rust

问题 I am really new to Rust, I am having trouble solving this error, but it only happens if I comment out the while statement , basicly I am asking values from the console and storing it in a HashMap: use std::collections::HashMap; use std::io; fn main() { let mut customers = HashMap::new(); let mut next_customer = true; while next_customer { let mut input_string = String::new(); let mut temp_vec = Vec::with_capacity(3); let mut vec = Vec::with_capacity(2); println!("Insert new customer f.e =

问题 I have the following working code that isn't very DRY: impl<'a, G, E, N, EW, NW, ER, NOW, EOW> Overlay<'a, G, E, N, EW, NW, ER, NOW, EOW> where &'a G: GraphBase<EdgeId = E, NodeId = N> + Data<EdgeWeight = EW, NodeWeight = NW> + DataMap, ER: EdgeRef<Weight = EW, EdgeId = E, NodeId = N>, E: Copy + Eq + Hash, N: Copy + Eq + Hash, { fn overlayed_elements(&'a self) -> OverlayedItems<'a, G, E, N, EW, NW, ER, NOW, EOW>{ OverlayedItems{ overlay: self, phase: Phase::Nodes(self.nodes.iter()), node

问题 Is it possible to print a backtrace (assuming RUST_BACKTRACE is enabled) without panicking? It seems that the only way of doing that is calling via panic! . If not, is there a reason for it? 回答1: Rust uses the backtrace crate to print the backtrace in case of panics (has been merged in PR #60852). A simple example can be found in the crate documentation use backtrace::Backtrace; fn main() { let bt = Backtrace::new(); // do_some_work(); println!("{:?}", bt); } which gives for example stack

问题 I have an input vector which contains numbers. In an output vector, I need to get a sequence of partial products but in right-to-left order. The last element of the output must be equal to the last one in the input; the second-to-last element of the output must be a product of the last and second-to-last elements of input; and so on. For example, if the input vector is let input = vec![2, 3, 4]; then I need the output to be [24, 12, 4] . My implementation takes an iterator over the input,

问题 In Learning Rust With Entirely Too Many Linked Lists, they show that a pub enum can't hold a private struct :, struct Node { elem: i32, next: List, } pub enum List { Empty, More(Box<Node>), } This will cause the compiler to complain: error[E0446]: private type `Node` in public interface --> src/main.rs:8:10 | 8 | More(Box<Node>), | ^^^^^^^^^^ can't leak private type But this code will not cause an error even though Link is private: pub struct List { head: Link, } enum Link { Empty, More(Box

问题 Similar questions have been asked many times before, but the closest I have come to my case is here. I'm trying to achieve something like this(although the match part is completely wrong). struct A { a: i8, b: u8, } struct B { c: i16, d: u16, } enum select { type_a(A), type_b(B), } impl select { fn return_one<T>(&self) -> T { match self { type_a(a) => a, type_b(b) => b, } } } As you can see, it has an extra caveat, where the values inside the enum can be either of two structs. Is there some

问题 This question already has answers here : How do I create a global, mutable singleton? (2 answers) How can you make a safe static singleton in Rust? (2 answers) Closed 4 days ago . I'm trying to port a Go language chess engine ( https://github.com/easychessanimations/gobbit ) to Rust ( https://github.com/easychessanimations/rustengine ). Problem with Go is that it produces a WASM executable which is bloated in size because it contains the whole Go runtime ( > 2 MB ). Also the native executable

问题 This question already has answers here : How do I create a global, mutable singleton? (2 answers) How can you make a safe static singleton in Rust? (2 answers) Closed 4 days ago . I'm trying to port a Go language chess engine ( https://github.com/easychessanimations/gobbit ) to Rust ( https://github.com/easychessanimations/rustengine ). Problem with Go is that it produces a WASM executable which is bloated in size because it contains the whole Go runtime ( > 2 MB ). Also the native executable

问题 Looking at the function signature of js_sys::Uint8Array::new_with_byte_offset_and_length pub fn new_with_byte_offset_and_length( buffer: &JsValue, byte_offset: u32, length: u32 ) -> Uint8Array It needs an argument buffer which refers to the current wasm instance's memory buffer. How do I access such an object from the Rust side ? (that gets compiled to wasm) 回答1: It needs an argument buffer which refers to the current wasm instance's memory buffer. First of all, it's worth noting that this is

问题 I'm creating a simple matrix struct in Rust and I'm trying to implement some basic operator methods: use std::ops::Mul; struct Matrix { cols: i32, rows: i32, data: Vec<f32>, } impl Matrix { fn new(cols: i32, rows: i32, data: Vec<f32>) -> Matrix { Matrix { cols: cols, rows: rows, data: data, } } } impl Mul<f32> for Matrix { type Output = Matrix; fn mul(&self, m: f32) -> Matrix { let mut new_data = Vec::with_capacity(self.cols * self.rows); for i in 0..self.cols * self.rows { new_data[i] = self