There are many use cases. Here we introduce the following:
- The rows can be rolled `... | roll` (up) or `... | roll down`
- Columns can be rolled too (the default is on the `left`, you can pass `... | roll column --opposite` to roll in the other direction)
- You can `roll` the cells of a table and keeping the header names in the same order (`... | roll column --cells-only`)
- Above examples can also be passed (Ex. `... | roll down 3`) a number to tell how many places to roll.
Basic working example with rolling columns:
```
> echo '00000100'
| split chars
| each { str to-int }
| rotate counter-clockwise _
| reject _
| rename bit1 bit2 bit3 bit4 bit5 bit6 bit7 bit8
───┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────
# │ bit1 │ bit2 │ bit3 │ bit4 │ bit5 │ bit6 │ bit7 │ bit8
───┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────
0 │ 0 │ 0 │ 0 │ 0 │ 0 │ 1 │ 0 │ 0
───┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────
```
We want to "shift" three bits to the left of the bitstring (four in decimal), let's try it:
```
> echo '00000100'
| split chars
| each { str to-int }
| rotate counter-clockwise _
| reject _
| rename bit1 bit2 bit3 bit4 bit5 bit6 bit7 bit8
| roll column 3
───┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────
# │ bit4 │ bit5 │ bit6 │ bit7 │ bit8 │ bit1 │ bit2 │ bit3
───┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────
0 │ 0 │ 0 │ 1 │ 0 │ 0 │ 0 │ 0 │ 0
───┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────
```
The tables was rolled correctly (32 in decimal, for above bitstring). However, the *last three header names* look confusing.
We can roll the cell contents only to fix it.
```
> echo '00000100'
| split chars
| each { str to-int }
| rotate counter-clockwise _
| reject _
| rename bit1 bit2 bit3 bit4 bit5 bit6 bit7 bit8
| roll column 3 --cells-only
───┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────
# │ bit1 │ bit2 │ bit3 │ bit4 │ bit5 │ bit6 │ bit7 │ bit8
───┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────
0 │ 0 │ 0 │ 1 │ 0 │ 0 │ 0 │ 0 │ 0
───┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────
```
There we go. Let's compute it's decimal value now (should be 32)
```
> echo '00000100'
| split chars
| each { str to-int }
| rotate counter-clockwise _
| reject _
| roll column 3 --cells-only
| pivot bit --ignore-titles
| get bit
| reverse
| each --numbered { = $it.item * (2 ** $it.index) }
| math sum
32
```
