New upstream version 1.38.0+dfsg1

[rustc.git] / src / doc / rust-by-example / src / flow_control / match / binding.md

# Binding

Indirectly accessing a variable makes it impossible to branch and use that
variable without re-binding. `match` provides the `@` sigil for binding values to
names:

```rust,editable
// A function `age` which returns a `u32`.
fn age() -> u32 {
    15
}

fn main() {
    println!("Tell me what type of person you are");

    match age() {
        0             => println!("I'm not born yet I guess"),
        // Could `match` 1 ... 12 directly but then what age
        // would the child be? Instead, bind to `n` for the
        // sequence of 1 .. 12. Now the age can be reported.
        n @ 1  ..= 12 => println!("I'm a child of age {:?}", n),
        n @ 13 ..= 19 => println!("I'm a teen of age {:?}", n),
        // Nothing bound. Return the result.
        n             => println!("I'm an old person of age {:?}", n),
    }
}
```

### See also:
[functions]

[functions]: ../../fn.md