43,716 questions
0
votes
1
answer
9
views
Type gymnastics of heterogeneously-typed lists in Rust
I'm designing a pass system inspired by frunk.
Background
This is a little introduction of the Selector in frunk. If you are familiar with it, just skip this section.
Roughly speaking, frunk uses a ...
- 1,225
0
votes
0
answers
14
views
Rapier does not move RigidBody in expected direction
I have a RigidBody with the components (Velocity, Transform). When changing the rotation with transform.rotation = …, the “forward” direction of the body remains the same when adding velocity. How ...
0
votes
0
answers
58
views
Is vector reallocation bad? (Arena tree implementation) [closed]
Let's say I have a tree, implemented with a Vec-backed arena and type NodeID = Option<u32> as references to locations in the arena. This tree can grow to an arbitrary large size.
The naive ...
- 2,564
1
vote
1
answer
45
views
How to downcast any List or any Option in rust
I want to add properties window with auto properties based on struct fields. I'am downcasting every field, but for Vec<> and Option<> I have to duplicate all code, how can I automatically ...
1
vote
2
answers
112
views
Extract value from nested Box<T>
In my project I have recursive enum that holds various constraints. One of the variants implies that constraint is negated.
#[derive(PartialEq, Eq, PartialOrd, Ord, Debug)]
enum A {
NOT(Box<A&...
- 1,311
0
votes
1
answer
77
views
serini failing to deserialize windows path with "r" "n" or "t" as first letter of directory
I have a structure that I need to write to disk, it keeps track of a number of resources including a folder where stuff is saved. I'm finding that when I deserialize the folder if the path contains ...
-3
votes
0
answers
28
views
The command "cargo build-sbf" is not working for me?
Whenever I run cargo build-sbf I get the following error:
error: no such command: `+solana`
help: invoke `cargo` through `rustup` to handle `+toolchain` directives
When I reinstall solana-cli to ...
0
votes
0
answers
50
views
How can I fix this so my function can be used as an Axum handler? [duplicate]
I'm using Axum 0.8.4 and trying to register a route with a handler that takes both Query and Extension extractors. But I get this trait bound error saying the function doesn't implement Handler<_, ...
- 148
0
votes
1
answer
78
views
Multithreaded Web Server from the Rust book, but implemented with shared memory instead of message passing
I'm following the Rust Book's chapter 20 to create a multithreaded web server. Everything went pretty smooth, the implementation they describe up until the end of this chapter works as expected.
Here'...
- 228
0
votes
0
answers
100
views
How do I avoid memory being swapped in Rust?
TLDR: I have a huge array (around 70% of available memory) and I don't want it to be swapped to disk. What's the best way on modern linux to pin a vector in memory so that it doesn't get swapped by ...
- 2,564
2
votes
0
answers
104
views
+50
Custom hasher is faster for insert and remove, but when done together is slower, when comparing to std::collections::HashMap
I wish to benchmark various hashmaps for the <K,V> pair <u8, BoxedFnMut> where BoxedFnMut.
type BoxedFnMut = Box<dyn FnMut() + Send + 'static>;
To do this, I am using divan(0.1.21) ...
- 492
2
votes
1
answer
91
views
Why can the argument of a function implicitly change its type from &&T to &T? [duplicate]
Consider the following example, the test function receives the &str type, but it works when I transfer it &&str, &&&str, &&&&str. What's the rule? I don't think ...
- 423
4
votes
1
answer
58
views
Wrapped stream Unpin behaves unintuitively
After half a year of Rust coding, today I am for the first time truly baffled by a compiler error. Here is the condensed version of a library concept I was working on:
use futures::{Stream, StreamExt, ...
- 95.7k
4
votes
1
answer
46
views
Constrained type is unconstrained?
I've been writing Rust for a several months now, and I've come across this headscratcher:
I have the following code:
trait MyTrait {}
impl MyTrait for String {}
impl MyTrait for str {}
impl MyTrait ...
- 1,875
2
votes
0
answers
49
views
How can I create queries in diesel where the order criterion is supplied by a method?
I am building a backend in Rust and use diesel to access a Postgres database. I want to be able to supply the ordering with its own function.
This function should take an Option<String> as ...
- 116