Function array_init

src/lib.rs:70–84

Initialize an array given an initializer expression. The initializer is given the index of the element. It is allowed to mutate external state; we will always initialize the elements in order. # Examples ```rust # #![allow(unused)] # extern crate array_init; # // Initialize an array of length 50 containing // successive squares let arr: [usize; 50] = array_init::array_init(|i| i * i); assert!(

(mut initializer: F)

/// assert!(arr.iter().enumerate().all(|(i, &x)| x == i * i));
/// ```
pub fn array_init<F, T, const N: usize>(mut initializer: F) -> [T; N]
where
    F: FnMut(usize) -> T,
{
    enum Unreachable {}

    try_array_init(
        // monomorphise into an infallible version
        move |i| -> Result<T, Unreachable> { Ok(initializer(i)) },
    )
    .unwrap_or_else(
        // zero-cost unwrap
        |unreachable| match unreachable { /* ! */ },
    )
}

#[inline]
/// Initialize an array given an iterator