prelude::ops

Every operator is a trait method: a + b is Add, a == b is Eq, a < b is Lt, and format("%v", x) uses Show. The primitive types implement the ones that make sense for them. Implement a trait for your own class or enum to give it the operator:

class Money {
    pub cents: int,
}

impl Add for Money {
    pub fn add(Money a, Money b) -> Money {
        return new Money(a.cents + b.cents);
    }
}

Num and Integral bundle the arithmetic traits so generic code can ask for “any number” (fn sum<T: Num>(…)). #[derive(Eq, Ord, Show)] writes the common instances for you; see Macros. The rules for each operator are in Operators.

Built into the compiler.

Traits#