Derive Ord for GamepadButtonType.

[shanecelis]

Objective

Use GamepadButtonType with library that requires Ord.

Motivation

KeyCode derives Ord that I'm using with a trie for recognizing input sequences. I would like to do the same for GamepadButtonType but am stymied by it not deriving Ord.

Solution

This PR add derivations PartialOrd and Ord for GamepadButtonType.

Workaround

If deriving Ord is not possible, I'd be happy to know how I might coerce GamepadButtonType into a u32 or something else that is Ord, so I can wrap GamepadButtonType in a newtype. I suppose serializing with serde may work or reflect?

[Kanabenki]

I don't see any reason not to implement those traits here, looks good to me 🙂

[shanecelis]

Reflect Workaround

I did find this cursed workaround.

#[derive(PartialEq, Eq, Clone, Debug)]
pub(crate) struct GamepadButton(GamepadButtonType);

impl From<GamepadButtonType> for GamepadButton {
    fn from(a: GamepadButtonType) -> Self {
        Self(a)
    }
}

impl PartialOrd for GamepadButton {
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
        use bevy::reflect::Enum;
        self.0.variant_index().partial_cmp(&other.0.variant_index())
    }
}

impl Ord for GamepadButton {
    fn cmp(&self, other: &Self) -> Ordering {
        use bevy::reflect::Enum;
        self.0.variant_index().cmp(&other.0.variant_index())
    }
}