In short: the * triggers an explicit deref, which can be overloaded via ops::Deref. More Detail Look at this code: let s = “hi”.to_string(); // : String let a = &s; What’s the type of a? It’s simply &String! This shouldn’t be very surprising, since we take the reference of a String. Ok, but what … Read more
I don’t believe there’s a direct function equivalent to liftM2, but you can combine Option::and_then and Option::map like this: fn main() { let a = Some(5); let b = Some(10); let f = |a, b| { a + b }; println!(“{:?}”, a.and_then(|a| b.map(|b| f(a, b)))); } Output: Some(15)
Install the extension rust-analyzer (the officially recommended vscode extension), and add the following to settings.json: “[rust]”: { “editor.defaultFormatter”: “rust-lang.rust-analyzer”, “editor.formatOnSave”: true }
This issue is not reproducible with recent release of CodeLLDB. CodeLLDB v1.7.0 rust : 1.60.0 (7737e0b5c 2022-04-04) vscode: v1.67.0 Everything works as expected the debug view shows iter: {end:0x000055555559105f} c: ‘t’ Upgrading the codelldb to specified version will resolve the issue.
As a fan of lambda calculus I decided to attempt this and it is indeed possible, though a bit less sightly than in Haskell (playground link): use std::rc::Rc; use Term::*; #[derive(Clone)] enum Term { Hol(Box<Term>), Var(usize), Lam(Rc<dyn Fn(Term) -> Term>), App(Box<Term>, Box<Term>), } impl Term { fn app(t1: Term, t2: Term) -> Self { App(Box::new(t1), … Read more
Not yet, officially, though it should be at least possible with not too much hacking. The biggest obstacle is that the libraries do not have any ability to do dynamic loading yet. Here’s a potential strategy to make it work (on Rust’s incoming branch). Link to the rustc crate to drive the compiler programmatically. Be … 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
Trait objects The most extensible way to implement a heterogeneous collection (in this case a vector) of objects is exactly what you have: Vec<Box<dyn ThingTrait + ‘static>> Although there are times where you might want a lifetime that’s not ‘static, so you’d need something like: Vec<Box<dyn ThingTrait + ‘a>> You could also have a collection … Read more
Here’s a literal answer, but don’t actually use this! #![feature(test)] extern crate test; #[path = “../src/foo.rs”] // Here mod foo; #[bench] fn bencher(_: &mut test::Bencher) { println!(“{:?}”, foo::Thang); } In fact, it’s very likely that this won’t work because your code in foo.rs needs supporting code from other files that won’t be included. Instead of … Read more
Yes. The Rust team has published a new version of Rust 1.59.0 in Feb. 24, 2022, you can now use tuple, slice, and struct patterns as the left-hand side of an assignment. Announcing Rust 1.59.0 Destructuring assignments You can now use tuple, slice, and struct patterns as the left-hand side of an assignment. let (a, … Read more