Recent questions tagged Rust

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rust - What is the difference between <T: Trait> Box<T> and &Trait / Box<Trait>?

When writing code with traits you can put the trait in a trait bound: use std::fmt::Debug; fn ... one of several intermingled concepts) See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Is it possible to have a constructor function in a trait?

I'm trying to find examples for constructor functions in traits, but haven't had much luck. Is this a ... terminated with error code 101 See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Is there a built-in way to compare two iterators?

I've written the following function to compare two iterators, element-by-element. However, it would be great if I could ... !(iter_eq(a, b)); } See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Does this error message mean I can use pattern matching in for loops?

I do not expect the following code to work, but as part of grammar exploration, I tried in playground: fn main( ... the right grammar to do so? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - How can you easily borrow a Vec<Vec<T>> as a &[&[T]]?

How can you easily borrow a vector of vectors as a slice of slices? fn use_slice_of_slices<T>(slice_of_slices: &[&[T]]) ... ]]> for Vec<Vec<T>>? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Decimal number to hexadecimal string

Does Rust have a set of functions that make converting a decimal integer to a hexadecimal string easy? I ... I overthinking this whole thing? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Manipulating an object from inside a loop that borrows it

I'm writing some code in Rust that connects to a remote server, and depending on the messages sent by that ... actual solution would look like). See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - mutably borrow fields from a mutably borrowed struct

from the borrowing rule: At any given time, you can have either one mutable reference or any number of immutable ... any doc to support it. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Lifetime issue when using the Any trait to get references to structs containing references

I ran into a lifetime problem with a little game. The below code represents a very boiled down version of the ... , or why is this impossible? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Do I have to use a usize to access elements of a vector?

I have a 2D vector that rejects indexing using i32 values, but works if I cast those values using as usize: #[ ... i32 to index shouldn't work. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Cannot move out of captured variables in an `FnMut` closure

pub fn create_future( notificator: mpsc::Sender<usize>, proxy: Proxy, ) -> impl Future<Item = (), Error = () ... ? How can I solve this problem? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Iterating through a recursive structure using mutable references and returning the last valid reference

I'm trying to recurse down a structure of nodes, modifying them, and then returning the last Node that I get to. ... = temp, } } current } See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Opposite of Borrow trait for Copy types?

I've seen the Borrow trait used to define functions that accept both an owned type or a reference, e.g. T or ... of writing this sort of thing? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Mutable borrow in function argument

Why doesn't the following code compile (playground): use std::collections::HashMap; fn main() { let mut h: ... still not finished in all cases? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Why do the coherence rules raise the error "the type parameter must be used as the type parameter for some local type"?

Why does code example 1 compile but example 2 gives a compilation error? Example 1: use std::ops::Index; ... be implemented for a type parameter See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Explicit lifetime declarations in trait objects held by structs

In the answer to this question there's a discussion of how to refer to trait objects held by structs which ... is a lifetime bound already. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Can you create a function that takes another function and a parameter and returns a lazy stream of nested function calls?

In Clojure, I use a function called iterate that: Returns a lazy sequence of x, (f x), (f (f x)) etc. f must be free ... => Some(3 * n + 1) } } See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - How to generate documentation for private items

I have a project with: main.rs module_1/mod.rs module_2/mod.rs module_2/module_3/mod.rs when I run cargo doc ... that. Somebody can explain me? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - "cannot infer an appropriate lifetime for pattern due to conflicting requirements" in `ref mut` pattern

struct RefWrap<'a> { wrap: &'a mut Option<String>, } impl<'a> RefWrap<'a> { fn unwrap(&mut self) -> &' ... sure it's not helpful in this case. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - How do I decide when to mark a function as unsafe?

When is it appropriate to mark a function as unsafe versus just using an unsafe block? I saw this function while ... to use one or the other. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Parameter type may not live long enough (with threads)

This is similar to Parameter type may not live long enough?, but my interpretation of the solution doesn't seem to ... am I doing wrong here? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Calling a method on a value inside a mutable Option

I have a mutable Option type and I'm trying to mutate the thing inside the Some but I can't figure out ... an example to help me understand? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Why is the value moved into the closure here rather than borrowed?

The Error Handling chapter of the Rust Book contains an example on how to use the combinators of Option and ... done without the explicit move? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Where does rustup install itself to?

I understand that rustup installs the rustc and cargo binaries to ~/.cargo/bin, but where does it install the ... if that makes a difference. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Access submodule from another submodule when both submodules are in the same main module

I'm using rustc 1.0.0 (a59de37e9 2015-05-13) (built 2015-05-14) and I've got the following setup: my_app/ | ... `???` What am I missing? Thanks. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - How can I specify linker flags/arguments in a build script?

I'm using Rust, bindgen, and a build script to work on some FFI bindings to a library. This library is ... specifying it from within build.rs? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - How to use the same iterator twice, once for counting and once for iteration?

It seems that an iterator is consumed when counting. How can I use the same iterator for counting and then iterate on it? ... ("{}", value); } } See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Is there a non-messy way to chain the results of functions that return Option values?

I have some code that looks like this: f(a).and_then(|b| { g(b).and_then(|c| { h(c).map(|d| ... , d) } rescue NonexistentValueException { None } See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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