Function array_init::try_array_init

pub fn try_array_init<Err, F, T, const N: usize>(
    initializer: F
) -> Result<[T; N], Err>where
    F: FnMut(usize) -> Result<T, Err>,

Initialize an array given an initializer expression that may fail.

The initializer is given the index (between 0 and N - 1 included) of the element, and returns a Result<T, Err>,. It is allowed to mutate external state; we will always initialize from lower to higher indices.

Examples

#[derive(PartialEq,Eq,Debug)]
struct DivideByZero;

fn inv(i : usize) -> Result<f64,DivideByZero> {
    if i == 0 {
        Err(DivideByZero)
    } else {
        Ok(1./(i as f64))
    }
}

// If the initializer does not fail, we get an initialized array
let arr: [f64; 3] = array_init::try_array_init(|i| inv(3-i)).unwrap();
assert_eq!(arr,[1./3., 1./2., 1./1.]);

// The initializer fails
let res : Result<[f64;4], DivideByZero> = array_init::try_array_init(|i| inv(3-i));
assert_eq!(res,Err(DivideByZero));