Structs

A struct also allows for grouping multiple values of different types. Unlike tuples, we can also name each field.

Note: The usage of field here refers to each element of the struct and is unrelated to the field type of Noir.

Defining a struct requires giving it a name and listing each field within as <Key>: <Type> pairs:

struct Animal {
    hands: Field,
    legs: Field,
    eyes: u8,
}

An instance of a struct can then be created with actual values in <Key>: <Value> pairs in any order. Struct fields are accessible using their given names:

fn main() {
    let legs = 4;

    let dog = Animal {
        eyes: 2,
        hands: 0,
        legs,
    };

    let zero = dog.hands;
}

Structs can also be destructured in a pattern, binding each field to a new variable:

fn main() {
    let Animal { hands, legs: feet, eyes } = get_octopus();

    let ten = hands + feet + eyes as u8;
}

fn get_octopus() -> Animal {
    let octopus = Animal {
        hands: 0,
        legs: 8,
        eyes: 2,
    };

    octopus
}

The new variables can be bound with names different from the original struct field names, as showcased in the legs --> feet binding in the example above.