Tracking issue for Option::xor

[andre-vm]

Today I got myself in a situation in which I had two Option<T> values, and I wanted to return the only one that was Some. If both of them were Some, then I'd rather return None. I think it would be perfect to have a xor method, very similar to the or method:

impl<T> Option<T> {

    //...

    fn xor(self, optb: Option<T>) -> Option<T> {
        match (&self, &optb) {
            (&Some(_), &None) => self,
            (&None, &Some(_)) => optb,
            _ => None,
        }
    }
}

I think that would solve my problem nicely, and could be useful for a lot of people as well.

[clarfonthey]

There should also be an xor_else method, similar to or_else.

[ollie27]

There would be no point in a xor_else because you always have to evaluate the second argument.

[clarfonthey]

…good point. Never mind, then.

[andre-vm]

Implemented on #50553.

[clarfonthey]

@Milack27 You actually need to keep this issue open as a tracking issue. It hasn't been stabilised yet, so, it can only be used with #![feature(option_xor)] at the moment.

If you could rename this issue to "Tracking issue for Option::xor" it would also help make that clear.