I have this code use std::iter::Step; fn main() { for i in mkiter(25, 20) { println!("{}", i); } for i in mkiter(10, 23) { println!("{}", i); } } fn mkiter<T>(start: T, end: T) -> Box<dyn Iterator<Item = T>> where T: Step, { if start > end { Box::new((end..=start).rev()) } else { Box::new(start..=end) } } However,… Read More How to write a function that returns a RangeInclusive or its reverse iterator in stable Rust?

I’m new to Rust and just bumped into this issue. I have many different structs, that all implement their own new methods, with a varying number of input parameters and types. Every new method does something like this: impl MyStruct { pub fn new(param1: String, param2: u32, param3: char) -> Self { MyStruct { id:… Read More Extracting varying, parameterized 'new' methods to trait

I was working on a bitboard implementation and was trying to implement the index trait but couldn’t return value &bool because this creates a temp value which could not be returned. Is there any way I could return a &bool in another way? use std::ops::Index; pub struct Bitboard(usize); impl Index<usize> for Bitboard { type Output… Read More Return &bool from function

I am trying to create a generic wrapper type to simplify so branching logic however the compiler complains that the Write trait is not implemented for the specific type being used in that function. Not pictured here is the logic of someFunction requires the inner type to do some instructions specific to itself to finish… Read More error: the trait bound `someStruct<std::fs::File>: Write<std::fs::File>` is not satisfied

I have multiple Policy classes. and these policies’ update, delete, restore functions have the same logic evaluation which is to check if the authenticated user owns the resource. For example, I have a Post and a Comment model. Then for PostPolicy and CommentPolicy, both of their update, delete, restore functions will all have: public function… Read More Dynamic model binding in trait function

I am completely new to rust. I created a program to store information about persons to get in touch with the language: person.rs pub struct Person { firstname: String, lastname: String, pub age: u8 } impl Person { pub fn new(firstname: String, lastname: String, age: u8) -> Person { return Person { firstname: firstname, lastname:… Read More Create flexible constructor method accepting either String or &str

I want to turn a &str into a String which can be done simply with the method let res = "my_string".to_string() I prefer thinking of methods as acting directly on a structure so I’d like to write let res = to_string("my_string"). The closest I’ve come to this so far is: str::to_string("my_string") but providing the namespace… Read More How can I import `str::to_string` in Rust? (And is it possible to do this with trait methods in general?)

This function creates a line segment by parsing the string defining the line segment. Since there is an item to parse other than the line segment, I tried to use a trait. I implemented it like below. pub trait GeomParser<T> { fn parse(str_line: &str) -> Result<T, std::num::ParseFloatError>; } impl GeomParser<Segment> for Segment { fn parse(str_line:… Read More Rust trait return type (Result)

I have a struct Lambertian: pub struct Lambertian { albedo: Color, } A Material trait with an associated method: pub trait Material { fn scatter(&self, ray: &Ray, rec: &HitRecord) -> Option<(Ray, Color)>; } And finally, another struct that holds a value of something that implements the Material trait pub struct HitRecord<T> where T: Material {… Read More How to have a trait method have a struct argument, in which an item must implement that same trait?

After struggling for hours with writing a factory method which returns instances of a struct containing a field of a generic type (implementing a trait), I find that it compiles and runs only if I do not assign the result to a variable before returning it (see the bottom of the post for a complete… Read More Method returning dyn fails to compile if the return value is assigned to a variable before returned