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:

  1. // A function `age` which returns a `u32`.
  2. fn age() -> u32 {
  3.     15
  4. }
  6. fn main() {
  7.     println!("Tell me type of person you are");
  9.     match age() {
  10.         0             => println!("I'm not born yet I guess"),
  11.         // Could `match` 1 ... 12 directly but then what age
  12.         // would the child be? Instead, bind to `n` for the
  13.         // sequence of 1 .. 12. Now the age can be reported.
  14.         n @ 1  ... 12 => println!("I'm a child of age {:?}", n),
  15.         n @ 13 ... 19 => println!("I'm a teen of age {:?}", n),
  16.         // Nothing bound. Return the result.
  17.         n             => println!("I'm an old person of age {:?}", n),
  18.     }
  19. }

See also:

functions