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Zig is a middle ground. It solves some of the common foot-guns in C, Without the costs of affine substructural typing that offers Rust its super powers.

I am of the opinion that it is horses for courses and not a universal better proposition.

Because my needs don’t fit in with Rust’s decisions very well I will use zig for personal projects when needed. I just need linked lists, graphs etc…

While hopefully someone can provide a more comprehensive explanation here are the two huge wins for my use case.

1) In Zig, accessing an array or slice out of bounds is considered detectable illegal behavior.

2) defer[0] allows you to collocate the the freeing of resources with code.

That at least ‘feels’ safer to me than a bunch of ‘unsafe’ rust that is required for my very specific use case.

I was working on some eBPF code in C and did really miss zig.

For me it fits the Pareto principle but zig is also just a sometimes food for me, so take that for what it is worth.

[0] https://zig.guide/language-basics/defer/

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Fwiw you don't need unsafe for graphs or linked lists in Rust. At least not directly - these things can be abstracted. The petgraph crate is the most popular for graphs. I'm not sure about linked lists because linked lists are the wrong choice 99.9% of the time.

I've written hundreds of thousands of lines of Rust and outside of FFI, I've written I think one line of unsafe Rust.

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It's not as simple as that. All software is abstraction and with any software if you go deep enough you'll find unsafe code.

E.g. look at a Python list. Is it safe? In Python sure, but that's abstracting a C implementation which definitely isn't safe.

If you look at Rust's std::Vec you'll find a very similar story - safe interface over an unsafe implementation.

It isn't as binary as you think.

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Not really though. That's like saying that no language is "safe" because the compiler could have a bug.

It's true that safe wrappers around unsafe code sometimes have bugs in them, but it's orders of magnitude easier to get the abstraction right once than to use unsafe correctly in many places sprawled across a large codebase.

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If you don’t see any difference between those two, I’m really not sure what to say.
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Show code
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I think he meant "show me a true linked list / node graph in rust that isn't unsafe". The reason being its not possible using c-style pointer following (or without just putting everything auto-pointers). What you've shown is exactly the tradeoff they were referring to. In rust, the answer is: make sure lifetime of all memory is explicitly managed, then use integers for the 'links' between nodes.

His point was that for his programming, he wants to be able to make real pointers and real linked lists with memory unsafe, which Rust makes difficult or opaque. For example with linked list, you could simulate (to avoid unsafe), by either boxing everything (so all refs are actually smart pointers), or you can use a container with scoped memory lifetime, and have integers in an array that are the "next" pointer. In addition to extra complexity, the "integers as edges" doesn't actually solve the complexity, it just means you can't get a bad memory error (you can still have 'pointers' that point to the wrong index if you're rolling your own).

Same with your graph code. Using a COO representation for a graph does in theory make it "memory safe" (albeit more clumsy to use if you are doing pointer-following logic), and it also introduces other subtle bugs if your logic is wrong (e.g. you have edge 100 but actually those nodes were removed, so now you're pointing at the wrong node).

I think the point (which I agree with for things like linked list, graph, compiler) is that depending on your usecase, the "safety" guarantees of rust are just making it harder to write the simplest most understandable code. Now instead of: `Node* next` I have lifetimes, integer references, two collections (nodes and edges) to keep in sync, smart pointers, etc. Previously my complexity was to make sure `next != null`, now its a ton of boilerplate and abstractions, performance hits, or more subtle bugs (like 'next' indices getting out of sync with the array of 'nodes').

If there was a way to explicitly track the lifetime of an arbitrary graph/tree of pointers at compile time, we wouldn't need garbage collection -- its not solvable at compile time, and the complexity has to live somewhere.

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Err https://github.com/petgraph/petgraph

What are you asking for exactly?

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Forgive me if I've mis-understood this thread, but there are unsafe declerations in that crate. Is there really any difference between using unsafe in your own code, versus wrapping it inside some crate?

I guess you are making the point that the user does not have to concern themselves with the unsafe declarations?

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I don't think it's unreasonable, even though I am getting marked down for daring to ask, for people who are making assertions, even if they are well understood *within their own community* (that is, not necessarily universally known) to show examples of what they are talking about.

You're correcting someone, so it's clear that your understanding isn't universal, and example code is the absolute minimum.

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It doesn't seem clear what code you're asking for.
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Zig doesn't even have RAII...
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which is a good thing. C++'s RAII is magic-sauce that does a lot for you when you can simply use `defer` in zig. A constructor is just a function call. A destructor is just a function call.
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And a function call is just a fancy JMP, still it's generally acknowledged to be better to have all the bookkeeping automated.
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Does defer in zig track the objects lifetime directly, or is it like the various other 'context' features in other languages where it only really works for lifetimes of function-local variables and leaves you on your own when things get more complicated? (which, IMO, is precisely when RAII becomes most useful. It does seem like most of these languages only consider the 'forgetting to cleanup on an early return from a function' case)
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Constructors and destructors are also just function calls in C++

And you can't forget to type defer

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How is defer not magic sauce?
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Whether you consider it magic is up to you, but, unlike a destructor in RAII, there is nothing automatic going on. If you don't explicitly invoke a destructor, you won't get a destructor.

The fact that you can explicitly invoke the destructor to happen later is simply syntactic sugar, just like if/else/while, or any other control construct more powerful than a conditional jump instruction.

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And more importantly, you can choose what destructor to call. This is perhaps what's most underrated about defer, because defer can select among many different destructors possible, at multiple different levels (group free with arenas, individual free, etc).
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> If you don't explicitly invoke a destructor, you won't get a destructor.

When you explicitly invoke a "destructor", you do it on many code paths (and miss one or two)

>The fact that you can explicitly invoke the destructor to happen later

You don't specify where the `defer`-red "destructor" will be invoked.

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zig is unmanaged memory. But rust also allows memory leaks, and they're not uncommon in large, complex programs. So this rewrite will not necessarily control for that.
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What language doesn't allow memory leaks?
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There are two kinds of memory leaks: forgotten manual freeing (all references are gone, but allocation is not) and forgetting to get rid of references that keeps an allocation alive. Both are a kind of logical error, but the first is mostly possible in languages with manual memory management. The second one is a universal logical error (only programmer knows which live references are really needed).
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Rust allows reference-counting cycles, right?
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Nope! Zig is like C in this regard. There’s no borrow checker. Managing memory is your responsibility.

It gives you a few more tools than C - like a debug allocator, bounds checked array slices and so on. But it’s not a memory safe language like rust.

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It's not.. but im pretty sure it could be. could probably even take this (WIP) idea and bolt on a formal verifier pretty easily.

https://github.com/ityonemo/clr

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It'd take more than that to match rust's borrow checker. Rust's borrow checker tracks lifetimes, and sometimes needs annotations in code to help it understand what you're actually trying to do. I suppose you could work around that by adding lifetime annotations in zig comments. Then you've have a language that's a lot like rust, but without an ecosystem of borrowck-safe libraries. And with worse ergonomics (rust knows when it can Drop). And rust can put noalias everywhere in emitted code. And you'd probably have worse error messages than the rust compiler emits.

Its an interesting idea. But if you want static memory safety in a low level systems language, its probably much easier to just use rust.

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> I suppose you could work around that by adding lifetime annotations in zig comments.

you can make a no-op function that gets compiled out but survives AIR

> rust knows when it can Drop.

and its possible to cause problems if you aren't aware where rust picks to dropp.

> And rust can put noalias everywhere in emitted code.

zig has noalias and it should be posssible to do alias tracking as a refinement.

> But if you want static memory safety in a low level systems language, its probably much easier to just use rust.

don't use that attitude to suck oxygen out of the air. rust comes with its own baggage, so "just using rust because its the only choice" keeps you in a local minimum.

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> and its possible to cause problems if you aren't aware where rust picks to drop.

Can you give some examples? I've never ran into problems due to this.

> don't use that attitude to suck oxygen out of the air. rust comes with its own baggage

Yeah, that's a totally fair argument. One nice aspect of the approach you're proposing is it'd give you the opportunity to explore more of the borrow checker design space. I'm convinced there's a giant forest of different ways we could do compile time memory safety. Rust has gone down one particular road in that forest. But there's probably loads of other options that nobody has tried yet. Some of them will probably be better than rust - but nobody has thought them through yet.

I wish you luck in your project! If you land somewhere interesting, I hope you write it up.

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> Can you give some examples? I've never ran into problems due to this.

If it's doing a drop in the hot loop that may be an unexpected performance regression that could be carefully lifted.

thank you. Unfortunately in the last few weeks i've been too busy with my startup to put as much work into it. We'll see =D

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> If it's doing a drop in the hot loop that may be an unexpected performance regression that could be carefully lifted.

Yeah, I've heard of people being surprised that when they make massive collections of Box'ed entries, then get surprised that it takes a long time to Drop the whole thing. But this would be the same in C or Zig too. Malloc and free are really complex functions. Reducing heap allocations is an essential tool for optimisation.

The solution to this "unexpected performance regression" in rust is the same as it is in C, C++ and Zig: Stop heap allocating so much. Use primitive types, SSO types (SmartString and friends in rust) or memory arenas. Drop isn't the problem.

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In zig the solution is to use an arena allocator. That’s about as easy as it gets. Maybe Rust also allows doing that, I don’t know.
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You can use arenas in Rust, it's just not as trivial to swap allocators generally. But there are plenty of crates for it.
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It is quite obvious that Zig is pre 1.0 with thousands of stranded unsolved issues (per their GitHub repo). A review of Zig hype gives the strong impression it was created by being relentlessly and suspiciously pushed on HN, beyond logic or its language rankings (per TIOBE or GitHub stats), so that many were under the illusion that the language was something more or other than what it really is.

Zig is still under development and beta. Stability, crashes, and leaks should not be surprising, and even expected. To stick with a beta language, usually companies and developers are philosophically and/or financially aligned with the language. An example is JangaFX and Odin, where they not only have committed to using the language (despite being beta) in their products, but have directly hired GingerBill.

Team Bun appears to have "alignment and relationship issues" with Zig, to the point they have decided to extensively explore their options. Now Bun is rewritten in Rust. They are seeing if Rust solves their requirements. As with any relationship, if one ignores or takes a partner for granted, don't be surprised if they want a divorce or jump to someone else.

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You might want to check their Codeberg then, because they've moved all their development over there...
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Zig very much could of moved all of their GitHub issues over to Codeberg, to be resolved, but chose not to do so. Thus left thousands of issues unsolved and stranded.

This maneuver was arguably obfuscated by the anti-LLM stance and finger pointing at Microsoft, but nevertheless, many still have noticed. Zig, for a long time, had been falling behind and doing poorly on their open to close ratio for resolving issues. It should be embarrassing to leave so many issues open.

Even if not accepting new GitHub issues, they have demonstrated an inability to resolve existing issues, except at an extremely slow pace. Considering there are just about no new issues on their GitHub repo, it is understandable if there are those that find the pace to close and amount of issues unacceptable or questionable, in addition to the clearly bad open to close ratio.

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Did you read their migration post? They are thinking about it as COW, so they're using both issue trackers right now, but as soon as the update an issue it jumps straight to the Codeberg issue tracker. It's an unconventional way of doing it, but it's no conspiracy.
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