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/Rust

Structs

Syntax
Struct :
StructStruct
| TupleStruct

StructStruct :
struct IDENTIFIER Generics? WhereClause? ( { StructFields? } | ; )

TupleStruct :
struct IDENTIFIER Generics? ( TupleFields? ) WhereClause? ;

StructFields :
StructField (, StructField)* ,?

StructField :
OuterAttribute*
Visibility IDENTIFIER : Type

TupleFields :
TupleField (, TupleField)* ,?

TupleField :
OuterAttribute*
Visibility Type

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.

© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/reference/items/structs.html