"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"
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.
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
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.
> 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.
> 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.
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.
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.
> 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.
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.
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.
> 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.
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.
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.
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!
> 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.
> 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
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?
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. :)
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.
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.
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.
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.
> 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.
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.
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.
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?
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.
> 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.
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.
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.
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.
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.
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
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”.
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?
i see a lot of go hatred on HN but coming from c i actually kind of love go when i need just enough abstracted away from me to focus on doing a thing efficiently and still end up with a well-enough performing binary. i have always been obsessed with the possibility of building something that doesn't need me to install runtimes on the target i want to run it, it's just something that makes me happy. very rarely do i need to go lower than what go provides and when i do i just.. dip into c where i earned a lot of my stripes over the years.
rust is cool. a lot of really cool software im finding these days is written in rust these days & i know im missing some kind of proverbial boat here. but rusts syntax breaks my brain and makes it eject completely. it's just enough to feel like it requires paradigm shifts for me, and while others are really good at hopping between many languages it's just a massive weakness of mine. i just cant quite figure out the ergonomics of rust so that it feels comfy, my brain seems to process everything through a c-lens and this is just a flaw of mine that makes me weak in software.
golang was started by some really notable brains who had lots of time in the game and a lot of well thought out philosophies of what could be done differently and why they should do it differently coming from c. there was almost a socio-economic reason for the creation of go - provide a lang that people could easily get going in and become marketable contributors that would help their career prospects. and i think it meets that mark, i was able to get my jr engineers having fun in golang in no time at all & that's panned out to be a huge capability we added to what our team can offer.
i like the objective of rue here. reviewing the specification it actually looks like something my brain doesn't have any qualms with. but i dont know what takes a language from a proposal by one guy and amplifies it into something thats widely used with a great ecosystem. other minds joining to contribute & flesh out standard libraries, foundations backing, lots of evangelism. lots of time. i won't write any of those possibilities off right now, hopefully if it does something right here there's a bright future for it. sometimes convincing people to try a new stack is like asking them to cede their windows operating system and try out linux or mac. we've watched a lot of languages come and go, we watch a lot of languages still try to punch thru their ceilings of general acceptance. unlike some i dont really have huge tribalistic convictions of winners in software, i like having options. i think it's pretty damn neat that folks are using their experiences with other languages to come up with strong-enough opinions of how a language should look and behave and then.. going out and building it.
I am very interested in Hylo! I think they're playing in similar spaces. I'd like to explore mutable value semantics for Rue.
One huge difference is that Hylo is using LLVM, whereas I'm implementing my own backends. Another is that Hylo seems to know what they want to do with concurrency, whereas I really do not at all right now.
I think Hylo takes a lot of inspiration from Swift, whereas I take more inspiration from Rust. Swift and Rust are already very similar. So maybe Hylo and Rue will end up like this: sister languages. Or maybe they'll end up differently. I'm not sure! I'm just playing around right now.
That’s part of the reason for the name! “Rust” also has negative interpretations as well. A “rue” is also a kind of flower, and a “rust” is a kind of fungus.
Fair enough! I do like how others are framing this is as "write less code" -- if Rue makes one think more and more about the code that finally makes it to the production, that can be a real win.
I have mostly been writing Rust in the last 10 years, but recently (1 year) I have been writing Go as well as Rust.
The typical Go story is to use a bunch of auto generation, so a small change quickly blows up as all of the auto generate code is checked into git. Like easily a 20x blowup.
Rust on the other hand probably does much more such code generation (build.rs for stuff like bindgen, macros for stuff like serde, and monomorphized generics for basically everything). But all of this code is never checked into git (with the exception of some build.rs tools which can be configured to run as commands as well), or at least 99% of the time it's not.
This difference has impact on the developer story. In go land, you need to manually invoke the auto generator and it's easy to forget until CI reminds you. The auto generator is usually quite slow, and probably has much less caching smartness than the Rust people have figured out.
In Rust land, the auto generation can, worst case, run at every build, best case the many cache systems take care of it (cargo level, rustc level). But still, everyone who does a git pull has to re-run this, while with the auto generation one can theoretically only have the folks run it who actually made changes that changed the auto generated code, everyone else gets it via git pull.
So in Go, your IDE is ready to go immediately after git pull and doesn't have to compile a tree of hundreds of dependencies. Go IDEs and compilers are so fast, it's almost like cheating from Rust POV. Rust IDEs are not as fast at all even if everything is cached, and in the worst case you have to wait a long long time.
On the other hand, these auto generation tools in Go are only somewhat standardized, you don't have a central tool that takes care of things (or at least I'm not aware of it). In Rust land, cargo creates some level of standardization.
You can always look at the auto generated Go code and understand it, while Rust's auto generated code usually is not IDE inspectable and needs special tools for access (except for the build.rs generated stuff which is usually put inside the target directory).
I wonder how a language that is designed from scratch would approach auto generation.
> On the other hand, these auto generation tools in Go are only somewhat standardized, you don't have a central tool that takes care of things (or at least I'm not aware of it).
Yeah, this is a hard problem, and you're right that both have upsides and downsides. Metaprogramming isn't easy!
I know I don't want to have macros if I can avoid them, but I also don't forsee making code generation a-la-Go a first class thing. I'll figure it out.
> The typical Go story is to use a bunch of auto generation, so a small change quickly blows up as all of the auto generate code is checked into git. Like easily a 20x blowup.
Why do you think the typical Go story is to use a bunch of auto generation? This does not match my experience with the language at all. Most Go projects I've worked on, or looked at, have used little or no code generation.
I'm sure there are projects out there with a "bunch" of it, but I don't think they are "typical".
Same here. I've worked on one project that used code generation to implement a DSL, but that would have been the same in any implementation language, it was basically transpiring. And protobufs, of course, but again, that's true in all languages.
The only thing I can think of that Go uses a lot of generation for that other languages have other solutions for is mocks. But in many languages the solution is "write the mocks by hand", so that's hardly fair.
Me neither. My go code doesn't have any auto-generation. IMO it should be used sparingly, in cases where you need a practically different language for expressivity and correctness, such as a parser-generator.
Anything and everything related to Kubernetes in Go uses code generation. It is overwhelmingly "typical" to the point of extreme eye-rolling when you need to issue "make generate" three dozen times a day for any medium sized PR that deals with k8s types.
The "just generate go code automatically then check it in" is a massive miswart from the language, and makes perfect sense because that pathological pattern is central to how google3 works.
A ton of google3 is generated, like output from javascript compilers, protobuf serialization/deserialization code, python/C++ wrappers, etc.
So its an established Google standard, which has tons of help from their CI/CD systems.
For everyone else, keeping checked-in auto-generated code is a continuous toil and maintenance burden. The Google go developers don't see it that way of course, because they are biased due to their google3 experience. Ditto monorepos. Ditto centralized package authorities for even private modules (my least fave feature of Go).
> For everyone else, keeping checked-in auto-generated code is a continuous toil and maintenance burden. The Google go developers don't see it that way of course, because they are biased due to their google3 experience.
The golang/go repo itself has various checked-in generated repo
When Go was launched, it was said it was built specifically for building network services. More often than not that means using protobuf, and as such protobuf generated code ends up being a significant part of your application. You'd have that problem in any language, theoretically, due to the design of protobuf's ecosystem.
Difference is that other languages are built for things other than network services, so protobuf is much less likely to be a necessary dependency for their codebases.
The positioning is interesting - claiming Rust's performance with Go's simplicity is basically every new systems language's promise since 2015. The key differentiator seems to be "zero-cost exceptions" which I assume means compile-time Result types without runtime unwinding overhead? That's compelling if true, since Rust's Result ergonomics can get verbose in deeply nested error chains.
But the real test is compile times and cognitive overhead. Rust's borrow checker is theoretically elegant but practically brutal when you're learning or debugging. If Rue can achieve memory safety without lifetime annotations everywhere, that's genuinely valuable. However, I'm skeptical - you can't eliminate tradeoffs, only move them around. If there's no borrow checker, what prevents use-after-free? If there's garbage collection, why claim "lower level than Go"?
The other critical factor is ecosystem maturity. Rust's pain is partially justified by its incredible crate ecosystem - tokio, serde, axum, etc. A new language needs either (1) seamless C FFI to bootstrap libraries, (2) a killer feature so valuable that people rewrite everything, or (3) 5+ years for the ecosystem to develop. Which path is Rue taking?
I'd love to see real-world benchmarks on: compile time for a 50k line project, memory usage of a long-running web server compared to Rust/Go, and cold start latency for CLI tools. Those metrics matter more than theoretical performance claims. The "fun to write" claim is subjective but important - if it's genuinely more ergonomic than Rust without sacrificing performance, that could attract the "Python developers wanting systems programming" demographic.
Your style of commenting is pretty full of LLM tells fyi. Normally don’t comment on it but this is the second such comment of yours I have read in a few minutes.
e: I would be curious of the thoughts of those downvoting as personally I don’t think mostly LLM written comments are a direction we want to move towards on HN.
Rather than downvoting you, I will speak up to say I don't see what you're seeing. Spaces around hyphens, yeah, sure, but LLMs prefer em dashes, and even that is unreliable, because it's borrowed from habits that real humans have had for many years.
For me, the more important indicator is the content. I see reports of personal experience, and thoughts that are not completely explained (because the reader is expected to draw the rest of the owl). I don't see smugly over-the-top piles of adjectives filling in for an inability to make critiques of any substance. I don't see wacky asides amounting to argumentum ad lapidem, accomplishing nothing beyond insulting readers who disagree with a baseless assertion.
I think it's likely you have drawn a false positive.
A) you cannot tell
B) you have said nothing productive toward discussion, you’ve just accused someone of using a tool (that you don’t know if they used)
I’d prefer actual criticism of the content. (I cannot downvote and would not if I could)
I write a lot of go. I tried to write a lot of rust but fell into lifetime traps. I really want to leave C++ but I just can’t without something that’s also object oriented.
Not a dig at functional, it’s just my big codebases are logically defined as objects and systems that don’t lend itself to just being a struct or an interface.
Inheritance is why I’m stuck in C++ land.
I would love to have something like rust but that supports classes, virtual methods, etc. but I guess I’ll keep waiting.
In Rust you can have structs with any number of methods defined on them, which is functionally not that different from a class. You get interface like behavior with traitsz and you get encapsulation with private/public data and methods.
Yes it does. Unless I can attach a trait to a struct without having to define all the methods of that trait for that struct. This is my issue with interfaces and go. I can totally separate out objects as interfaces but then I have to implement each implementation’s interface methods and it’s a serious chore when they’re always the same.
For example: Playable could be a trait that plays a sound when you interact with it. I would need to implement func interact for each object. Piano, jukebox, doorbell, etc. With inheritance, I write it once, add it to my class, and now all instances of that object have interact. Can I add instance variables to a trait?
This saves me time and keeps Claude out of my code. Otherwise I ask Claude to implement them all, modify them all, to try to keep them all logically the same.
I also don’t want to go type soup in order to abstract this into something workable.
I respect your preferences, but I am unlikely to add this sort of OOP. Ideally there'll be no subtyping at all in Rue. So you'll have to keep waiting, I'm afraid. Thanks for checking it out regardless!
As a long time C++ user, I’m curious why you like inheritance and virtual methods so much.
I maintain a medium sized, old-ish C++ code base. It uses classes and inheritance and virtual methods and even some multiple inheritance. I despise this stuff. Single Inheritance is great until you discover that you have a thing that doesn’t slot nicely into the hierarchy or when you realize that you want to decompose an interface (cough, base class) into a couple of non-hierarchically related things. Multiple inheritance is an absolute mess unless you strictly use base classes with pure virtual methods and no member variables. And forcing everything into an “is a” relationship instead of a “has a” relationship can be messy sometimes.
I often wish C++ had traits / or Haskell style type classes.
Protected and private inheritance are C++'s equivalent to traits, and they don't suffer from the usual issues of multiple inheritance. As for type classes, check out concepts. By no means am I trying to sell C++, I don't touch it myself, but it doesn't leave you completely adrift in those seas.
So, one reason is "I just want to learn more about buck2."
But, for the first iteration of Rue, I maintained both. However, for a language project, there's one reason Cargo isn't sufficient now, and one reason why it may not later: the first one is https://github.com/rue-language/rue/blob/trunk/crates/rue-co... : I need to make sure that, no matter what configuration I build the compiler in, I build a staticlib for the runtime. With Cargo, I couldn't figure out how to do this. In test mode, it would still try to build it as a dylib.
Later, well, the reason that rustc has to layer a build system on top of Cargo: bootstrapping. I'm not sure if Rue will ever be bootstrapped, but rustc uses x.py for this. Buck does it a lot nicer, IMHO https://github.com/dtolnay/buck2-rustc-bootstrap
Anything out there for reference or would you be implementing from theory/ideas here? God speed to you in terms of the project overall, it's exciting to see the beginnings of a rust-like-lang without the headaches!
I landed non-generic enums this evening. I'm not 100% sure what abstraction paths I want to go down. But I see sum types as just as important as product types, for sure.
I wince every time I see naive recursive fibonacci as a code example. It is a major turnoff because it hints at a lack of experience with tail call optimization, which I consider a must have for a serious language.
Would someone please explain to me why TCO—seemingly alone amongst the gajillions of optimization passes performed by modern compilers—is so singularly important to some people?
For people that like functional style and using recursion for everything, TCO is a must. Otherwise there’s no way around imperative loops if you want decent performance and not having to worry about the stack limit.
Perhaps calling it an “optimization” is misleading. Certainly it makes code faster, but more importantly it’s syntax sugar to translate recursion into loops.
TCO is less of an optimization (which are typically best-effort on the part of the compiler) and more of an actual semantic change that expands the set of valid programs. It's like a new control flow construct that lives alongside `while` loops.
When you have recursive data structures, it's nice when the algorithms have the same shape. TCO is also handy when you're writing fancy control flow operations and implement them with continuation-passing style.
It virtue-signals that they're part of the hip functional crowd.
(To be fair, if you are programming functionally, it is essential. But to flat-out state that a language that doesn't support isn't "serious" is a bit rude, at best.)
I only have basic constant folding yet in terms of optimizations, but I'm very aware of TCO. I haven't decided if I want to require an annotation to guarantee it like Rust is going to.
Please require some form of annotation like an explicit `tailcall` operator or something similar. TCO wrecks havoc on actionable backtraces, so it should be opt-in rather than opt-out.
This is a bit silly but when i look at new languages coming up I always look at the syntax, which is usually horrible(Zig and Rust are good examples), and how much garbage there is. As someone that writes in Go, I can't stand semicolons and other crap that just pollutes the code and wastes time and space to write for absolutely no good reason whatsoever. And as this compares itself with Go, I just cannot but laugh when I see ";", "->" or ":" in the example. At least the semicolon seems optional. But still, it's an instant nope for me.
The (n: i32) can be just (n i32), because there is no benefit to adding the colon there.
The -> i32 can also be just i32 because, again, the -> serves no purpose in function/method definition syntax.
So you end up with simple and clean
fn fib(n i32) i32 {}
And semicolons are an ancient relic that has been passed on to new languages for 80 fucking years without any good reason. We have modern lexers/tokenizers and compilers that can handle if you don't put a stupid ; at the end of every single effing line.
Just go and count how many of these useless characters are in your codebase and imagine how many keystrokes, compilation errors and wasted time it cost you, whilst providing zero value in return.
"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"
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.
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
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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.
> 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.
> 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.
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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.
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.
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.
> 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.
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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.
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.
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> 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.
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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.
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.
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!
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Wow didn't realise it was you who was the author. I learnt a lot about Rust from your writings.
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> 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]:
0 - https://dlang.org/
1 - https://ocaml.org/
2 - https://rue-lang.dev/
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Since it's framed as 'in between' Rust and Go, is it trying to target an intersection of both languages' use-cases?
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> 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
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.
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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?
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Is this a simplified / distilled version of Rust ? Or Subset of Rust with some changes ?
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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. :)
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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
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.
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.
C pointers expose CPU capabilities.
You can always emulate functionality on different architectures, though, so where is the practical line even drawn?
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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.
C was designed as a high level language and stayed so for decades
> 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.
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Go has a GC and Rust doesn't. That alone makes Go higher level.
> 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?
I am playing around with this! I'm mostly interested in something in the space of linear types + mutable value semantics.
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.
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You might find one of my late brother's research interests relevant: https://www.cs.princeton.edu/~dpw/papers/space.pdf
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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.
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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?
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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.
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So linear type + mutable value would be quite close to Rust, right?
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ARC is GC, chapter 5.
https://gchandbook.org/
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.
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Check out V-lang ... it has the details. It's a beautiful language... but, mostly unknown.
> 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...
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Oh, it's known. It just has an incredibly negative reputation on this site.
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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.
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.
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.
Gleam is very cool! But yeah, higher level than I’m shooting for here.
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.
I am surprised that a language with nothing than a couple of promises gets so much attention. Why exactly?
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.
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.
IIRC the author has a good track record with programming languages.
One of which the implementation is 100% vibe coded even.
Probably best to link to the repo itself, this is not meant to be used yet. https://github.com/rue-language/rue
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/
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 :)
All the Rue code in the manual seems to also be valid Rust code, except for the @-prefixed intrinsics
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.
Out of interest, what's the motivation? What are you hoping to do with Rue that Rust doesn't currently provide?
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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?
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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
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.
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”.
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.
> 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.
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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?
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!
I don't need lower level than go. I just really like Rust' type system and error handling and I want it in a compiled language.
Zero Cost abstractions and it's memory model is fascinating - but isn't particularly useful for the part of the tech stack I work on.
i see a lot of go hatred on HN but coming from c i actually kind of love go when i need just enough abstracted away from me to focus on doing a thing efficiently and still end up with a well-enough performing binary. i have always been obsessed with the possibility of building something that doesn't need me to install runtimes on the target i want to run it, it's just something that makes me happy. very rarely do i need to go lower than what go provides and when i do i just.. dip into c where i earned a lot of my stripes over the years.
rust is cool. a lot of really cool software im finding these days is written in rust these days & i know im missing some kind of proverbial boat here. but rusts syntax breaks my brain and makes it eject completely. it's just enough to feel like it requires paradigm shifts for me, and while others are really good at hopping between many languages it's just a massive weakness of mine. i just cant quite figure out the ergonomics of rust so that it feels comfy, my brain seems to process everything through a c-lens and this is just a flaw of mine that makes me weak in software.
golang was started by some really notable brains who had lots of time in the game and a lot of well thought out philosophies of what could be done differently and why they should do it differently coming from c. there was almost a socio-economic reason for the creation of go - provide a lang that people could easily get going in and become marketable contributors that would help their career prospects. and i think it meets that mark, i was able to get my jr engineers having fun in golang in no time at all & that's panned out to be a huge capability we added to what our team can offer.
i like the objective of rue here. reviewing the specification it actually looks like something my brain doesn't have any qualms with. but i dont know what takes a language from a proposal by one guy and amplifies it into something thats widely used with a great ecosystem. other minds joining to contribute & flesh out standard libraries, foundations backing, lots of evangelism. lots of time. i won't write any of those possibilities off right now, hopefully if it does something right here there's a bright future for it. sometimes convincing people to try a new stack is like asking them to cede their windows operating system and try out linux or mac. we've watched a lot of languages come and go, we watch a lot of languages still try to punch thru their ceilings of general acceptance. unlike some i dont really have huge tribalistic convictions of winners in software, i like having options. i think it's pretty damn neat that folks are using their experiences with other languages to come up with strong-enough opinions of how a language should look and behave and then.. going out and building it.
How does this differ from Hylo [0]?
[0] https://hylo-lang.org
I am very interested in Hylo! I think they're playing in similar spaces. I'd like to explore mutable value semantics for Rue.
One huge difference is that Hylo is using LLVM, whereas I'm implementing my own backends. Another is that Hylo seems to know what they want to do with concurrency, whereas I really do not at all right now.
I think Hylo takes a lot of inspiration from Swift, whereas I take more inspiration from Rust. Swift and Rust are already very similar. So maybe Hylo and Rue will end up like this: sister languages. Or maybe they'll end up differently. I'm not sure! I'm just playing around right now.
How are Swift and Rust very similar? I can search, but want to hear your opinion.
And congrats on starting a language project, even if Just for Fun (Linux). ;)
https://frappe.io/blog/book-reviews/just-for-fun-a-book-on-l...
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Just pointing out here that "rue" is used to express "to regret", emphatically. Perhaps it is not the best name for a programming language.
That’s part of the reason for the name! “Rust” also has negative interpretations as well. A “rue” is also a kind of flower, and a “rust” is a kind of fungus.
Fair enough! I do like how others are framing this is as "write less code" -- if Rue makes one think more and more about the code that finally makes it to the production, that can be a real win.
Sounds fitting to me. Every line of code I wrote that ultimately didn't need code to begin with, is basically codified regrets checked into git.
The best code is the code not written, so perhaps it is the best name for a programming language?
I have mostly been writing Rust in the last 10 years, but recently (1 year) I have been writing Go as well as Rust.
The typical Go story is to use a bunch of auto generation, so a small change quickly blows up as all of the auto generate code is checked into git. Like easily a 20x blowup.
Rust on the other hand probably does much more such code generation (build.rs for stuff like bindgen, macros for stuff like serde, and monomorphized generics for basically everything). But all of this code is never checked into git (with the exception of some build.rs tools which can be configured to run as commands as well), or at least 99% of the time it's not.
This difference has impact on the developer story. In go land, you need to manually invoke the auto generator and it's easy to forget until CI reminds you. The auto generator is usually quite slow, and probably has much less caching smartness than the Rust people have figured out.
In Rust land, the auto generation can, worst case, run at every build, best case the many cache systems take care of it (cargo level, rustc level). But still, everyone who does a git pull has to re-run this, while with the auto generation one can theoretically only have the folks run it who actually made changes that changed the auto generated code, everyone else gets it via git pull.
So in Go, your IDE is ready to go immediately after git pull and doesn't have to compile a tree of hundreds of dependencies. Go IDEs and compilers are so fast, it's almost like cheating from Rust POV. Rust IDEs are not as fast at all even if everything is cached, and in the worst case you have to wait a long long time.
On the other hand, these auto generation tools in Go are only somewhat standardized, you don't have a central tool that takes care of things (or at least I'm not aware of it). In Rust land, cargo creates some level of standardization.
You can always look at the auto generated Go code and understand it, while Rust's auto generated code usually is not IDE inspectable and needs special tools for access (except for the build.rs generated stuff which is usually put inside the target directory).
I wonder how a language that is designed from scratch would approach auto generation.
> On the other hand, these auto generation tools in Go are only somewhat standardized, you don't have a central tool that takes care of things (or at least I'm not aware of it).
https://pkg.go.dev/cmd/go#hdr-Generate_Go_files_by_processin...
FYI rust-analyzer can show expanded macros. It's not perfect because you only get syntax highlighting, but it works.
Yeah, this is a hard problem, and you're right that both have upsides and downsides. Metaprogramming isn't easy!
I know I don't want to have macros if I can avoid them, but I also don't forsee making code generation a-la-Go a first class thing. I'll figure it out.
> The typical Go story is to use a bunch of auto generation, so a small change quickly blows up as all of the auto generate code is checked into git. Like easily a 20x blowup.
Why do you think the typical Go story is to use a bunch of auto generation? This does not match my experience with the language at all. Most Go projects I've worked on, or looked at, have used little or no code generation.
I'm sure there are projects out there with a "bunch" of it, but I don't think they are "typical".
Same here. I've worked on one project that used code generation to implement a DSL, but that would have been the same in any implementation language, it was basically transpiring. And protobufs, of course, but again, that's true in all languages.
The only thing I can think of that Go uses a lot of generation for that other languages have other solutions for is mocks. But in many languages the solution is "write the mocks by hand", so that's hardly fair.
Me neither. My go code doesn't have any auto-generation. IMO it should be used sparingly, in cases where you need a practically different language for expressivity and correctness, such as a parser-generator.
Anything and everything related to Kubernetes in Go uses code generation. It is overwhelmingly "typical" to the point of extreme eye-rolling when you need to issue "make generate" three dozen times a day for any medium sized PR that deals with k8s types.
The "just generate go code automatically then check it in" is a massive miswart from the language, and makes perfect sense because that pathological pattern is central to how google3 works.
A ton of google3 is generated, like output from javascript compilers, protobuf serialization/deserialization code, python/C++ wrappers, etc.
So its an established Google standard, which has tons of help from their CI/CD systems.
For everyone else, keeping checked-in auto-generated code is a continuous toil and maintenance burden. The Google go developers don't see it that way of course, because they are biased due to their google3 experience. Ditto monorepos. Ditto centralized package authorities for even private modules (my least fave feature of Go).
> For everyone else, keeping checked-in auto-generated code is a continuous toil and maintenance burden. The Google go developers don't see it that way of course, because they are biased due to their google3 experience.
The golang/go repo itself has various checked-in generated repo
Auto generation? If you need to use that a lot, then the programming language is defective, I would say.
When Go was launched, it was said it was built specifically for building network services. More often than not that means using protobuf, and as such protobuf generated code ends up being a significant part of your application. You'd have that problem in any language, theoretically, due to the design of protobuf's ecosystem.
Difference is that other languages are built for things other than network services, so protobuf is much less likely to be a necessary dependency for their codebases.
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The positioning is interesting - claiming Rust's performance with Go's simplicity is basically every new systems language's promise since 2015. The key differentiator seems to be "zero-cost exceptions" which I assume means compile-time Result types without runtime unwinding overhead? That's compelling if true, since Rust's Result ergonomics can get verbose in deeply nested error chains.
But the real test is compile times and cognitive overhead. Rust's borrow checker is theoretically elegant but practically brutal when you're learning or debugging. If Rue can achieve memory safety without lifetime annotations everywhere, that's genuinely valuable. However, I'm skeptical - you can't eliminate tradeoffs, only move them around. If there's no borrow checker, what prevents use-after-free? If there's garbage collection, why claim "lower level than Go"?
The other critical factor is ecosystem maturity. Rust's pain is partially justified by its incredible crate ecosystem - tokio, serde, axum, etc. A new language needs either (1) seamless C FFI to bootstrap libraries, (2) a killer feature so valuable that people rewrite everything, or (3) 5+ years for the ecosystem to develop. Which path is Rue taking?
I'd love to see real-world benchmarks on: compile time for a 50k line project, memory usage of a long-running web server compared to Rust/Go, and cold start latency for CLI tools. Those metrics matter more than theoretical performance claims. The "fun to write" claim is subjective but important - if it's genuinely more ergonomic than Rust without sacrificing performance, that could attract the "Python developers wanting systems programming" demographic.
I’m explicitly not claiming Rust’s performance. Rust will always be ahead here. I’m giving up some of that performance for other things.
I do agree that those benchmarks are important. Once I have enough language features to make such a thing meaningful, I’ll be tracking them.
Where did I write that it’s fun to write?
Your style of commenting is pretty full of LLM tells fyi. Normally don’t comment on it but this is the second such comment of yours I have read in a few minutes.
e: I would be curious of the thoughts of those downvoting as personally I don’t think mostly LLM written comments are a direction we want to move towards on HN.
Rather than downvoting you, I will speak up to say I don't see what you're seeing. Spaces around hyphens, yeah, sure, but LLMs prefer em dashes, and even that is unreliable, because it's borrowed from habits that real humans have had for many years.
For me, the more important indicator is the content. I see reports of personal experience, and thoughts that are not completely explained (because the reader is expected to draw the rest of the owl). I don't see smugly over-the-top piles of adjectives filling in for an inability to make critiques of any substance. I don't see wacky asides amounting to argumentum ad lapidem, accomplishing nothing beyond insulting readers who disagree with a baseless assertion.
I think it's likely you have drawn a false positive.
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A) you cannot tell B) you have said nothing productive toward discussion, you’ve just accused someone of using a tool (that you don’t know if they used)
I’d prefer actual criticism of the content. (I cannot downvote and would not if I could)
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I write a lot of go. I tried to write a lot of rust but fell into lifetime traps. I really want to leave C++ but I just can’t without something that’s also object oriented.
Not a dig at functional, it’s just my big codebases are logically defined as objects and systems that don’t lend itself to just being a struct or an interface.
Inheritance is why I’m stuck in C++ land.
I would love to have something like rust but that supports classes, virtual methods, etc. but I guess I’ll keep waiting.
In Rust you can have structs with any number of methods defined on them, which is functionally not that different from a class. You get interface like behavior with traitsz and you get encapsulation with private/public data and methods.
Does inheritance really matter that much?
Yes it does. Unless I can attach a trait to a struct without having to define all the methods of that trait for that struct. This is my issue with interfaces and go. I can totally separate out objects as interfaces but then I have to implement each implementation’s interface methods and it’s a serious chore when they’re always the same.
For example: Playable could be a trait that plays a sound when you interact with it. I would need to implement func interact for each object. Piano, jukebox, doorbell, etc. With inheritance, I write it once, add it to my class, and now all instances of that object have interact. Can I add instance variables to a trait?
This saves me time and keeps Claude out of my code. Otherwise I ask Claude to implement them all, modify them all, to try to keep them all logically the same.
I also don’t want to go type soup in order to abstract this into something workable.
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I respect your preferences, but I am unlikely to add this sort of OOP. Ideally there'll be no subtyping at all in Rue. So you'll have to keep waiting, I'm afraid. Thanks for checking it out regardless!
As a long time C++ user, I’m curious why you like inheritance and virtual methods so much.
I maintain a medium sized, old-ish C++ code base. It uses classes and inheritance and virtual methods and even some multiple inheritance. I despise this stuff. Single Inheritance is great until you discover that you have a thing that doesn’t slot nicely into the hierarchy or when you realize that you want to decompose an interface (cough, base class) into a couple of non-hierarchically related things. Multiple inheritance is an absolute mess unless you strictly use base classes with pure virtual methods and no member variables. And forcing everything into an “is a” relationship instead of a “has a” relationship can be messy sometimes.
I often wish C++ had traits / or Haskell style type classes.
Protected and private inheritance are C++'s equivalent to traits, and they don't suffer from the usual issues of multiple inheritance. As for type classes, check out concepts. By no means am I trying to sell C++, I don't touch it myself, but it doesn't leave you completely adrift in those seas.
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Ah, yes, multiple inheritance in C++: where order matters but sanity does not
Usually it takes some time to get used to borrow checker and lifetimes. After that, you stop noticing them.
If this language is supposed to be used for systems programming, doing a factorial isn't really a selling example of why Rue.
For sure. It's just such early days I don't have a lot of stuff that's useful yet. I'll get there.
What the world needs is a more expressive language than Go, that interops with Go's compilation model and libraries.
Something like Borgo https://borgo-lang.github.io/
Sadly, seems to be abandoned. Last commit a year ago.
Nah, we already have that in D, C#, and who knows maybe one day Java finally gets Valhala, or one can use Kotlin or Scala in the meantime.
It's amazing how often C# (or more broadly CLR/JVM) is the pragmatic answer, even when you feel uncool using it.
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What was the rationale to not use cargo? By the way, I really enjoy when you are a guest on the fallthrough podcast.
Thanks!
So, one reason is "I just want to learn more about buck2."
But, for the first iteration of Rue, I maintained both. However, for a language project, there's one reason Cargo isn't sufficient now, and one reason why it may not later: the first one is https://github.com/rue-language/rue/blob/trunk/crates/rue-co... : I need to make sure that, no matter what configuration I build the compiler in, I build a staticlib for the runtime. With Cargo, I couldn't figure out how to do this. In test mode, it would still try to build it as a dylib.
Later, well, the reason that rustc has to layer a build system on top of Cargo: bootstrapping. I'm not sure if Rue will ever be bootstrapped, but rustc uses x.py for this. Buck does it a lot nicer, IMHO https://github.com/dtolnay/buck2-rustc-bootstrap
Any tentative ideas yet as to how you will manage the memory management? Sounds like a sort of magic 3rd way might be in the making/baking!
Something in the area of linear types and mutable value semantics.
Anything out there for reference or would you be implementing from theory/ideas here? God speed to you in terms of the project overall, it's exciting to see the beginnings of a rust-like-lang without the headaches!
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Any plans for adding algebraic data types (aka rust enums)?
I landed non-generic enums this evening. I'm not 100% sure what abstraction paths I want to go down. But I see sum types as just as important as product types, for sure.
Looks nice, but -> syntax always feels extremely off-putting. What does it get me?
I’m just copying Rust here because I care more about semantics at the moment. I may get rid of it, see some previous musings around this here https://steveklabnik.com/writing/too-many-words-about-rusts-...
In the intro text, the Ramsus is who ? a typo about php creator or a more obscure language creator?
It's a typo, I'm referring to https://en.wikipedia.org/wiki/Rasmus_Lerdorf. I'll fix it, thank you :)
How does it achieve memory safety?
Right now? By not even having heap allocation (though I'll be sending in the first PR for that soon.)
Eventually: through not having references, thanks to mutable value semantics. Also linear types.
But that's just ideas right now. It'll get there.
so unnecesary, just extra writing. We're developers, we understand that function return types are after first ()
No, no, copy Go here, i := 0 is just fine
I wince every time I see naive recursive fibonacci as a code example. It is a major turnoff because it hints at a lack of experience with tail call optimization, which I consider a must have for a serious language.
Would someone please explain to me why TCO—seemingly alone amongst the gajillions of optimization passes performed by modern compilers—is so singularly important to some people?
For people that like functional style and using recursion for everything, TCO is a must. Otherwise there’s no way around imperative loops if you want decent performance and not having to worry about the stack limit.
Perhaps calling it an “optimization” is misleading. Certainly it makes code faster, but more importantly it’s syntax sugar to translate recursion into loops.
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TCO is less of an optimization (which are typically best-effort on the part of the compiler) and more of an actual semantic change that expands the set of valid programs. It's like a new control flow construct that lives alongside `while` loops.
When you have recursive data structures, it's nice when the algorithms have the same shape. TCO is also handy when you're writing fancy control flow operations and implement them with continuation-passing style.
functional programming background / SICP ?
It virtue-signals that they're part of the hip functional crowd.
(To be fair, if you are programming functionally, it is essential. But to flat-out state that a language that doesn't support isn't "serious" is a bit rude, at best.)
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I only have basic constant folding yet in terms of optimizations, but I'm very aware of TCO. I haven't decided if I want to require an annotation to guarantee it like Rust is going to.
Please require some form of annotation like an explicit `tailcall` operator or something similar. TCO wrecks havoc on actionable backtraces, so it should be opt-in rather than opt-out.
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Plus we all know that fibs = 1 : 1 : zipWith (+) fibs (tail fibs) is the only serious Fibonacci implementation.
Who thunk of that one?
"Well you can judge the whole world on the sparkle that you think it lacks.
Yes, you can stare into the abyss, but it's staring right back"
Please, it supports a hole at best. Maybe a pit. No way will this let you construct an abyss.
How does this compare to Swift?
I don't plan on implementing ARC, I don't think. I do think Swift/Hylo mutable value semantics is a neat idea that I do want to play around with.
This is a bit silly but when i look at new languages coming up I always look at the syntax, which is usually horrible(Zig and Rust are good examples), and how much garbage there is. As someone that writes in Go, I can't stand semicolons and other crap that just pollutes the code and wastes time and space to write for absolutely no good reason whatsoever. And as this compares itself with Go, I just cannot but laugh when I see ";", "->" or ":" in the example. At least the semicolon seems optional. But still, it's an instant nope for me.
Weird, that's exactly how I feel reading Go:
}
And this one doesn't even have the infamous error-checking.
You cherry picked a contrived example but that's one of the cleanest generics implementations.
Now imagine if it had semicolons, ->, ! and '.
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I respect your preferences! I like punctuation.
Even though I have a Perl tattoo, it'll never get like that, though.
(Semicolon rules, for now at least, will be the same as Rust)
What would be better?
Remove all of that noise.
Take this:
The (n: i32) can be just (n i32), because there is no benefit to adding the colon there.
The -> i32 can also be just i32 because, again, the -> serves no purpose in function/method definition syntax.
So you end up with simple and clean fn fib(n i32) i32 {}
And semicolons are an ancient relic that has been passed on to new languages for 80 fucking years without any good reason. We have modern lexers/tokenizers and compilers that can handle if you don't put a stupid ; at the end of every single effing line.
Just go and count how many of these useless characters are in your codebase and imagine how many keystrokes, compilation errors and wasted time it cost you, whilst providing zero value in return.
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I wish more languages would adopt Clojure’s approach to optional delimiters in collections.
[2 45 78]
It’s just a nicer thing to view and type in my experience.
Regarding syntax soup, I think Odin is probably syntactically the cleanest of the lower level languages I’ve played with.
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when we are we getting a language that looks like python and runs 50 times faster than c++ /s