One thing that impressed me about Zig is how simple the language is. I get the impression that it would take very little time to properly learn the language and become effective at it.
Rust, on the other hand, has a whole lot of complexity even without the ownership semantics. So much to learn and understand. And, in some cases, work around. It seems, from looking at others' code, that there is a very strong temptation to lean on `unsafe` instead of figuring out how to solve a problem within the constraints it normally applies.
That has me wondering if there's really all that much safety difference in practice? Simpler code is generally easier to understand, and it's generally easier to find and fix bugs in code that's easier to understand. I can imagine a world where it's a tradeoff between, "You definitely won't have any of this relatively narrow category of bug, unless of course you opt out of the static checks, which you will probably do sometimes, even though we tell you you shouldn't," and, "There are no particular guarantees, but you're generally less likely to have any of this broader category of bug."
Some people do believe that, let's say "conceptually parsimonious" languages (using complicated words to describe simplicity is amusing to me, sorry) do exactly what you say. Others believe that complexity inherently exists, and you can put it in the language, where a compiler can tirelessly check certain properties for you or a runtime can do magical complicated work on your behalf, or you can put it in the programs, where users have to check such things themselves.
Another way I heard this expressed one time is Ruby vs Python. I once heard someone talk about how they preferred Python as a language more, because it was simpler, but enjoyed actually programming in Ruby more, even thought it was more complex, and they value simplicity. The reason is that all of that nasty ugly stuff Ruby lets you do makes you be able to make extremely nice APIs. Things you couldn't do, or just folks don't do, in Python. And therefore they ended up liking using Ruby more in practice.
I suspect that this is a topic that we, as a profession, will debate about endlessly.
I think we'd all agree there's a spectrum, with, say, Assembly on one end and Idris on the other, where neither Zig nor Rust are near either extreme, and are actually rather close to each other. It's not a matter of accepting or rejecting a principle, but on picking slightly different sweet spots (hopefully) on a tradeoff spectrum.
Rust doesn't check at compile-time most things that could be checked at compile-time. In fact both language check almost the same things at compile-time, and almost the same things at runtime. The design differences come down to one or two things that are clearly tricky and that neither language "does for you" -- i.e. you still need to think about them -- but are, indeed, checked in different ways.
I personally would not agree with
> Languages with more powerful abstraction abilities bring joy to the writer but make things tedious for the reader.
I find map/filter to be easier to read than a C-style for loop. Things that are conceptually denser make discussion between experts easier, even if it makes things harder for non-experts. This is why jargon exists, for example.
In short I believe languages that one can pick up in a couple of days and then read code where reasoning of the code is highly local would stand a higher chance of being perceived as simple.
Programmers notoriously conflate "simple" and "easy" (classic talk: https://www.infoq.com/presentations/Simple-Made-Easy/) and so I believe languages that are easy for a lot of programmers will also be perceived as simple, whether or not that's accurate.
char* c_foo(char* bar) { ... }
fn rust_foo<'a>(bar: &'a str) -> &'a str { ... }
On the one hand, c_foo is shorter and doesn't use strange symbols. On the other hand, rust_foo doesn't leave you guessing on whether the returned value needs to be free()d or not, and whether the heap allocation backing `bar` can be free()d after the call or not.
fn rust_foo(a: &str) -> &str { ... }
Are you sure those examples of unsafe Rust code were written using unsafe in order to work around safety constraints due to difficulty?
I ask because there are some very real and valid use cases for unsafe code in Rust that have nothing to do with the fact that writing the code safely might be more difficult.
The big bias I'm working from here is that, as an outsider, I have a hard time reconciling all the big talk about how Rust makes it impossible to experience certain classes of bugs, with the existence of a known set of things that its type checker can't check, and which includes a lot of things that are difficult to avoid. One could be forgiven for thinking that the Rust community has a habit of keeping its fingers crossed behind its back when talking.
I don't want to make the perfect the enemy of the good, of course. I realize the feature is there for an important reason. But it sure looks to me like Zig is also good despite being imperfect. Perhaps they're both similarly good languages.
https://doc.rust-lang.org/book/ch19-01-unsafe-rust.html
The spec here is to turn one mutable slice into two non-overlapping mutable slices. The operation does not violate memory safety; we wind up with only one mutable reference to any part of the object. But the compiler does not know how to verify that the programmer has done this correctly. Here, 'unsafe' means 'I certify that this is safe, use that as a lemma to do further checking'.
It is a big difference to have it on your face that something might need to be properly double checked and having each line of code as possible security exploit.
Would you consider Oberon to belong in the former or latter category? On one hand, there's no explicit code blocks as such (syntactically). On the other hand, unsafe primitive operations are limited to the SYSTEM module, so functions calling operations in the SYSTEM module can be considered doing unsafe things.
Just like Modula-2 already does it.
And just like languages with unsafe code blocks, there are compilers that have switches to forbid the use of tainted modules unless explicitly allowed.
In any case, way better than what C, C++ and Objective-C offer, regarding security per line of code.
It's far worse than that, the problem is that the machine can't know what was intended. The result 5 from calling sum([1,2,1,1]) makes sense, but alas this function was intended to produce the product not the sum, the inputs were supposed to be [1,2,3,4] and the desired result was 24... the machine can't hope to guess that.
A program may be buggy even if it its meaning is transparent and exactly reflects its effect, simply because it doesn't reflect the intention of the person who wrote the wrong program.
This quote is attributed to Babbage:
'On two occasions I have been asked, – "Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?" ... I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question'
But that is what we wanted, even if we obviously can't have it.
I don't think that's the parallel I would draw.
Rather, I think both Zig and Rust aim to serve the use cases C and C++ do, but Zig and Rust pick different points on the tradeoffs involving safety. Zig feels like a "better C", in the sense of bringing modern language features to C, but it chooses safer rather than safe. Rust supplies modern language features as well, and chooses to prioritize safe; sometimes that comes at the expense of other factors, such as productivity or compile time. I personally prefer the point on the spectrum that Rust chose, but I think Zig still offers improvements over C.