Function from_fn

pub fn from_fn<F, T>(f: F, len: Option<usize>) -> FromFn<F>
where
    F: Fn(usize) -> Option<T>,

A slice made by calling a closure on the index.

Analagous to core::iter::from_fn.

Examples

let slice = slice_utils::from_fn(|i| Some(i * i), Some(5));
assert_eq!(slice, [0, 1, 4, 9, 16]);