The issue I see is that Greg did spoke in a way that would not undermind Linux leadership. If Linux was out, I’m sure Greg would have said stuff publicly much earlier.

Indeed, it’s very good. I wish he had send this before 2 Rust maintainers resigned, but I assume that he did not want to undercut Linus decisions.

First experience with #jj #jujitsu

I tried the equivalent of git add -p (jj squash -i).

• I realize that it’s closer to git add --interactive (which I find much more complicated and less productive)
• I wasn’t able to edit a hunk (like the e key in git add -p) which I use a lot to split debug statements from real work

I generated a conflict (as I expected)

• I found no way to show the original diff
• jj undo did not worked (I have not been able to undo the jj squash that introduced the conflict

Very not impressed so far. Fortunately it was a test repo.

It’s really nice to see this RFC progress

I never realised it was that simple to do. Thanks a lot to answer the OP question. I had the same for longer than I wish to admit given how easy the answer was!

I think you have a hard time understanding the différence between “not possible” and “much harder”.

In Rust, the code does not compile.

In C++ the code compile, but

• if you have a test case
• this test case triggers the bug (it is not guarateed to properly reproduce you production environment since it depends on the parameters of the allocator of your vector)
• you use ubsan

… then the bug will be caught.

Yes it is possible, noone says the opposite. But you can’t deny it’s harder. And because its harder, more bugs get past review, most notably security bugs as demonstrated again and again in many studies. The

That’s why I did not said it was impossible, just order of magnitude harder to catch in C++ compared to Rust.

To have asan finding the bug, you need to have a valid unit test, that has a similar enough workload. Otherwise you may not see the bug with asan if the vector doesn’t grow (and thus ref would still be valid, not triggering UB), leading to a production-only bug.

Asan is a wonderfull tool, but you can’t deny it’s much harder to use and much less reliable than just running your compiler.

void foo() {
    std::vector v = {0, 1, 2, 4};
    const auto& ref = v[1];
    add_missing_values(v);
    std::cout << ref << "\n";
}

void add_missing_values(std::vector<int>& v) {
    // ...
    v.push_back(3);
}

Neither foo(), nor add_missing_values() looks suspicious. Nonetheless, if v.push_back(3) requires v to grow, then ref becomes an invalid reference and std::cout << ref becomes UB (use after free). In Rust this would not compiles.

It is order of magnitudes easier to have lifetime errors in C++ than in Rust (use after free, double free, data races, use before initialisation, …)

Is it possible to do in Rust?

Yes

Is possible to do in Rust, by mistake, and not easily caught by a review?

Definitively not.

The quote (and the associated discussion) is such an important part of Rust and why I love this language so much. Anything that can be automated should at one point be automated reliably, and the sooner the better.

I absolutely agree that method extraction can be abused. One should not forget that locality is important. Functionnal idioms do help to minimise the layer of intermediate functions. Lamda/closure helps too by having the function much closer to its use site. And local variables can sometime be a better choice than having a function that return just an expression.

Good advice, clear, simple and to the point.

Stated otherwise: “whenever you need to add comments to an expression, try to use named intermediate variables, method or free function”.

I never understood why python won agaist ruby. I find ruby an even better executable pseudo code language than python.

The issue is that the notion of “tomorrow” becomes quite hard to express. If it’s 20:00 when the sun rose, when does tomorrow starts? In 5 hours ?

Interesting idea indeed. I’ve never used async yet, but I’m always surprised at how the problem space seems to be much more complicated than what it initially looks like.

I would have liked a link to the LKLM thread. Usually they are quite informative

I use a 42 key layout modified from bépo (french dvorak inspired layout) with the altgr layer of ergol. Go check this altgr layer it’s awesome for programming, and there is a version compatible for qwerty and lafayette.

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It’s also what I understood from what I read but I assume it was just a poor choice of word. Debug symbols are way too important for debugging to be stripped by default.

Usually when people say “I suck at maths”, it means that they are bad at doing manual calculus. Maths is extremely useful in programming, but it’s absolutely not the same kind of math. I don’t think that the grade you had in math at school will influence in any if you will be good or bad in programming.

There take on what they call capabitilites is very interesting. Basically anything that would make a function non-pure seems to be declared explicitely.

A computational effect or an “effectful” computation is one which relies on or changes elements that are outside of its immediate environment. Some examples of effectful actions that a function might take are:

• writing to a database
• throwing an exception
• making a network call
• getting a random number
• altering a global variable