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Cake day: July 27th, 2023

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  • This is a use-after-free, which should be impossible in safe Rust due to the borrow checker. The only way for this to happen would be incorrect unsafe code (still possible, but dramatically reduced code surface to worry about) or a compiler bug. To allocate heap space in safe Rust, you have to use types provided by the language like Box, Rc, Vec, etc. To free that space (in Rust terminology, dropping it by using drop() or letting it go out of scope) you must be the owner of it and there may be current borrows (i.e. no references may exist). Once the variable is droped, the variable is dead so accessing it is a compiler error, and the compiler/std handles freeing the memory.

    There’s some extra semantics to some of that but that’s pretty much it. These kind of memory bugs are basically Rust’s raison d’etre - it’s been carefully designed to make most memory bugs impossible without using unsafe. If you’d like more information I’d be happy to provide!



  • I was very intrigued by a follow-up to the recent numberphile video about divergent series. It was a return to the idea that the sum of the integers greater than zero can be assigned the value -1/12. There were some places this could be used, but as far as I know it was viewed as shaky math by a lot of experts.

    As far as I recall the story goes something like this: now, using a new technique Terrence Tao found, a team was seemingly able to “fix” previous infinities in quantum field theory - there’s a certain way to make at least some divergent series work out to being a real number, and the presenter proposed that this can be explained as the universe “protecting us” from the infinities inherent in the math.

    It made me think about other places infinities show up in modern physics (namely, singularities in general relativity) and whether a technique something like this could “solve” them without a whole new framework like string theory is.



  • The issue is that, in the function passed to reduce, you’re adding each object directly to the accumulator rather than to its intended parent. These are the problem lines:

    if (index == array.length - 1) {
    	accumulator[val] = value;
    } else if (!accumulator.hasOwnProperty(val)) {
    	accumulator[val] = {}; // update the accumulator object
    }
    

    There’s no pretty way (that I can think of at least) to do what you want using methods like reduce in vanilla JS, so I’d suggest using a for loop instead - especially if you’re new to programming. Something along these lines (not written to be actual code, just to give you an idea):

    let curr = settings;
    const split = url.split("/");
    for (let i = 0; i < split.length: i++) {
        const val = split[i];
        if (i != split.length-1) {
            //add a check to see if curr[val] exists
            let next = {};
            curr[val] = next;
            curr = next;
        }
        //add else branch
    }
    

    It’s missing some things, but the important part is there - every time we move one level deeper in the URL, we update curr so that we keep our place instead of always adding to the top level.


  • The GPU I used is actually a 1080, with a (rapidly declining in usefulness) Intel 4690k. But I suppose laptop vs desktop can certainly make all the difference. What I really want is GPU virtualization, which I’ve heard AMD supports, but I’m not about to buy a new GPU when what I’ve got works fine.


  • My experience with single GPU passthrough on Proxmox to a media VM was pretty positive, especially for it being an old Nvidia card. Even as someone doing it for the first time, it just took about 10 minutes to figure out the passthrough itself and another ~15 to figure out some driver issues. And it’s worked perfectly since then. All in all much better than what I’d expected.




  • Currying is converting a function with n parameters to n functions that each have one parameter. This is done automatically in most primarily functional languages. Then, partial application is when you supply less than n arguments to a curried function. In short, currying happens at the function definition and partial application happens at the function call.

    Currently the type of test_increment is (int, int) -> unit -> unit. What we want is int -> int -> unit -> unit. The more idiomatic way would have this function definition:

    let test_increment new_value original_value () =
    

    Which would require this change in the callers:

    test_case "blah" `Quick (test_increment 1 0);
    

    See, in most primarily functional languages you don’t put parentheses around function parameters/arguments, nor commas between them - in this case, only around and between members of tuples.


  • I’m not an OCaml person but I do know other functional languages. I looked into Alcotest and it looks like the function after “`Quick” has to be unit -> unit. Because OCaml has currying, and I think test_increment already returns unit, all you should have to do is add an extra parameter of type unit. I believe that would be done like this:

    let test_increment (new_value, original_value) () =
    

    Now the expression test_increment (1, 0) returns a function that must be passed a unit to run its body. That means you can change the lambdas to e.g. this:

    test_case "blah" `Quick (test_increment (1, 0))
    

    I don’t know OCaml precedence rules so the enclosing parentheses here may not be necessary.

    I’d also note that taking new_value and original_value as a tuple would probably be considered not idiomatic unless it makes sense for the structure of the rest of your code, especially because it limits currying like we did with the unit being able to be passed later. Partial application/currying is a big part of the flexibility of functional languages.

    Edit: if you’re getting into functional programming you may also consider calling increment_by_one “succ” or “successor” which is the typical terminology in functional land.




  • sleep_deprived@lemmy.worldtoMemes@lemmy.mlThis community lately
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    1 year ago

    Typically this thinking is mostly correct - e.g. Manifest v3 - but not in this case. If websites see enough users using chormium, via user agent or other fingerprinting, they’ll be more willing to require WEI. And unlike Manifest v3 etc. this affects the whole web, not just users of one browser or the other.

    In every case monopolies are bad. Including in tech.