Recent questions tagged rust

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rust - Why is the Copy trait needed for default (struct valued) array initialization?

When I define a struct like this, I can pass it to a function by value without adding anything specific: #[ ... no copy in the first place. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Why can I not return a mutable reference to an outer variable from a closure?

I was playing around with Rust closures when I hit this interesting scenario: fn main() { let mut y = 10; let f = ... if I remove the call f(). See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Is it possible to add your own derivable traits, or are these fixed by the compiler?

The derive attribute allows certain traits to be automatically implemented for data structures. The reference gives the ... by the compiler? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Iterating over a vector of mutable references to trait objects

I have a struct that holds mutable references to trait objects: trait Task { fn do_it(&mut self); } struct Worker<'a ... How do I do it in Rust? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Is it more conventional to pass-by-value or pass-by-reference when the method needs ownership of the value?

When I'm passing a object by reference to a struct's new() method, and the struct will own the object, is ... ::new_by_val(state2.clone()); } See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - How can I include private modules when generating documentation via Cargo?

I'm currently working on a project with Rust and Cargo. It works well, but I encounter a little issue: ... project, for development purpose... See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - How can I distinguish between a deserialized field that is missing and one that is null?

I'd like to use Serde to parse some JSON as part of a HTTP PATCH request. Since PATCH requests don't pass ... such as one using a custom enum. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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958 views

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rust - How do I move values out of an array one at a time?

I have ownership of an array of size 3 and I would like to iterate on it, moving the elements out as I ... ^ cannot move out of borrowed content See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Can I install a library using Cargo without a Cargo.toml?

I am going through Rust's getting started and I need to get the rand crate on my system. I'm not ... -index` specified package has no binaries See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - What's the benefit of using a Result?

I don't understand why Result exists in Rust. I can see how Option can be useful, but using Result just seems to ... how this can be the case. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - Why is using return as the last statement in a function considered bad style?

I was reading through the Rust documentation and came across the following example and statement Using a return as ... the former be encouraged? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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824 views

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rust - How do I create a map from a list in a functional way?

In Scala, there is a method named toMap that works on any list of tuples and converts it to a map where the ... closest thing to toMap in Rust? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rust - How can I convert a hex string to a u8 slice?

I have a string that looks like this "090A0B0C" and I would like to convert it to a slice that looks ... a slice of multiple integer values. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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884 views

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rust - Why does the usage of by_ref().take() differ between the Iterator and Read traits?

Here are two functions: fn foo<I>(iter: &mut I) where I: std::iter::Iterator<Item = u8>, { let x = ... will compile too. Where am I mistaken? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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741 views

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rust - Is there a way to use the cfg(feature) check on multiple statements?

Is there a way to minimize the following feature check? #[cfg(feature = "eugene")] pub mod ... meaning and be more ergonomic. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.1k views

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rust - How to move one field out of a struct that implements Drop trait?

Here's an invalid Rust program (Rust version 1.1) with a function that does an HTTP client request and returns only ... a move, similar to C++? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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726 views

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rust - What are the differences between an impl trait argument and generic function parameter?

impl Traits can be used as function arguments. Are there differences between this and a generic function with a trait ... Foo>(_: T) {} See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.4k views

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rust - How to convert from &[u8] to Vec<u8>?

I'm attempting to simply convert a slice to a vector. The following code: let a = &[0u8]; let b: Vec<u8> = ... of type `&u8` What am I missing? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.1k views

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rust - How to suppress "function is never used" warning for a function used by tests?

I'm writing a program in Rust and I have some tests for it. I wrote a helper function for these tests, but ... so as not to get the warnings? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.1k views

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rust - Creating a vector of zeros for a specific size

I'd like to initialize a vector of zeros with a specific size that is determined at runtime. In C, it would be ... zeros(pattern.len()+1); } See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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619 views

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rust - How to write a custom attribute that injects code into a function

I've gotten as far as having the custom attribute invoked: #[plugin_registrar] pub fn registrar(reg: &mut rustc:: ... How do I achieve that? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.1k views

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rust - How do I get the first character out of a string?

I want to get the first character of a std::str. The method char_at() is currently unstable, as is String:: ... ; let ch = char_vec[0]; See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.0k views

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rust - How to pass rustc flags to cargo?

I am trying to disable dead code warnings. I tried the following cargo build -- -A dead_code ? rla git:( ... I pass rustc arguments to cargo? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.1k views

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rust - How do I use conditional compilation with `cfg` and Cargo?

I want to conditionally compile my source code using cfg with Cargo, after Googling for a while, it seems that the ... -18 01:50:48 +0000) See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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839 views

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rust - What is the easiest way to pad a string with 0 to the left?

What is the easiest way to pad a string with 0 to the left so that "110" = "00000110" "11110000" = "11110000" I ... : format!("{:08}", string); See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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840 views

1 answer

rust - How can I create an is_prime function that is generic over various integer types?

I just took the dive into Rust and want to make some basic math functions that are generic. I have the following ... of traits to my goal here. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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901 views

1 answer

rust - How to get a release build with debugging information when using cargo?

The following command $ cargo build produces a non-optimized build with debugging information. On the ... meaningful profiling information. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.1k views

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rust - How to convert Vec<char> to a string

How to convert Vec<char> to string form so that I can print it? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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