具有多个特征的泛型类型

Question

Here is my code :

struct Node<T: PartialEq & PartialOrd>
{
    left: Box<Option<Node<T>>>,
    right: Box<Option<Node<T>>>,
    value: Option<T>,
}

I want to force the T generic type to implement both the PartialEq and the PartialOrd traits. I can't found the synthax to do this (the & char not being the one I look for). Thanks for helping me.

Answer 1

The syntax is + :

struct Node<T: PartialEq + PartialOrd> {
    left: Option<Box<Node<T>>>,
    right: Option<Box<Node<T>>>,
    value: Option<T>,
}

I would also recommend changing Box<Option<U>> to Option<Box<U>> . This can be represented more efficiently ( None doesn't require an allocation, and is in fact represented as a null pointer).