>>> template `^`(x: int): BackwardsIndex
Builtin roof operator that can be used for convenient array access. a[^x] is a
shortcut for a[a.len-x].

let
  a = [1, 3, 5, 7, 9]
  b = "abcdefgh"

echo a[^1] # => 9
echo b[^2] # => g