Would you mind sharing some thoughts about fil-c? AFAICT its claims mostly check out so besides implementation details (GC?) it seems directionally good.

▲ steveklabnik an hour ago | parent | next [-]

I'll come back and say some more in a bit, but in short: I like the idea of fil-c, but I also have some issues. I think it's overall a good and interesting project, but with some caveats.

▲ norman784 an hour ago | parent | prev | next [-]

Not OP, but AFAIK one big issue with FIL-C it does the checks at runtime, adding overhead, don't quote me on this, but IIRC is around 20% slower.

▲ steveklabnik 19 minutes ago | parent | prev [-]

Okay so: in general, as a rule of thumb: anything that makes stuff have more memory safety is good. And experiments towards that end are also good.

What I do not like, primarily comes down to how the project is talked about and marketed. First, because it promotes an "us vs them" mindset, instead of a "we're all trying to improve memory safety" mindset, and second, because in doing so, it also overstates its case.

These things are sort of intertwined. Let's talk about the overstatement first. Fil-c has its own definition of memory safety that is slightly different than others. For example, I saw this recently:

    #include <stdlib.h>
    #include <stdio.h>
    #include <string.h>
    
    struct User {
        char name[8];
        int is_root;
    };
    
    int main(int argc, char*argv[]) {
        struct User* user = malloc(sizeof(struct User));
        strcpy(user->name, argv[1]);
        if (user->is_root) {
            printf("I am root!\n");
        } else {
            printf("I am not root :(\n");
        }
        return 0;
    }

This, when invoked with "012345678" passed in, will print "I am root!". In my understanding, this is deliberately allowed.

But beyond corners like this, fil-c's author will go on about "Rust has unsafe as a hatch, fil-c does not" while if you control-f for "zunsafe_" on https://fil-c.org/stdfil you get ... escape hatches.

The author regularly erases the difference between "traps at runtime" and "is prevented at compile time", which are legitimate tradeoffs where one or the other may be better depending on what you're doing. But they're presented as either equivalent, or one is superior, and I find this muddles the discourse. The performance issues also tie into this, "add a GC" is absolutely a valid way to handle these sorts of issues, but it is not the same thing as what Rust does. And that's okay! But presenting it as purely superior means that it's just hard to talk about.

Speaking of muddling the discourse, the author regularly trolls on X, providing tons of bad faith arguments and generally trying to rile up a "fil-c vs Rust" war that I think reduces our ability to talk about these differences in a calm, engineering focused context.

Finally, due to its design, fil-c is effectively Linux only. That's great for Linux, but many people also use other systems, and so it is not a meaningful option for them.

Anyway, after saying all that: I still think that it is a good project, and that it should exist and continue to be worked on. I just wish that the heat was turned down, and people could talk about the various approaches and their tradeoffs without turning it into a culture war.

▲

pron 13 minutes ago | parent [-]

> it promotes an "us vs them" mindset, instead of a "we're all trying to improve memory safety" mindset

But you did the same thing when, on the spectrum that ranges from C to ATS, with Zig, Rust, and Java somewhere in the middle (though all closer to C than to ATS), you declared the exact compromise that Rust makes "table stakes"! [1]

Zig improves on C's memory safety when it comes to spatial safety, possibly the more impactful kind, so it, too, could be part of the "we're all trying to improve memory safety", yet you exclude it.

You're trying to draw some hard line that passes exactly between Rust and Zig on the C to ATS spectrum, and I'm trying to say that that line isn't there (your attempt at a definition of delineating safe and unsafe code also applies to C). Obviously, C, Zig, Rust, Java, and ATS all make very different tradeoffs, all of which may be more or less attractive to different people and in different circumstances, but there is no sharp line, at least not one that is meaningful enough to be "table stakes". Your personal inclinations place a premium on the things Rust offers and Zig doesn't while mine are the opposite, but I make no claim to universality.

I'm happy to accept that not everyone shares my aesthetics and can understand why some people prefer Rust, but those claims to or hints at universality annoy me (as they did when they were made by Haskellers, and I actually find Haskell's aesthetics quite pleasing), as they are simply unsupported.

(Now, you may argue that you're only talking about "memory safety" and not correctness in general, but what gives memory safety value is that violations are causes of many dangerous vulnerabilities; but once, say, Java eliminates all of them, 100% of bugs/vulnerability - which are still numerous - will be caused by other problems, all potentially avoidable with ATS, so why isn't ATS table stakes? Of course, the answer is cost, but all the languages on the spectrum differ in their costs.)

[1]: I assume that you meant Rust's compromise, because you implied that Zig doesn't pass that bar but Rust does.

	▲	steveklabnik a minute ago \| parent \| next [-]
		> But you did the same thing when, I do not go around posting "omg Rust is SO MUCH BETTER than zig or fil-c, which are TRASH." I talk about engineering tradeoffs, and what matters to me personally. I do not say "if you use Zig, you are a bad person." I am not saying that any comparison is bad. I am saying that the way that the comparison is presented is bad. That is different. > you declared the exact compromise that Rust makes "table stakes" Table stakes for me. > Zig improves on C's memory safety when it comes to spatial safety, I agree that it's an improvement on C! > yet you excluded it. I said that it is not pursuing a design that I personally find compelling enough to use to write software. That doesn't mean that I think it's worthless. This whole thing started off with me talking about how much I respect the Zig project! Yet you're trying to turn this into something where I'm talking shit. I presented a specific technical tradeoff that is important to me. That is very different. > You're trying to draw some hard line on a spectrum that passes exactly between Rust and Zig, and I'm trying to say that that line isn't there (your attempt at a definition of delineating safe and unsafe code also applies to C) I don't believe you've shown that. And my "attempt" does apply to C: it fails the bar, because it does not delineate between a safe subset and an unsafe superset. > you may argue that you're only talking about "memory safety" and not correctness in general, I am in fact talking about "memory safety" and have been this whole time, yes.
	▲	Maxatar 5 minutes ago \| parent \| prev [-]
		There's a distinction between claiming something is objectively better, which is what Fil-C claims with respect to its "idea" about memory safety compared to Rust... and claiming a personal preference for one approach versus another approach, which is what OP is saying about their own personal preference about how Zig reduces errors compared to how Rust reduces errors. It is absolutely possible that one language might actually have an objectively better approach to memory safety than another, and in such cases it is usually possible to argue for this using sound technical or empirical arguments. But the way the author of Fil-C presents their arguments it often comes across in a kind of antagonistic manner, like he has a chip on his shoulder.