Structs
A struct is a nominal struct type defined with the keyword struct
.
An example of a struct
item and its use:
#![allow(unused_variables)]
fn main() {
struct Point {x: i32, y: i32}
let p = Point {x: 10, y: 11};
let px: i32 = p.x;
}
A tuple struct is a nominal tuple type, also defined with the keyword
struct
. For example:
#![allow(unused_variables)]
fn main() {
struct Point(i32, i32);
let p = Point(10, 11);
let px: i32 = match p { Point(x, _) => x };
}
A unit-like struct is a struct without any fields, defined by leaving off the list of fields entirely. Such a struct implicitly defines a constant of its type with the same name. For example:
#![allow(unused_variables)]
fn main() {
struct Cookie;
let c = [Cookie, Cookie {}, Cookie, Cookie {}];
}
is equivalent to
#![allow(unused_variables)]
fn main() {
struct Cookie {}
const Cookie: Cookie = Cookie {};
let c = [Cookie, Cookie {}, Cookie, Cookie {}];
}
The precise memory layout of a struct is not specified. One can specify a
particular layout using the repr
attribute.