CODEWITHSUNDEEP
rust
Litty
Litty

Reputation: 1876

Does Rust have syntax sugar for creating an array with an appended element?

I have a 3-element array:

let color = [0.25, 0.25, 0.25];

I'd like to turn it into a 4-element array, which would be the 3-element array plus one appended element:

let color_with_alpha = [color[0], color[1], color[2], 1.0];

I know Rust has some cool syntax sugar for a lot of things; is there something for this? Something like:

let color_with_alpha = [color, 1.0];

I've read about the concat macro but that seems to only create string slices. I would imagine there's a vector-based solution but I don't require the dynamic sizing.

Upvotes: 2

Views: 343

Answers (1)

Shepmaster
Shepmaster

Reputation: 432179

No, there is no such syntax.

It's always hard to prove a negative, but I've implemented a parser of Rust code and I've used Rust for over 3 years; I've never encountered any such syntax.

The closest I can imagine would be to implement a trait for array of various sizes. This is complicated because you cannot move out of non-Copy arrays. Since there's no generic integers, you'd have to implement this trait for every size of array you needed.

trait ArrayAppend<T> {
    type Output;
    fn append(self, val: T) -> Self::Output;
}

impl<T: Copy> ArrayAppend<T> for [T; 3] {
    type Output = [T; 4];

    fn append(self, val: T) -> Self::Output {
        [self[0], self[1], self[2], val]
    }
}

fn main() {
    let color = [0.25, 0.25, 0.25];
    let color2 = color.append(1.0);
}

Upvotes: 3

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