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Author SHA1 Message Date
Andrés N. Robalino
803826cdcd
90 degree table rotations (clockwise and counter-clockwise) (#3086)
Also for 180 degree is expected. Rotation is not exactly like pivoting (transposing)
for instance, given the following table:

```
> echo [[col1, col2, col3]; [cell1, cell2, cell3] [cell4, cell5, cell6]]
───┬───────┬───────┬───────
 # │ col1  │ col2  │ col3
───┼───────┼───────┼───────
 0 │ cell1 │ cell2 │ cell3
 1 │ cell4 │ cell5 │ cell6
───┴───────┴───────┴───────
```

To rotate it counter clockwise by 90 degrees, we can resort to first transposing (`pivot`)
them adding a new column (preferably integers), sort by that column from highest to lowest,
then remove the column and we have a counter clockwise rotation.

```
> echo [[col1, col2, col3]; [cell1, cell2, cell3] [cell4, cell5, cell6]] | pivot | each --numbered { = $it.item | insert idx $it.index } | sort-by idx | reverse | reject idx
───┬─────────┬─────────┬─────────
 # │ Column0 │ Column1 │ Column2
───┼─────────┼─────────┼─────────
 0 │ col3    │ cell3   │ cell6
 1 │ col2    │ cell2   │ cell5
 2 │ col1    │ cell1   │ cell4
───┴─────────┴─────────┴─────────
```

Which we can get easily, in this case, by doing:

```
> echo [[col1, col2, cel3]; [cell1, cell2, cell3] [cell4, cell5, cell6]] | rotate counter-clockwise
───┬─────────┬─────────┬─────────
 # │ Column0 │ Column1 │ Column2
───┼─────────┼─────────┼─────────
 0 │ col3    │ cell3   │ cell6
 1 │ col2    │ cell2   │ cell5
 2 │ col1    │ cell1   │ cell4
───┴─────────┴─────────┴─────────
```

There are also many powerful use cases with rotation, it makes a breeze creating tables with many columns, say:

```
echo 0..12 | rotate counter-clockwise | reject Column0
───┬─────────┬─────────┬─────────┬─────────┬─────────┬─────────┬─────────┬─────────┬─────────┬──────────┬──────────┬──────────┬──────────
 # │ Column1 │ Column2 │ Column3 │ Column4 │ Column5 │ Column6 │ Column7 │ Column8 │ Column9 │ Column10 │ Column11 │ Column12 │ Column13
───┼─────────┼─────────┼─────────┼─────────┼─────────┼─────────┼─────────┼─────────┼─────────┼──────────┼──────────┼──────────┼──────────
 0 │       0 │       1 │       2 │       3 │       4 │       5 │       6 │       7 │       8 │        9 │       10 │       11 │       12
───┴─────────┴─────────┴─────────┴─────────┴─────────┴─────────┴─────────┴─────────┴─────────┴──────────┴──────────┴──────────┴──────────
```
2021-02-22 06:56:34 -05:00