Re: org table proposal: merge and split cells in org-tables

[Ihor Radchenko <yantar92@posteo.net>]

Uwe Brauer <oub@mat.ucm.es> writes:

> In a conversation with Ihor Radchenko it was considered as being helpful
> to provide a table in which cells are merged and split.

We should consider this idea seriously as this and related features are
being requested frequently in the community. I recall the following
contexts:

- Support merging cells when exporting to LaTeX tables
- Text filling inside tables

> Here is one
>
> +--------+-------------------------------------------------+
> | Region |                      Sales                      |
> |        +-------------+-----------+-----------+-----------+
> |        |      Q1     |    Q2     |    Q3     |    Q4     |
> |        +-------+-----+-----+-----+-----+-----+-----+-----+
> |        | foo   | bar | foo | bar | foo | bar | foo | bar |
> +--------+-------+-----+-----+-----+-----+-----+-----+-----+
> | North  | 350   |  46 | 253 |  34 | 234 |  42 | 382 |  68 |
> +--------+-------+-----+-----+-----+-----+-----+-----+-----+
> | South  | 462   |  84 | 511 |  78 | 435 |  45 | 534 |  89 |
> +--------+-------+-----+-----+-----+-----+-----+-----+-----+

This essentially suggests supporting table.el syntax natively. Or maybe
extending it by mixing with native Org tables.

In terms of syntax, adding cell boundary support might be simply a
question of allowing +----+ in Org tables. It will not break anything as
we already parse +-----+ as table.el tables.

At lower level of org-element representation, we do not need to change
much either. table-row elements are already not tied to a fixed number
of cells in every row. And we may extend table-row 'rule type to define
the "+----+   +   +---+--+" cell boundaries.

However, in order to support merging cells, one needs to rework Org in a
number of places. At least:

1. org-element parser and interpreter
2. org-table.el in its totality
3. export backends
4. table formulas; in particular, cell references
5. update syntax document

> Or better

> ------------------------------------------------------------
> | Region |                      Sales                      |
> |        ---------------------------------------------------
> |        |      Q1     |    Q2     |    Q3     |    Q4     |
> |        ---------------------------------------------------
> |        | foo   | bar | foo | bar | foo | bar | foo | bar |
> ------------------------------------------------------------
> | North  | 350   |  46 | 253 |  34 | 234 |  42 | 382 |  68 |
> ------------------------------------------------------------
> | South  | 462   |  84 | 511 |  78 | 435 |  45 | 534 |  89 |
> ------------------------------------------------------------

This will clash with horizontal-rule syntax. Not acceptable. Also,
parsing this kind of table will be significantly harder programatically.

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
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