enums (both of which are amazingly good features. For the first one, no one knew what was the right choice back then. We had almost a dozen different module systems and TypeScript had gone their way to support all of them and namespaces were their own solution to the mess (remember they were trying to solve their own problems at first, it wasn't to dominate anything). I personally used namespaces and I could have only the TypeScript compiler running and producing a single JS file for rapid development without the burden of --- then very slow --- webpack.

And for enums, using strings as enums was not a very efficient idea. I think JavaScript introduced Symbols for locked/hidden properties but also meant to use them as enums. It never worked either and then the sum type, union type feature of TypeScript made the whole community to keep using strings as enums. This is still a very bad idea, it is not ergonomic, it is prone to many problems, and very inefficient to compare strings instead of integers. But hey TypeScript tried to fix the problem and almost everyone rejected it. And so enum is now discontinued.

Rest of the changes to TypeScript came from almost any other language but C#, probably the biggest changes ever to happen to JavaScript came directly from CoffeeScript. And then I personally saw how each of these new changes --- one by one --- arrived at C#. For what I have seen firsthand by reading the TC39 proposals, each feature came from a different community and different programming languages, (think about null operators !/?, the nullish coalescing ??, the incoming pipes, fat arrows and lambdas, mixings) as JavaScript is the only language everyone has to use, and it has benefited everyone to have a language that has all the great things from all other languages.

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