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(); }
Scala has experimental support for SAMs starting with 2.11, under the flag -Xexperimental: Welcome to Scala version 2.11.0-RC3 (OpenJDK 64-Bit Server VM, Java 1.7.0_51). Type in expressions to have them evaluated. Type :help for more information. scala> :set -Xexperimental scala> val r: Runnable = () => println(“hello world”) r: Runnable = $anonfun$1@7861ff33 scala> new Thread(r).run … Read more
Short answer: you don’t need the mod phone in phone.rs. Just remove that and your code will work (assuming the rest of the code is correct). Longer answer: The following code in main.rs: pub mod phone; is equivalent to: pub mod phone { // literally insert the contents of phone.rs here } so you don’t … Read more
As of Rust 1.24.1, the array length basically needs to either be a numeric literal or a “regular” constant that is a usize. There’s a small amount of constant evaluation that exists today, but it’s more-or-less limited to basic math. a perfectly valid expression in other contexts, just not as a length parameter to an … Read more
I think for now the only way to do what you want is: class MyHelloWorld extends Base { use SayWorld { SayWorld::__construct as private __swConstruct; } public function __construct($a, $b, $c = 0) { $this->__swConstruct($a, $b, $c); } } Edit 2: My advice, based on over a year of dealing with traits in PHP, is: … Read more
Public Service Announcement: I want to state for the record that I believe traits are almost always a code smell and should be avoided in favor of composition. It’s my opinion that single inheritance is frequently abused to the point of being an anti-pattern and multiple inheritance only compounds this problem. You’ll be much better … Read more
what does it mean “generic type parameters that are filled in with concrete type parameters when the trait is used” An example that won’t work is when the type parameter is part of a method: trait Foo { fn foo<T>(t: T) {} } When a function has a type parameter, Rust will monomorphize the function … Read more
In order to avoid the move, use the Read::by_ref() method. That way, you only borrow the BufReader: for (index, line) in buffer.by_ref().lines().enumerate() { … } // ^^^^^^^^^ // you can still use `buffer` here
In Rust, you can use extension traits, that is a trait with a generic implementation for all types T that implement the base trait: struct Kaz {} impl Foo for Kaz {} trait Foo { fn sample1(&self) -> isize { 111 } } trait FooExt { fn sample2(&self); } impl<T: Foo> FooExt for T { … Read more
As this error states, you cannot implement a trait for a type you don’t own: the impl does not reference any types defined in this crate; only traits defined in the current crate can be implemented for arbitrary types However, you can implement Display for your wrapper type. The piece you are missing is to … Read more