Top
Best
New

Posted by ingve 12/21/2025

Rue: Higher level than Rust, lower level than Go(rue-lang.dev)
Related: https://steveklabnik.com/writing/thirteen-years-of-rust-and-...
257 points | 269 comments
xorvoid 12/22/2025|
"Memory Safe No garbage collector, no manual memory management. A work in progress, though."

I wish them the best, but until they have a better story here I'm not particularly interested.

Much of the complexity in Rust vs simplicity in Go really does come down to this part of the design space.

Rust has only succeeded in making a Memory Safe Language without garbage collection via significant complexity (that was a trade-off). No one really knows a sane way to do it otherwise, unless you also want to drop the general-purpose systems programming language requirement.

I'll be Very Interested if they find a new unexplored point in the design space, but at the moment I remain skeptical.

Folks like to mention Ada. In my understanding, Ada is not memory safe by contemporary definitions. So, this requires relaxing the definition. Zig goes in this direction: "let's make it as safe as possible without being an absolutist"

rayiner 12/22/2025||
If you look at the Github, there's a design proposal (under docs/design) for that.

It looks like the idea at the present time is to have four modes: value types, affine types, linear types, and rc types. Instead, of borrowing, you have an inout parameter passing convention, like Swift. Struct fields cannot be inout, so you can't store borrowed references on the heap.

I'm very interested in seeing how this works in practice--especially given who is developing Rue. It seems like Rust spends a lot of work enabling the borrow checker to be quite general for C/C++-like usage. E.g. you can store a borrowed reference to a struct on the stack into the heap if you use lifetime annotations to make clear the heap object does not outlive the stack frame. On the other hand it seems like a lot of the pain points with Rust in practice are not the lifetime annotations, but borrowing different parts of the same object, or multiple borrows in functions further down the call stack, etc.

delifue 12/23/2025|||
Not being able to store mutable ref in other type reduces expressiveness. The doc already mentions it cannot allow Iterator that doesn't consume container

https://github.com/rue-language/rue/blob/trunk/docs/designs/...

No silver bullet again

steveklabnik 12/23/2025|||
Just to be clear, these proposals are basically scratch notes I have barely even validated, I just wanted to be able to iterate on some text.

But yes, there is going to inherently be some expressiveness loss. There is no silver bullet, that's right. The idea is, for some users, they may be okay with that loss to gain other things.

steveklabnik 12/23/2025|||
For future readers, please use this link: https://github.com/rue-language/rue/blob/b0867ccff77ee9957d6...

I am going to be cleaning these up, as they don't necessarily represent things I actually want to do in this exact way. My idea was to dump some text and iterate on them, but I think that's actually not great given some other process changes I'm making, so I want to start fresh.

steveklabnik 12/22/2025|||
Yeah, that stuff is very much a sketch of the area I want to play in. It’s not final syntax nor semantics just yet. Gotta implement it and play around with it first (I have some naming tweaks I definitely want to implement separate from those ADRs.)

I don’t struggle with lifetimes either, but I do think there’s a lot of folks who just never want to think about it ever.

Someone 12/23/2025|||
> Rust has only succeeded in making a Memory Safe Language without garbage collection via significant complexity (that was a trade-off). No one really knows a sane way to do it otherwise, unless you also want to drop the general-purpose systems programming language requirement.

> I'll be Very Interested if they find a new unexplored point in the design space, but at the moment I remain skeptical.

They’re the somewhat sane “don’t allow dynamic allocations; just dimension all your arrays large enough” approach from the 1950s (Fortran, COBOL).

A variant could have “you can only allocate globals and must allocate each array exactly once before you ever access it”. That would allow dimensioning them from command line arguments or sizes of input files.

The type system then would have “pointer to an element of foo” types (could be implemented old-style as indices)

Yes, that would limit things, but with today’s 64-bit address spaces I think it could work reasonably well for many systems programming tasks.

It definitely would be significantly less complex than rust.

throwaway7356 12/23/2025||
> Yes, that would limit things, but with today’s 64-bit address spaces I think it could work reasonably well for many systems programming tasks.

As long as the systems programming tasks are strictly sequential, without threads, coroutines or signal handlers.

There is more to memory access than just out-of-bounds access which could be solved by just allocating every accessed memory page on demand as a slightly alteration of your variant.

Someone 12/24/2025||
Good points. As to signal handlers, I’m not aware of any language that fully supports them by making it impossible to call other than async-safe functions (https://man7.org/linux/man-pages/man7/signal-safety.7.html) from asynchrony signal handlers.
baranul 12/26/2025||
Wasn't Borgo[1] suppose to be the new child of Rust and Go too? Rue, is like the new replacement of Borgo, which hadn't been out for long.

On top of that, the original child of Rust and Go, was called Vlang[2].

[1]: https://borgo-lang.github.io/

[2]: https://www.youtube.com/watch?v=puy77WfM1Tg (Is V Lang Better Than Go And Rust? Let's Find Out)

steveklabnik 12/26/2025||
I don’t believe I’m familiar with Borgo. If I did see it before, I’d forgotten about it.

I am familiar with V.

killingtime74 12/21/2025||
I always thought of Go as low level and Rust as high level. Go has a lot of verbosity as a "better C" with GC. Rust has low level control but many functional inspired abstractions. Just try writing iteration or error handling in either one to see.
gpm 12/21/2025||
I wonder if it's useful to think of this as go is low type-system-complexity and rust is high type-system-complexity. Where type system complexity entails a tradeoff between the complexity of the language and how powerful the language is in allowing you to define abstractions.

As an independent axis from close to the underlying machine/far away from the underlying machine (whether virtual like wasm or real like a systemv x86_64 abi), which describes how closely the language lets you interact with the environment it runs in/how much it abstracts that environment away in order to provide abstractions.

Rust lives in high type system complexity and close to the underlying machine environment. Go is low type system complexity and (relative to rust) far from the underlying machine.

steveklabnik 12/22/2025|||
I think this is insightful! I'm going to ponder it, thank you. I think it may gesture towards what I'm trying to get at.
pron 12/22/2025|||
> Where type system complexity entails a tradeoff between the complexity of the language and how powerful the language is in allowing you to define abstractions.

I don't think that's right. The level of abstraction is the number of implementations that are accepted for a particular interface (which includes not only the contract of the interface expressed in the type system, but also informally in the documentation). E.g. "round" is a higher abstraction than "red and round" because the set of round things is larger than the set of red and round things. It is often untyped languages that offer the highest level of abstraction, while a sophisticated type system narrows abstraction (it reduces the number of accepted implementations of an interface). That's not to say that higher abstraction is always better - although it does have practical consequences, explained in the next paragraph - but the word "abstraction" does mean something specific, certainly more specific than "describing things".

How the level of abstraction is felt is by considering how many changes to client code (the user of an interface) is required when making a change to the implementation. Languages that are "closer to the underlying machine" - especially as far as memory management goes - generally have lower abstraction than languages that are less explicit about memory management. A local change to how a subroutine manages memory typically requires more changes to the client - i.e. the language offers a lower abstraction - in a language that's "closer to the metal", whether the language has a rich type system like Rust or a simpler type system like C, than a language that is farther away.

aw1621107 12/23/2025||
The way I understood the bit you quoted was not as a claim that more complex type system = higher abstraction level, but as a claim that a more complex type system = more options for defining/encoding interface contracts using that language. I took their comment as suggesting an alternative to the typical higher/lower-level comparison, not as an elaboration.

As a more concrete example, the way I interpreted GP's comment is that a language that is unable to natively express/encode a tagged union/sum type/etc. in its type system would fall on the "less complex/less power to define abstractions" side of the proposed spectrum, whereas a language that is capable of such a thing would fall on the other side.

> which includes not only the contract of the interface expressed in the type system, but also informally in the documentation

I also feel like including informal documentation here kind of defeats the purpose of the axis GP proposes? If the desire is to compare languages based on what they can express, then allowing informal documentation to be included in the comparison renders all languages equally expressive since anything that can't be expressed in the language proper can simply be outsourced to prose.

pron 12/23/2025||
But that's why the word "abstraction" is the wrong choice. The ability of a language to express detail and the ability of a language to have high abstractions are two different things, and when we talk about high and low level languages, I claim that what we intuitively mean is abstraction, not the expressivity of contracts. For example, ATS's contracts are virtually unlimited in their expressivity (it makes Rust indistinguishable from C by comparison), yet few would say it's particularly high-level. On the other hand, Scheme or even JavaScript can express few contracts, and yet are considered high level. I think that when we think of a high-level language, what we have in mind is a language where programs typically need to concern themselves with fewer details. This corresponds more with abstraction rather than "contract expressiveness".
aw1621107 12/23/2025||
> The ability of a language to express detail and the ability of a language to have high abstractions are two different things, and when we talk about high and low level languages, I claim that what we intuitively mean is abstraction, not the expressivity of contracts.

I think you're right with respect to discussion about abstractions in the context of high-/low-level languages, but again, I feel like what GP was trying to get away from the high-/low-level framing in the first place and might have meant something different when they used the word "abstraction".

Perhaps this is me misinterpreting things, but I took GP's use of "abstraction" as something more along the lines of what it might mean in "this library's abstractions are designed poorly/well because they are easy/hard to misuse and/or understand". In that context I think "abstraction" is more about the precise interface contract and its quality - e.g., a poorly-chosen abstraction might not reflect the domain it ostensibly represents well because it permits actions/behaviors that don't make sense for that domain, and that in part might be due to a language being unable to express a more appropriate contract. I feel that better matches GP's high-/low-type-system-complexity axis.

gpm 12/24/2025||
I agree with everything you're attributing to me for what it's worth :)
josephg 12/21/2025|||
Yep. This was the biggest thing that turned me off Go. I ported the same little program (some text based operational transform code) to a bunch of languages - JS (+ typescript), C, rust, Go, python, etc. Then compared the experience. How were they to use? How long did the programs end up being? How fast did they run?

I did C and typescript first. At the time, my C implementation ran about 20x faster than typescript. But the typescript code was only 2/3rds as many lines and much easier to code up. (JS & TS have gotten much faster since then thanks to improvements in V8).

Rust was the best of all worlds - the code was small, simple and easy to code up like typescript. And it ran just as fast as C. Go was the worst - it was annoying to program (due to a lack of enums). It was horribly verbose. And it still ran slower than rust and C at runtime.

I understand why Go exists. But I can't think of any reason I'd ever use it.

wswin 12/22/2025|||
Rust gets harder with codebase size, because of borrow checker. Not to mention most of the communication libraries decided to be async only, which adds another layer of complexity.
gpm 12/22/2025|||
I strongly disagree with this take. The borrow checker, and rust in general, keeps reasoning extremely local. It's one of the languages where I've found that difficulty grows the least with codebase size, not the most.

The borrow checker does make some tasks more complex, without a doubt, because it makes it difficult to express something that might be natural in other languages (things including self referential data structures, for instance). But the extra complexity is generally well scoped to one small component that runs into a constraint, not to the project at large. You work around the constraint locally, and you end up with a public (to the component) API which is as well defined and as clean (and often better defined and cleaner because rust forces you to do so).

orlp 12/22/2025||||
I work in a 400k+ LOC codebase in Rust for my day job. Besides compile times being suboptimal, Rust makes working in a large codebase a breeze with good tooling and strong typechecking.

I almost never even think about the borrow checker. If you have a long-lived shared reference you just Arc it. If it's a circular ownership structure like a graph you use a SlotMap. It by no means is any harder for this codebase than for small ones.

jrjrjfhgggg 12/22/2025||||
Disagree, having dealt with +40k LoC rust projects, bottow checker is not an issue.

Async is an irritation but not the end of the world ... You can write non asynchronous code I have done it ... Honestly I am coming around on async after years of not liking it... I wish we didn't have function colouring but yeah ... Here we are....

jesse__ 12/22/2025|||
We all know that lines of code is a poor measure of project size, but that said, 40k sloc is not a lot
tracker1 12/22/2025|||
Funny, I explicitly waited to see async baked in before I even started experimenting with Rust. It's kind of critical to most things I work on. Beyond that, I've found that the async models in rust (along with tokio/axum, etc) have been pretty nice and clean in practice. Though most of my experience is with C# and JS/TS environments, the latter of which had about a decade of growing pains.
josephg 12/22/2025||||
This hasn't been my experience at all.

I still regularly use typescript. One problem I run into from time to time is "spooky action at a distance". For example, its quite common to create some object and store references to it in multiple places. After all, the object won't be changed and its often more efficient this way. But later, a design change results in me casually mutating that object, forgetting that its being shared between multiple components. Oops! Now the other part of my code has become invalid in some way. Bugs like this are very annoying to track down.

Its more or less impossible to make this mistake in rust because of how mutability is enforced. The mutability rules are sometimes annoying in the small, but in the large they tend to make your code much easier to reason about.

C has multiple problems like this. I've worked in plenty of codebases which had obscure race conditions due to how we were using threading. Safe rust makes most of these bugs impossible to write in the first place. But the other thing I - and others - run into all the time in C is code that isn't clear about ownership and lifetimes. If your API gives me a reference to some object, how long is that pointer valid for? Even if I now own the object and I'm responsible for freeing it, its common in C for the object to contain pointers to some other data. So my pointer might be invalid if I hold onto it too long. How long is too long? Its almost never properly specified in the documentation. In C, hell is other people's code.

Rust usually avoids all of these problems. If I call a function which returns an object of type T, I can safely assume the object lasts forever. It cannot be mutated by any other code (since its mine). And I'm not going to break anything else if I mutate the object myself. These are really nice properties to have when programming at scale.

asa400 12/22/2025||
I wholeheartedly concur based on my experience with Rust (and other languages) over the last ~7 or so years.

> If I call a function which returns an object of type T, I can safely assume the object lasts forever. It cannot be mutated by any other code (since its mine). And I'm not going to break anything else if I mutate the object myself. These are really nice properties to have when programming at scale.

I rarely see this mentioned in the way that you did, and I'll try to paraphrase it in my own way: Rust restricts what you can do as a programmer. One can say it is "less powerful" than C. In exchange for giving up some power, it gives you more information: who owns an object, what other callers can do with that object, the lifetime of that object in relation to other objects. And critically, in safe Rust, these are _guarantees_, which is the essence of real abstraction.

In large and/or complicated codebases, this kind of information is critical in languages without garbage garbage collection, but even when I program in languages with garbage collection, I find myself wanting this information. Who is seeing this object? What do they know about this object, and when? What can they do with it? How is this ownership flowing through the system?

Most languages have little/no language-level notion of these concepts. Most languages only enforce that types line up nominally (or implement some name-identified interface), or the visibility of identifiers (public/private, i.e. "information hiding" in OO parlance). I feel like Rust is one of the first languages on this path of providing real program dataflow information. I'm confident there will be future languages that will further explore providing the programmer with this kind of information, or at least making it possible to answer these kinds of questions easier.

aw1621107 12/22/2025||
> I rarely see this mentioned in the way that you did, and I'll try to paraphrase it in my own way: Rust restricts what you can do as a programmer. One can say it is "less powerful" than C. In exchange for giving up some power, it gives you more information

Your paraphrasing reminds me a bit of structured vs. unstructured programming (i.e., unrestricted goto). Like to what you said, structured programming is "less powerful" than unrestricted goto, but in return, it's much easier to follow and reason about a program's control flow.

At the risk of simplifying things too much, I think some other things you said make for an interesting way to sum this up - Rust does for "ownership flow"/"dataflow" what structured programming did for control flow.

josephg 12/23/2025||
I really like this analogy. In a sense, C restricts what you can do compared to programming directly in assembly. Like, there's a lot of programs you can write in assembly that you can't write in the same way in C. But those restrictions also constrain all the other code in your program. And that's a wonderful thing, because it makes it much easier to make large, complex programs.

The restrictions seem a bit silly to list out because we take them for granted so much. But its things like:

- When a function is called, execution starts at the top of the function's body.

- Outside of unions, variables can't change their type halfway through a program.

- Whenever a function is called, the parameters are always passed using the system calling convention.

- Functions return to the line right after their call site.

Rust takes this a little bit further, adding more restrictions. Things like "if you have a mutable reference to to a variable, there are no immutable references to that variable."

tracker1 12/22/2025||||
I think it depends on the patterns in place and the actual complexity of the problems in practice. Most of my personal experience in Rust has been a few web services (really love Axum) and it hasn't been significantly worse than C# or JS/TS in my experience. That said, I'll often escape hatch with clone over dealing with (a)rc, just to keep my sanity. I can't say I'm the most eloquent with Rust as I don't have the 3 decades of experience I have with JS or nearly as much with C#.

I will say, that for most of the Rust code that I've read, the vast majority of it has been easy enough to read and understand... more than most other languages/platforms. I've seen some truly horrendous C# and Java projects that don't come close to the simplicity of similar tasks in Rust.

raincole 12/22/2025||||
Rust indeed gets harder with codebase size, just like other languages. But claiming it is because of borrow checker is laughable at best. Borrow checker is what keeps it reasonable because it limits the scope of how one memory allocation can affect the rest of your code.

If anything, borrow checker makes writing functions harder but combining them easier.

UltraSane 12/22/2025|||
async seems sensible for anything subject to internet latency.
yencabulator 12/25/2025||
Only in languages/runtimes without threads, like Javascript. In Rust, async vs threads is a performance tradeoffs (and it's definitely not always clear who the winner will be), and mostly relevant when you have tasks >> cores. Something like curl would have practically 0 reasons to be async, but of course is still subject to internet latency.
dent9 12/24/2025||||
> I understand why Go exists. But I can't think of any reason I'd ever use it.

When you want your project to be able to cross-compile down to a static binary that the end user can simply download and run without any "installation" on any mainstream OS + CPU arch combination

From my M1 Mac I can compile my project for Linux, MacOS, and Windows, for x86 and ARM for each. Then I can make a new Release on GitHub and attach the compiled binaries. Then I can curl the binaries down to my bare Linux x86 server and run them. And I can do all of this natively from the default Go SDK without installing any extra components or system configurations. You don't even need to have Go installed on the recipient server or client system. Don't even need a container system either to run your program anywhere.

You cannot do this with any other language that you listed. Interpreted languages all require a runtime on the recipient system + library installation and management, and C and Rust lack the ability to do native out-of-the-box cross compilation for other OS + CPU arch combinations.

Go has some method to implement enums. I never use enums in my projects so idk how the experience compares to other systems. But I'm not sure I would use that as the sole criteria to judge the language. And you can usually get performance on par with any other garage collected language out of it.

When you actually care about the end user experience of running the program you wrote, you choose Go.

9rx 12/22/2025||||
> it was annoying to program (due to a lack of enums)

Typescript also lacks enums. Why wasn't it considered annoying?

I mean, technically it does have an enum keyword that offers what most would consider to be enums, but that keyword behaves exactly the same as what Go offers, which you don't consider to be enums.

josephg 12/22/2025|||
In typescript I typed my text editing operations like this:

    type Operation = {type: “insert”, …} | {type: “delete”, …} | …;
It’s trivial to switch based on the type field. And when you do, typescript gives you full type checking for that specific variant. It’s not as efficient at runtime as C, but it’s very clean code.

Go doesn’t have any equivalent to this. Nor does go support tagged unions - which is what I used in C. The most idiomatic approach I could think of in Go was to use interface {} and polymorphism. But that was more verbose (~50% more lines of code) and more error prone. And it’s much harder to read - instead of simply branching based on the operation type, I implemented a virtual method for all my different variants and called it. But that spread my logic all over the place.

If I did it again I’d consider just making a struct in go with the superset of all the fields across all my variants. Still ugly, but maybe it would be better than dynamic dispatch? I dunno.

I wish I still had the go code I wrote. The C, rust, swift and typescript variants are kicking around on my github somewhere. If you want a poke at the code, I can find them when I’m at my desk.

hombre_fatal 12/22/2025|||
They presumably mean tagged unions like `User = Guest | LoggedIn(id, username)`.
9rx 12/22/2025||
That wouldn't explain C, then, which does not have sum types either.

All three languages do have enums (as it is normally defined), though. Go is only the odd one out by using a different keyword. As these programs were told to be written as carbon copies of each other, not to the idioms of each language, it is likely the author didn't take time to understand what features are available. No enum keyword was assumed to mean it doesn't exist at all, I guess.

josephg 12/22/2025||
C has numeric enums and tagged unions, which are sum types without any compile time safety. That’s idiomatic C.

Go doesn’t have any equivalent. How do you do stuff like this in Go, at all?

I’ve been programming for 30+ years. Long enough to know direct translations between languages are rarely beautiful. But I’m not an expert in Go. Maybe there’s some tricks I’m missing?

Here’s the problem, if you want to have a stab at it. The code in question defines a text editing operation as a list of editing components: Insert, Delete and Skip. When applying an editing operation, we start at the start of the document. Skip moves the cursor forward by some specified length. Insert inserts at the current position and delete deletes some number of characters at the position.

Eg:

    enum OpComponent {
        Skip(int),
        Insert(String),
        Delete(int),
    }

    type Op = List<OpComponent>
Then there’s a whole bunch of functions with use operations - eg to apply them to a document, to compose them together and to do operational transform.

How would you model this in Go?

9rx 12/22/2025||
> C has numeric enums and tagged unions

C has unions, but they're not tagged. You can roll your own tagged unions, of course, but that's moving beyond it being a feature of the language.

> How would you model this in Go?

I'm committing the same earlier sin by trying to model it from the solution instead of the problem, so the actual best approach might be totally different, but at least in staying somewhat true to your code:

    type OpComponent interface { op() }
    type Op = []OpComponent

    type Skip struct { Value int }
    func (s Skip) op() {}
    type Insert struct { Value string }
    func (i Insert) op() {}
    type Delete struct { Value int }
    func (d Delete) op() {}

    op := Op{
        Skip{Value: 5},
        Insert{Value: "hello"},
        Delete{Value: 3},
    }
josephg 12/22/2025||
> C has unions, but they're not tagged. You can roll your own tagged unions, of course, but that's moving beyond it being a feature of the language.

This feels like a distinction without a real difference. Hand-rolled tagged unions are how lots of problems are approached in real, professional C. And I think they're the right tool here.

> the actual best approach might be totally different, but at least in staying somewhat true to your code: (...)

Thanks for having a stab at it. This is more or less what I ended up with in Go. As I said, I ended up needing about 50% more lines to accomplish the same thing in Go using this approach compared to the equivalent Typescript, rust and swift.

If anyone is curious, here's my C implementation: https://github.com/ottypes/libot

Swift: https://github.com/josephg/libot-swift

Rust: https://github.com/josephg/textot.rs

Typescript: https://github.com/ottypes/text-unicode

I wish I'd kept my Go implementation. I never uploaded it to github because I was unhappy with it, and I accidentally lost it somewhere along the way.

> the actual best approach might be totally different

Maybe. But honestly I doubt it. I think I accidentally chose a problem which happens to be an ideal use case for sum types. You'd probably need a different problem to show Go or C# in their best light.

But ... sum types are really amazing. Once you start using them, everything feels like a sum type. Programming without them feels like programming with one of your hands tied behind your back.

9rx 12/23/2025||
> As I said, I ended up needing about 50% more lines to accomplish the same thing in Go

I'd be using Perl if that bothered me. But there is folly in trying to model from a solution instead of the problem. For example, maybe all you needed was:

    type OpType int
    const (
        OpTypeSkip OpType = iota
        OpTypeInsert
        OpTypeDelete
    )

    type OpComponent struct {
        Type OpType
        Int int
        Str string
    }
Or something else entirely. Without fully understanding the exact problem, it is hard to say what the right direction is, even where the direction you chose in other language is the right one for that language. What is certain is that you don't want to write code in language X as if it were language Y. That doesn't work in programming languages, just as it does not work in natural languages. Every language has their own rules and idioms that don't transfer to another. A new language means you realistically have to restart finding the solution from scratch.

> You'd probably need a different problem to show Go or C# in their best light.

That said, my profession sees me involved in working on a set of libraries in various languages, including Go and Typescript, that appear to be an awful lot like your example. And I can say from that experience that the Go version is much more pleasant to work on. It just works.

I'll agree with you all day every day that the Typescript version's types are much more desirable to read. It absolutely does a better job at modelling the domain. No question about it. But you only need to read it once to understand the model. When you have to fight everything else beyond that continually it is of little consolation how beautiful the type definitions are.

You're right, though, it all depends on what you find most important. No two programmers are ever going to ever agree on what to prioritize. You want short code, whereas I don't care. Likewise, you probably don't care about the things I care about. Different opinions is the spice of life, I suppose!

josephg 12/23/2025||
Yes I think I mentioned in another comment that that would be another way to code it up. It’s ugly in a different way to the interface approach. I haven’t written enough go to know which is the least bad.

What are you “fighting all day” in typescript? That’s not my experience with TS at all.

What are the virtues of go, that you’re so enamoured by? If we give up beauty and type safety, what do you get in trade?

9rx 12/23/2025||
I don't become enamoured by language. I really don't care if I have to zig or zag. I'll happily work in every language under the sun. It is no more interesting than trying to determine if Milwaukee or Mikita make a better drill. Who cares? Maybe you have to press a different button, but they both do the same thing in the end. As far as I'm concerned, It's all just 1s and 0s at the end of the day.

However, I have found the Go variant of said project to be more pleasant because, as before, it just works. The full functionality of those libraries is fairly complex and it has had effectively no bugs. The Typescript version on the other hand... I am disenchanted by software that fails.

Yeah, you can blame the people who have worked on it. Absolutely. A perfect programmer can program bug-free code in every language. But for all the hand-wringing about how complex types are supposed to magically save you from making mistakes that keeps getting trumped around here, I shared it as a fun anecdote to the opposite — that, under real-world conditions where you are likely to encounter programers that aren't perfect, Go actually excelled in a space that seems to reflect your example.

But maybe it's not the greatest example to extol the virtues of a language. I don't know, but I am not going to start caring about one language over another anyway. I'm far more interested in producing great software. Which brand of drill was used to build that software matters not one bit to me. But to each their own. Different opinions is the spice of life, I suppose!

andrewmcwatters 12/22/2025|||
There's a lot of ecosystem behind it that makes sense for moving off of Node.js for specific workloads, but isn't as easily done in Rust.

So it works for those types of employers and employees who need more performance than Node.js, but can't use C for practical reasons, or can't use Rust because specific libraries don't exist as readily supported by comparison.

steveklabnik 12/21/2025|||
Rue author here, yeah I'm not the hugest fan of "low level vs high level" framing myself, because there are multiple valid ways of interpreting it. As you yourself demonstrate!

As some of the larger design decisions come into place, I'll find a better way of describing it. Mostly, I am not really trying to compete with C/C++/Rust on speed, but I'm not going to add a GC either. So I'm somewhere in there.

written-beyond 12/21/2025|||
How very so humble of you to not mention being one of the primary authors behind TRPL book. Steve you're a gem to the world of computing. Always considered you the J. Kenji of the Rust world. Seems like a great project let's see where it goes!
steveklabnik 12/21/2025||
That is a very kind thing to say, I admire him quite a bit. Thank you!
killingtime74 12/21/2025||||
Wow didn't realise it was you who was the author. I learnt a lot about Rust from your writings.
steveklabnik 12/22/2025||
I'm glad to have helped you :)
AdieuToLogic 12/22/2025||||
> Mostly, I am not really trying to compete with C/C++/Rust on speed, but I'm not going to add a GC either. So I'm somewhere in there.

Out of curiosity, how would you compare the goals of Rue with something like D[0] or one of the ML-based languages such as OCaml[1]?

EDIT:

This is a genuine language design question regarding an imperative/OOP or declarative/FP focus and is relevant to understanding the memory management philosophy expressed[2]:

  No garbage collector, no manual memory management. A work 
  in progress, though.

0 - https://dlang.org/

1 - https://ocaml.org/

2 - https://rue-lang.dev/

steveklabnik 12/22/2025||
Closer to an OCaml than a D, in terms of what I see as an influence. But it's likely to be more imperative/FP than OOP/declarative, even though I know those axes are usually considered to be the way you put them than the way I put them.
AdieuToLogic 12/23/2025||
> But it's likely to be more imperative/FP than OOP/declarative, even though I know those axes are usually considered to be the way you put them than the way I put them.

Fascinating.

I look forward to seeing where you go with Rue over time.

manaskarekar 12/21/2025||||
Since it's framed as 'in between' Rust and Go, is it trying to target an intersection of both languages' use-cases?
steveklabnik 12/21/2025||
I don't think you'd want to write an operating system in Rue. I may not include an "unsafe" concept, and will probably require a runtime. So that's some areas where Rust will make more sense.

As for Go... I dunno. Go has a strong vision around concurrency, and I just don't have one yet. We'll see.

ChrisSD 12/22/2025||
Do you have plans for handling C FFI without "unsafe"? Will it require some sort of extension module written in C/C++/Rust?
steveklabnik 12/22/2025||
No direct plans. For the immediate future, only the runtime is allowed to call into C.

If this ever becomes a production thing, then I can worry about FFI, and I'll probably just follow what managed languages do here.

tracker1 12/22/2025||
FWIW, I really like the way C# has approached this need... most usage is exposed via attribute declaration/declaration DllImport for P/Invoke. Contrasted with say JNI in Java or even the Go syntax. The only thing that might be a significant improvement would be an array/vector of lookup names for the library on the system given how specific versions are often tagged in Linux vs Windows.
pron 12/22/2025||||
> because there are multiple valid ways of interpreting i

There are quantitative ways of describing it, at least on a relative level. "High abstraction" means that interfaces have more possible valid implementations (whether or not the constraints are formally described in the language, or informally in the documentation) than "low abstraction": https://news.ycombinator.com/item?id=46354267

dxxvi 12/23/2025||||
You couldn't get the rue-lang.org domain? There are rust-lang.org, scala-lang.org, so rue-lang.org sounds better than .dev.

I'd love to see how Rue solves/avoids the problems that Rust's borrow checker tries to solves. You should put it on the 1st page, I think.

steveklabnik 12/23/2025||
Already taken.

I'll put more about that there once it's implemented :)

chrysoprace 12/22/2025||||
Do you think you'll explore some of the same problem spaces as Rust? Lifetimes and async are both big pain points of Rust for me, so it'd be interesting to see a fresh approach to these problems.

I couldn't see how long-running memory is handled, is it handled similar to Rust?

steveklabnik 12/22/2025||
I'm going to try and avoid lifetimes entirely. They're great in Rust! But I'm going to a higher level spot.

I'm totally unsure about async.

Right now there's no heap memory at all. I'll get there :) Sorta similar to Rust/Swift/Hylo... we'll see!

lamontcg 12/22/2025||
So if you don't have a garbage collector, and you don't have manual memory management, and you don't have lifetimes... What do you have?
steveklabnik 12/22/2025||
The plan is something like mutable value semantics and linear types. I'm figuring it out :)
ksec 12/22/2025||||
Is this a simplified / distilled version of Rust ? Or Subset of Rust with some changes ?
steveklabnik 12/22/2025|||
Some of it is like that, but some of it is going to be from other stuff too. I'm figuring it out :)
rob74 12/22/2025|||
Simplified as in easier to use, or simplified as in less language features? I'm all for the former, while the latter is also worth considering (but hard to get right, as all the people who consider Go a "primitive" language show)...
a96 12/22/2025|||
Since that seems to be the (frankly bs) slogan that almost entirely makes up the languages lading page, I expect it's really going to hurt the language and/or make it all about useless posturing.

That said, I'm an embedded dev, so the "level" idea is very tangible. And Rust is also very exciting for that reason and Rue might be as well. I should have a look, though it might not be on the way to be targeting bare metal soon. :)

steveklabnik 12/22/2025||
I don't mind if a sentence I threw up for a side project "hurts the language" at this stage, this is a project primarily for me.

You should use Rust for embedded, I doubt Rue will ever be good for it.

gf000 12/23/2025|||
Low and high level are not well-defined concepts.

One, objective definition is simply that everything that is not an assembly is a high-level language - but that is quite a useless def. The other is about how "deeply" you can control the execution, e.g. you have direct control of when and what gets allocated, or some control over vectorization, etc.

Here Rust is obviously as low-level as C, if not more so (both have total control over allocations, but still leaves calling conventions and such up to the compiler), while go is significantly higher (the same level as C#, slightly lower than Java - managed language with a GC and value types).

The other often mistaken spectrum is expressivity, which is not directly related to low/high levelness. E.g. both Rust and Scala are very expressive languages, but one is low, the other is high level. C and Go both have low expressivity, and one is low the other is high level.

This answer is imo a very must have read about the topic of expressivity: https://langdev.stackexchange.com/a/2016

asim 12/22/2025|||
Agree with Go being basically C with string support and garbage collection. Which makes it a good language. I think rust feels more like a c++ replacement. Especially syntactically. But each person will say something different. If people can create new languages and there's a need then they will. Not to say it's a good or bad thing but eventually it would be good to level up properly. Maybe AI does that.
pjmlp 12/22/2025|||
All are high level as long as they don't expose CPU capabilities, even ISO C is high level, unless we count in language extensions that are compiler specific, and any language can have compiler extensions.
9rx 12/22/2025||
C pointers expose CPU capabilities.

You can always emulate functionality on different architectures, though, so where is the practical line even drawn?

pjmlp 12/22/2025||
C pointers are nothing special, plenty of languages expose pointers, even classical BASIC with PEEK and POKE.

The line is blurred, and doesn't help that some folks help spread the urban myth C is special somehow, only because they never bother with either the history of programming language, and specially the history of systems programming outside Bell Labs.

9rx 12/22/2025||
They're nothing special, but were designed for a particular CPU and expose the details of that CPU. And since we were talking about C specifically, not a bunch of other random languages that may have did similar things...

While most modern CPUs are designed for C and thus share in the same details, if your CPU is of a different design, you have to emulate the behaviour. Which works perfectly fine — but the question remains outstanding: Where does the practical line get drawn? Is 6502 assembler actually a high-level language too? After all, you too can treat it as an abstract machine and emulate its function on any other CPU just the same as you do with C pointers.

stared 12/22/2025|||
I think it is precisely why Rust is gold - you can pick the abstraction level you work at. I used it a lot when simulating quantum physics - on one hand, needed to implement low-level numerical operations with custom data structures (to squeeze as much performance as possible), on the other - be able to write and debug it easily.

It is similar to PyTorch (which I also like), where you can add two tensors by hand, or have your whole network as a single nn.Module.

batisteo 12/21/2025|||
C was designed as a high level language and stayed so for decades
AdieuToLogic 12/22/2025||
> C was designed as a high level language and stayed so for decades

C was designed as a "high level language" relative to the assembly languages available at the time and effectively became a portable version of same in short order. This is quite different to other "high level languages" at the time, such as FORTRAN, COBOL, LISP, etc.

pjmlp 12/22/2025||
When C was invented, K&R C, it was hardly lower level than other systems programming languages that predated it, since JOVIAL in 1958.

It didn't not even had compiler intrisics, a concept introduced by ESPOL in 1961, allowing to program Burroughs systems without using an external Assembler.

K&R C was high level enough that many of the CPU features people think about nowadays when using compiler extensions, as they are not present in the ISO C standard, had to be written as external Assembly code, the support for inline Assembly came later.

AdieuToLogic 12/23/2025||
I think we are largely saying the same thing, as described in the introduction of the K&R C book:

  C is a relatively "low level" language. This
  characterization is not pejorative; it simply means that C
  deals with the same sort of objects that most computers do,
  namely characters, numbers, and addresses.[0]
0 - https://dn710204.ca.archive.org/0/items/the-c-programming-la...
dismalaf 12/23/2025||
Go has a GC and Rust doesn't. That alone makes Go higher level.
andsoitis 12/21/2025||
> Memory Safe

> No garbage collector, no manual memory management. A work in progress, though.

I couldn't find an explanation in the docs or elsewhere how Rue approaches this.

If not GC, is it via:

a) ARC

b) Ownership (ala Rust)

c) some other way?

steveklabnik 12/21/2025||
I am playing around with this! I'm mostly interested in something in the space of linear types + mutable value semantics.
onlyrealcuzzo 12/22/2025|||
Also working on a language / runtime in this space.

It transpiles to Zig, so you have native access to the entire C library.

It uses affine types (simple ownership -> transfers via GIVE/TAKES), MVCC & transactions to safely and scalably handle mutations (like databases, but it scales linearly after 32 cores, Arc and RwLock fall apart due to Cache Line Bouncing).

It limits concurrent complexity only to the spot in your code WHERE you want to mutate shared memory concurrently, not your entire codebase.

It's memory and liveness safe (Rust is only memory safe) without a garbage collector.

It's simpler than Go, too, IMO - and more predictable, no GC.

But it's nearly impossible to beat Go at its own game, and it's not zero overhead like Rust - so I'm pessimistic it's in a "sweet spot" that no one will be interested in.

Time will tell.

Imustaskforhelp 12/22/2025|||
can you share the link, sounds fascinating language to follow its development as well and good luck on this project!
steveklabnik 12/22/2025|||
Neat! Good luck, that sounds very cool. I have no idea what if anything I'm going to do about liveliness.
jasonwatkinspdx 12/22/2025||||
You might find one of my late brother's research interests relevant: https://www.cs.princeton.edu/~dpw/papers/space.pdf
steveklabnik 12/22/2025||
Thank you for the link! I'll check it out for sure.

(And sorry to hear about your brother's passing.)

jasonwatkinspdx 12/22/2025||
Yeah, that's just one of the essays he was on as a phd student, but he was really interested in the interaction of linear types and region inferencing as a general resource management framework. That grew into an interest in linear types as part of logical frameworks for modeling concurrency. But then like a lot of people he became disillusioned with academia, went to make some money on wall street, then focused on his family after that.

Anyhow, I just thought it might be a good jumping off point for what you're exploring.

echelon 12/21/2025||||
Nice! I see you're one of (if not the primary) contributor!

Do you see this as a prototype language, or as something that might evolve into something production grade? What space do you see it fitting into, if so?

You've been such a huge presence in the Rust space. What lessons do you think Rue will take, and where will it depart?

I see compile times as a feature - that's certainly nice to see.

steveklabnik 12/21/2025||
This is a project between me and Claude, so yeah :)

It's a fun project for me right now. I want to just explore compiler writing. I'm not 100% sure where it will lead, and if anyone will care or not where it ends up. But it's primarily for me.

I've described it as "higher than Rust, lower than Go" because I don't want this to be a GC'd language, but I want to focus on ergonomics and compile times. A lot of Rust's design is about being competitive with C and C++, I think by giving up that ultra-performance oriented space, I can make a language that's significantly simpler, but still plenty fast and nice to use.

We'll see.

echelon 12/22/2025||
Love it! I think that's a nice target.

Have fun! :)

torginus 12/22/2025||||
Could you please explain what this implies in layman's terms? I've read the definition of 'linear type' as a type that must be used exactly once, and by 'mutable value semantics', I assume, that unlike Rust, multiple mutable borrows are allowed?

What's the practical implication of this - how does a Rue program differ from a Rust program? Does your method accept more valid programs than the borrow checker does?

steveklabnik 12/22/2025||
I’m on my phone on a long road trip, so I can’t really give you a good lengthy explanation right now, to be honest.

Mutable value semantics means no references at all, from a certain perspective.

You can sort of think of linear types as RAII where you must explicitly drop. Sorta.

“More programs” isn’t really the right way to think about it. Different semantics, so different programs :)

sureglymop 12/22/2025||||
Have you explored the ideas explored for the Vale language: https://vale.dev/

May be an interesting approach. That language seems very academic and slow moving at the moment though.

steveklabnik 12/22/2025||
I think Vale is interesting, but yeah, they have had some setbacks, in my understanding more to do with the personal lives of the author rather than the ideas. I need to spend more time with it.
oulipo2 12/21/2025|||
So linear type + mutable value would be quite close to Rust, right?
steveklabnik 12/21/2025||
Rust has affine types, not linear. It also doesn't have mutable value semantics, it uses references, lifetimes, and borrowing.
EnPissant 12/21/2025||
I've never seen any significant difference in linear vs affine types.

To me it just seems like Rust has Linear types, and the compiler just inserts some code to destroy your values for you if you don't do it yourself.

I guess the only difference is that linear types can _force_ you to manually consume a value (not necessarily via drop)? Is that what you are going for?

steveklabnik 12/21/2025||
Affine types are "may use" and linear types are "must use," yeah. That is, linear types are stronger.

See https://faultlore.com/blah/linear-rust/ for a (now pretty old but still pretty relevant, I think) exploration into what linear types would mean for Rust.

pjmlp 12/22/2025|||
ARC is GC, chapter 5.

https://gchandbook.org/

andsoitis 12/22/2025||
Sure, ARC is a form of very specific, constrained garbage collection.

Compile-time, reference-counting GC, not runtime tracing GC. So no background collector, no heap tracing, and no stop-the-world pauses. Very different from the JVM, .Net, or Go.

pjmlp 12/22/2025||
Reference counting is a GC algorithm from CS point of view, it doesn't matter if it is compile time or runtime.

Additionally there isn't a single ARC implementation that is 100% compile time, that when looking at the generated machine code has removed all occurrences from RC machinery.

gf000 12/23/2025|||
While I am usually the one that also goes in and correct people incorrectly calling RC not a GC, the important distinction here is that Rust (and C++) has the necessary language constructs to be able to implement ref counting entirely as a library.
pjmlp 12/23/2025||
Which is a performance bottleneck, as the compiler is blind to library implementations and cannot optimise accordingly.

Also implementation has nothing to do with CS definition, there are tracing GC libraries for C as well.

gf000 12/23/2025||
I agree with your first point, and I didn't say anything contrary to your second.

My point is about crossing the misunderstanding between the "two camps".

pjmlp 12/24/2025||
Fair enough.
Warwolt 12/23/2025|||
But common, collouqialy "Garbage Collection" as a language feature refers to a run time garbage collector.

Saying that the language has GC just because it has opt-in reference counting is needlessly pedantic

pjmlp 12/23/2025||
Knowlege gets taught in specific institutions exactly because street knowledge is quite often incorrect, like in this case, spreading urban myths based in shaky foundations.
freakynit 12/22/2025||
Check out V-lang ... it has the details. It's a beautiful language... but, mostly unknown.
aw1621107 12/22/2025|||
> Check out V-lang ... it has the details.

Does it? From its docs [0]:

> There are 4 ways to manage memory in V.

> The default is a minimal and a well performing tracing GC.

> The second way is autofree, it can be enabled with -autofree. It takes care of most objects (~90-100%): the compiler inserts necessary free calls automatically during compilation. Remaining small percentage of objects is freed via GC. The developer doesn't need to change anything in their code. "It just works", like in Python, Go, or Java, except there's no heavy GC tracing everything or expensive RC for each object.

> For developers willing to have more low-level control, memory can be managed manually with -gc none.

> Arena allocation is available via a -prealloc flag. Note: currently this mode is only suitable to speed up short lived, single-threaded, batch-like programs (like compilers).

So you have 1) a GC, 2) a GC with escape analysis (WIP), 3) manual memory management, or 4) ...Not sure? Wasn't able to easily find examples of how to use it. There's what appears to be its implementation [1], but since I'm not particularly familiar with V I don't feel particularly comfortable drawing conclusions from a brief glance through it.

In any case, none of those stand out as "memory safety without GC" to me.

[0]: https://docs.vlang.io/memory-management.html

[1]: https://github.com/vlang/v/blob/master/vlib/builtin/prealloc...

freakynit 12/22/2025||
"none of those stand out as "memory safety without GC" to me" ... can you explain why you believe they are not memory safe without GC? Im more interested to know the points in relation to autofree.

Regarding the details, here is a pretty informative github discussion thread on same topic: https://github.com/vlang/v/discussions/17419

It is also accompanied with a demo video (pretty convincing in case you would like to watch).

V-lang is not shiny as other languages are, but, it does have a lot to learn from.

aw1621107 12/22/2025|||
> Im more interested to know the points in relation to autofree.

As sibling said, autofree is still stated to use a GC, which obviously disqualifies it from "memory safety without GC".

> Regarding the details, here is a pretty informative github discussion thread on same topic: https://github.com/vlang/v/discussions/17419

I did see that! Unfortunately it doesn't really move the needle on anything I said earlier. It describes manual memory management as an alternative to the GC when using autofree (which obviously isn't conducive to reliable memory safety barring additional guardrails not described in the post) and arenas are only mentioned, not discussed in any real detail.

> It is also accompanied with a demo video (pretty convincing in case you would like to watch).

Keep in mind the context of this conversation: whether V offers memory safety without GC or manual memory management. Strictly speaking, a demonstration that autofree works in one case is not sufficient to show V is memory safe without GC/manual memory management, as said capability is a property over all programs that can be written in a language. As a result, thoroughly describing how V supposedly achieves memory safety without a GC/manual memory management would be far more convincing than showing/claiming it works in specific cases.

As an example of what I'm trying to say, consider a similar video but with a leak/crash-free editor written in C. I doubt anyone would consider that video convincing proof that C is a memory-safe language; at most, it shows that memory-safe programs can be written in C, which is a very different claim.

baranul 12/26/2025||
Autofree can be combined with other memory management methods, besides GC, and is something V developers have hinted at multiple times. Until autofree becomes the focus of the project, combining it with the already existing GC, looks to have been and is more convenient.
aw1621107 12/27/2025||
> Autofree can be combined with other memory management methods, besides GC, and is something V developers have hinted at multiple times.

I'm just working off of what I could easily find, particularly in public docs. If the V devs have hinted at possibilities other than manual memory management and GC, then you are certainly better positioned than me to know about them.

Are the hints you mention publicly visible somewhere? Would be interesting to see more details if they're available.

forgotpwd16 12/22/2025||||
As read in quote given by GP, `autofree` partially uses a GC. And is WIP. (Although was supposedly production-ready 5+ years ago.)

Reading "Memory safe; No garbage collector, no manual memory management" on Rue homepage made me think of V for this very reason. Many think is trivial to do it and Rust has been in wrong for 15 years with its "overcomplicated" borrow checking. It isn't.

baranul 12/26/2025|||
The issue is that autofree is not a 100% solution by itself, in all circumstances. Thus it relies on the existing GC, in situations that it's not. The V developers have already hinted at using alternatives to the GC, for that remaining percentage, so memory safety without the GC is on the table for them.

Based on what I've read and hints dropped, can see them adding some type of additional DFA and borrow checker, somewhat like D, to be combined with autofree. Awareness of this possibility, might be why V's competitors have been so overly focused on them. As we are talking about combining it to an easier to use language, with cleaner syntax.

maleldil 12/22/2025||||
Oh, it's known. It just has an incredibly negative reputation on this site.
baranul 12/26/2025|||
This "negative reputation" on here, looks to be something that was first artificially generated by competitors and then allowed to boil, along with those using the bubbling to promote themselves and their sites.
freakynit 12/22/2025|||
I kinda expected.. just hesitated to point it out.
baranul 12/26/2025||||
Interesting, how various people don't feel you are entitled to your opinion about languages or the beauty of V, unless it is to "push" the negative.
gf000 12/23/2025|||
More like "mostly known from stating absolutely ridiculous claims", though I heard they went back on most of them and now are more realistic - but also much less interesting.
culebron21 12/22/2025||
I couldn't figure out the main points, besides the "between Rust & Go" slogan. I've worked both with Rust and Go, and I like Rust more, but there are several pain points:

* macro abuse. E.g. bitshift storing like in C needs a bunch of #[...] derive_macros. Clap also uses them too much, because a CLI parameter is more complex than a struct field. IDK what's a sane approach to fixing this, maybe like in Jai, or Zig? No idea.

* Rust's async causes lots of pain and side effects, Golang's channels seem better way and don't make colored functions

* Rust lacks Python's generators, which make very elegant code (although, hard to debug). I think if it gets implemented, it will have effects like async, where you can't keep a lock over an await statement.

Zig's way is just do things in the middle and be verbose. Sadly, its ecosystem is still small.

I'd like to see something attacking these problems.

resonious 12/22/2025||
I've been having fun with Gleam. I'm not really sure where it falls on the spectrum though. It is garbage collected, so it's less abrasive than Rust in that sense. But it's pure functional which is maybe another kind of unfriendly.
steveklabnik 12/22/2025||
Gleam is very cool! But yeah, higher level than I’m shooting for here.
steveklabnik 12/22/2025||
It’s too early to have slick marketing and main points.

Noted, thanks for the comment. I share some of these opinions more than others, but it’s always good to get input.

Panzerschrek 12/22/2025||
I am surprised that a language with nothing than a couple of promises gets so much attention. Why exactly?
steveklabnik 12/22/2025||
I've been a member of this community for a long time.

People also like hearing about new languages.

I agree that it's not really ready for this much attention just yet, but that's the way of the world. We'll see how it goes.

barnabee 12/22/2025|||
I think ~everyone wants a language that's kind of like Go with a Rusty type system (and maybe syntax), so any title like this gets attention.

There's an obvious sweet spot in there.

squirrellous 12/22/2025|||
IIRC the author has a good track record with programming languages.
forgotpwd16 12/22/2025||
One of which the implementation is 100% vibe coded even.
jameskilton 12/21/2025||
Probably best to link to the repo itself, this is not meant to be used yet. https://github.com/rue-language/rue
chrysoprace 12/22/2025||
It may have been more useful to link to the blog post [0] which gives more of an introduction than the front page at this point.

[0] https://rue-lang.dev/blog/hello-world/

steveklabnik 12/22/2025|
I posted that, and also https://steveklabnik.com/writing/thirteen-years-of-rust-and-...

Just to link them all together. This is the one that the algorithm picked up :)

oulipo2 12/21/2025||
Interesting, for me the "between Rust and Go" would be a nice fit for Swift or Zig. I've always quite liked the language design of Swift, it's bad that it didn't really take off that much
steveklabnik 12/21/2025||
One thing working on this project has already done is give me more appreciation for a lot of Zig's design.

Zig really aims to be great at things I don't imagine Rue being useful for, though. But there's lots of good stuff there.

And lots of respect to Swift as well, it and Hylo are also major inspiration for me here.

isodev 12/22/2025|||
I think with Swift 6 Apple really took it in a wrong direction. Even coding agents can’t wrap their mind around some of the “safety” features (not to mention the now bloated syntax). If anything, Swift would go down as a “good example why language design shouldn’t happen by committee in yearly iterations”.
vips7L 12/22/2025||
Checkout Borgo: https://github.com/borgo-lang/borgo

I also find that D is good between language. You can do high level or low level whenever you need it.

You can also do some inbetween systems programming in C# if you don’t care about a VM or msft.

behindsight 12/22/2025||
> You can also do some inbetween systems programming in C# if you don’t care about a VM or msft.

C# Native AOT gets rid of the JIT and gives you a pretty good perf+memory profile compared to the past.

It's mostly the stigma of .NET Framework legacy systems that put people off, but modern C# projects are a breeze.

vips7L 12/22/2025|||
AFAIK there’s still holes like reflection and you have some work, but if that’s changed that’s really good. I suspect it’ll be hard for C# to escape the stench of “enterprise” though.

I’m looking forward to seeing how it shapes out over the next few years. Especially once they release union types.

neonsunset 12/22/2025|||
FWIW JIT is rarely an issue, and enables strong optimizations not available in AOT (it has its own, but JIT is overall much better for throughput). RyuJIT can do the same speculative optimizations OpenJDK Hotspot does except the language has fewer abstractions which are cheaper and access to low-level programming which allows it to have much different performance profile.

NativeAOT's primary goal is reducing memory footprint, binary size, making "run many methods once or rarely" much faster (CLI and GUI applications, serverless functions) and also shipping to targets where JIT is not allowed or undesirable. It can also be used to ship native dynamically or statically (the latter is tricky) linked libraries.

lifis 12/21/2025||
All the Rue code in the manual seems to also be valid Rust code, except for the @-prefixed intrinsics
steveklabnik 12/21/2025|
Yes, I started off with the idea that Rue's syntax would be a strict subset of Rust's.

I may eventually diverge from this, but I like Rust's syntax overall, and I don't want to bikeshed syntax right now, I want to work on semantics + compiler internals. The core syntax of Rust is good enough right now.

scuff3d 12/22/2025|||
Out of interest, what's the motivation? What are you hoping to do with Rue that Rust doesn't currently provide?
steveklabnik 12/22/2025||
Primary motivation is to have a fun project. If nobody ever uses this, I'll still be happy.

I'd like fast compile times, and giving up some of Rust's lowest level and highest performance goals in exchange for it. As well as maybe ease of use.

scuff3d 12/22/2025||
Nice, seems like a super cool project.

I've thought a Rust like language but at Go's performance level would be interesting. Garbage collected, but compiled to a binary (no VM), but with Rust's mix of procedural and functional programming. Maybe some more capable type inference.

If you don't mind me asking, how did you get started with programming language design? I've been reading Crafting Interpreters, but there is clearly a lot of theory that is being left out there.

steveklabnik 12/22/2025||
Thanks :)

Crafting interpreters is fantastic!

Mostly just… using a lot of them. Trying as many as I could. Learning what perspectives they bring. Learning the names for their features, and how they fit together or come into tension.

The theory is great too, but starting off with just getting a wide overview of the practice is a great way to get situated and decide which rabbit holes you want to go down first.

scuff3d 12/22/2025||
> Mostly just… using a lot of them

Well I got that part covered at least. Seems like I'm constantly getting bored and playing around with a different language, probably more than I should lol

emerent 12/22/2025|||
How is it a subset then if it has the @-prefix? Wait, does Rust's grammar still have the @ and ~ sigils from the pre 1.0 times for pointers?
steveklabnik 12/22/2025||
It started off that way, but didn't (and won't) remain that way.

I'm using @ for intrinsics because that's how Zig does it and I like it for similar reasons to how Rust uses ! for macros.

Joker_vD 12/22/2025|
Okay, right now it's basically Pascal as it was described in Revised Report, only even more restricted. Which is... fine, I guess, you can still write a whole OS with something like that (without using pointers/addresses) as Per-Brinch Hansen demonstrated but it's... an acquired taste.

Are the actual references/pointers coming in the future?

steveklabnik 12/22/2025|
Maybe Pascal without the syntax, sure. It’s still very early on.

I hope to not introduce references, because I’m going to give mutable value semantics a go. We’ll see though!

More comments...