Structs

Like tuples, Struct can also be destructured by matching:

struct Foo {
    x: (u32, u32),
    y: u32,
}
#[rustfmt::skip]
fn main() {
    let foo = Foo { x: (1, 2), y: 3 };
    match foo {
        Foo { x: (1, b), y } => println!("x.0 = 1, b = {b}, y = {y}"),
        Foo { y: 2, x: i }   => println!("y = 2, x = {i:?}"),
        Foo { y, .. }        => println!("y = {y}, other fields were ignored"),
    }
}

This slide should take about 4 minutes.

• Change the literal values in foo to match with the other patterns.
• Add a new field to Foo and make changes to the pattern as needed.
• The distinction between a capture and a constant expression can be hard to spot. Try changing the 2 in the second arm to a variable, and see that it subtly doesn’t work. Change it to a const and see it working again.