This is a good example for the Borrow trait. use std::borrow::Borrow; struct Bar; trait Foo { fn hi(&self); } impl<B: Borrow<Bar>> Foo for B { fn hi(&self) { print!(“hi”) } } fn main() { let bar = Bar; (&bar).hi(); &bar.hi(); }
In order for a server to provide an external API it needs to be able to deal with Cross Origin Resource Sharing (CORS). CORS is an HTTP-header based mechanism that allows a server to indicate which origins (domain, protocol, or port) that a browser should permit loading of resources. You can create a fairing to … Read more
This feature has been added to Cargo and was stabilized in Cargo 1.56. The accepted answer is now out-of-date. Linker arguments can be specified in build.rs like so: // Pass `-fopenmp` to the linker. println!(“cargo:rustc-link-arg=-fopenmp”);
A macro is expanded during parsing, more or less; it has no access to the AST or anything like that—all it has access to is the stuff that you pass to it, which for my_macro!(S) is purely that there should be a type named S. If you define the struct as part of the macro … Read more
This is the new impl Trait syntax which allows the programmer to avoid naming generic types. The feature is available as of Rust 1.26. Here, it is used in return position to say “the type returned will implement this trait, and that’s all I’m telling you”. In this case, note that all return paths of … Read more
Manual editing You can check out Iron, modify Cargo.toml to specify versions (as you have already done). Then you repeat the process, checking out url, modifying its Cargo.toml, then make sure you are using your version of url in Iron’s Cargo.toml. Rinse and repeat. Patch overrides From the Cargo docs: The [patch] section of Cargo.toml … Read more
You can also implement hex encoding and decoding yourself, in case you want to avoid the dependency on the hex crate: use std::{fmt::Write, num::ParseIntError}; pub fn decode_hex(s: &str) -> Result<Vec<u8>, ParseIntError> { (0..s.len()) .step_by(2) .map(|i| u8::from_str_radix(&s[i..i + 2], 16)) .collect() } pub fn encode_hex(bytes: &[u8]) -> String { let mut s = String::with_capacity(bytes.len() * 2); … Read more
Given that in Rust (unlike C or C++) the address of a value is not considered to matter, there is nothing in terms of language that prevents the elision of the copy. However, today rustc does not optimize anything: all optimizations are delegated to LLVM, and it seems you have hit a limitation of the … Read more
Here you go: use std::io::Read; use std::mem; use std::slice; #[repr(C, packed)] #[derive(Debug, Copy, Clone)] struct Configuration { item1: u8, item2: u16, item3: i32, item4: [char; 8], } const CONFIG_DATA: &[u8] = &[ 0xfd, // u8 0xb4, 0x50, // u16 0x45, 0xcd, 0x3c, 0x15, // i32 0x71, 0x3c, 0x87, 0xff, // char 0xe8, 0x5d, 0x20, 0xe7, … Read more
I want to ignore all Err values Since Result implements IntoIterator, you can convert your Vec into an iterator (which will be an iterator of iterators) and then flatten it: Iterator::flatten: vec.into_iter().flatten().collect() Iterator::flat_map: vec.into_iter().flat_map(|e| e).collect() These methods also work for Option, which also implements IntoIterator. You could also convert the Result into an Option and … Read more