Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Fix short hand struct doc #39459

Merged
merged 5 commits into from
Feb 8, 2017
Merged
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
24 changes: 24 additions & 0 deletions src/doc/book/structs.md
Original file line number Diff line number Diff line change
Expand Up @@ -117,6 +117,30 @@ fn main() {
}
```

Initialization of a data structure (struct, enum, union) can be simplified if
fields of the data structure are initialized with variables which has same
names as the fields.

```
#![feature(field_init_shorthand)]

#[derive(Debug)]
struct Person<'a> {
name: &'a str,
age: u8
}

fn main() {
// Create struct with field init shorthand
let name = "Peter";
let age = 27;
let peter = Person { name, age };

// Print debug struct
println!("{:?}", peter);
}
```

# Update syntax

A `struct` can include `..` to indicate that you want to use a copy of some
Expand Down
22 changes: 22 additions & 0 deletions src/doc/reference.md
Original file line number Diff line number Diff line change
Expand Up @@ -2757,6 +2757,28 @@ let base = Point3d {x: 1, y: 2, z: 3};
Point3d {y: 0, z: 10, .. base};
```

#### Struct field init shorthand

When initializing a data structure (struct, enum, union) with named fields,
allow writing `fieldname` as a shorthand for `fieldname: fieldname`. This
allows a compact syntax for initialization, with less duplication.

In the initializer for a `struct` with named fields, a `union` with named
fields, or an enum variant with named fields, accept an identifier `field` as a
shorthand for `field: field`.

Example:

```
# #![feature(field_init_shorthand)]
# struct Point3d { x: i32, y: i32, z: i32 }
# let x = 0;
# let y_value = 0;
# let z = 0;
Point3d { x: x, y: y_value, z: z };
Point3d { x, y: y_value, z };
```

### Block expressions

A _block expression_ is similar to a module in terms of the declarations that
Expand Down