slice_patterns
The tracking issue for this feature is: #62254
The slice_patterns
feature gate lets you use ..
to indicate any number of
elements inside a pattern matching a slice. This wildcard can only be used once
for a given array. If there's an pattern before the ..
, the subslice will be
matched against that pattern. For example:
#![feature(slice_patterns)] fn is_symmetric(list: &[u32]) -> bool { match list { &[] | &[_] => true, &[x, ref inside @ .., y] if x == y => is_symmetric(inside), &[..] => false, } } fn main() { let sym = &[0, 1, 4, 2, 4, 1, 0]; assert!(is_symmetric(sym)); let not_sym = &[0, 1, 7, 2, 4, 1, 0]; assert!(!is_symmetric(not_sym)); }