I think it would be very helpful to allow -1 to select the last array element.
It should only be used by `select` and `#`, not `param` (to not break backward compatibility):
```
_arr = [1,2,3];
_arr#-1 // return 3
```
Alternatively, maybe using negative numbers should be just modded in general? (using: `count - (-index - count) % count`, where `count > 0` and `index < 0`)
e.g.:
```
_arr = [0, 1, 2, 3, 4];
_arr#-1; //4
_arr#-2; //3
_arr#-103 //2
```