Rust code shared from the playground

playground.rs

#[derive(Debug, Copy, Clone)]
enum DotError {
    LengthMismatch
}

trait Dot<Rhs=Self> {
    type Output;
    fn dot(&self, other: &Rhs) -> Self::Output;
}

impl Dot for [i32; 3] {
    type Output = i32;
    fn dot(&self, other: &[i32; 3]) -> Self::Output {
        self.iter().zip(other.iter()).fold(0, |acc, (&a, &b)| {
            acc + a * b
        })
    }
}

impl Dot for Vec<i32> {
    type Output = Result<i32, DotError>;
    fn dot(&self, other: &Vec<i32>) -> Self::Output {
        if self.len() == other.len() {
            let product = self.iter().zip(other.iter()).fold(0, |acc, (&a, &b)| {
                acc + a * b
            });
            
            Ok(product)
        } else {
            Err(DotError::LengthMismatch)
        }
    }
}

fn main() {
    let a = [1, 2, 3];
    let b = [1, 2, 3];
    let _c = [1, 2, 3, 4];
    
    println!("{:?}", a.dot(&b));
    // println!("{:?}", a.dot(&_c)); // compile time error
    
    let c = vec![1, 2, 3];
    let mut d = vec![1, 2, 3];
    
    println!("{:?}", c.dot(&d));
    d.push(4);
    println!("{:?}", c.dot(&d)); // runtime error
    
    
}