skitter
Joined 6 years ago
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759
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219
Member since
Feb 5
Recent submissions
Comment · 3 months ago
Although not part of the goal, it also mentions `!Destruct`/"must-move types", aka linear types: Instead of there always being a way to drop values without providing any arguments, if you wanna get rid of a value of a linear type you have to call a function that takes it by value.
Comment · 3 months ago
By doing the same as with `Sized`: Automatically including the `Forget` bound on generic parameters and letting methods that don't need to be able to forget them opt out. That way existing code continues to compile and existing unsafe code doesn't become unsound.
Comment · 7 months ago
Why would it be UB? All objects are behind (thin) pointers, which can be overwritten atomically.
Comment · 8 months ago
I don't understand – what's the point of not collecting mass amounts of personal identity documents and face scans and linking them to online identities?
Comment · 11 months ago
I do the same in my toy JVM (to implement the reentrant mutex+condition variable that every Java object has), except I've got a rare deadlock somewhere because, as it turns out, writing complicated low level concurrency primitives is kinda hard :p
Comment · 1 year ago
They're great, compared to cars. But while they have a relatively fast and cheap setup, over the long term light rail and trams are a lot cheaper to run and can coexist with foot & bike traffic easier since the rails make them very predictable.
Comment · 1 year ago
> for the sole purpose of not having to add them to function signatures all over the place.
I thought it was because you couldn't be fully generic over exceptions.
Comment · 1 year ago
The author obviously knows that too, otherwise they wouldn't have written about it. All of these issues are just how the language works, and that's the problem.
Comment · 1 year ago
I do not see evidence that they are against violence against women and girls, only that they are claiming to be.
Comment · 1 year ago
Yup, that's what I'm doing - storing the two bits needed for an object's monitor in the same word as its compressed class pointer. The pointer doesn't change over the lock's lifetime.
Comment · 1 year ago
Fun post! An alternative to using futexes to store thread queues in kernel space is to store them yourself. E.g. the parking_lot[0] Rust crate, inspired by WebKit[1], uses only one byte to store the unlocked/locked/locked_contended state, and under contention uses the address of the byte to index into a global open-addressing hash table of thread queues. You look up the object's entry, lock said entry, add the thread to the queue, unlock it, and go to sleep. Because you know that there is at most one entry per thread, you can keep the load factor very low in order to keep the mutex fast and form the thread queue out of a linked list of thread-locals. Leaking the old hash on resizing helps make resizing safe.
As a result, uncontended locks work the same as described in the blog post above; under contention, performance is similar to a futex too. But now your locks are only one byte in size, regardless of platform – while Windows allows 1-byte futexes, they're always 4 bytes on Linux and iirc Darwin doesn't quite have an equivalent api (but I might be wrong there). You also have more control over parked threads if you want to implement different fairness criteria, reliable timeouts or parking callbacks.
One drawback of this is that you can only easily use this within one process, while at least on Linux futexes can be shared between processes.
I've written a blog post[2] about using futexes to implement monitors (reëntrant mutexes with an associated condvar) in a compact way for my toy Java Virtual Machine, though I've since switched to a parking-lot-like approach.
[0]: https://github.com/amanieu/parking_lot [1]: https://webkit.org/blog/6161/locking-in-webkit [2]: https://specificprotagonist.net/jvm-futex.html
Comment · 1 year ago
If you're interested in how the mountains and rivers are generated, it's mostly based on the paper "Large Scale Terrain Generation from Tectonic Uplift and
Fluvial Erosion": Each chunk rises (at a noise-based, constant rate) while erosion is applied based on the chunk's slope and the size of its catchment area.
The result is a river network as well as the central height of each chunk; based on this roads, caves and structures are laid out. The actual voxels are only determined when a player loads the area and are (usually) not persisted.
Also, for some technologies not related to worldgen: Rendering is done via wgpu, models are built in MagicaVoxel, and both client and server use an ECS (specs).
Comment · 1 year ago
They're rather different: In Rust types only exist at compile time; dyn Any is a normal trait object, so you can only call the trait's methods. With C#'s dynamic, you can call arbitrary methods and access any fields with type checking of those accesses being delayed until runtime, which works because types exist at runtime too.
Rust's dyn Any corresponds better to C#'s Object; dynamic exists to interface with dynamic languages and is rarely used.
Comment · 1 year ago
Why limit yourself to one language, when you can have 23 of them in the same Datei?
Comment · 1 year ago
…what? Why bring "AI" into this?