This Pandoc Lua filter allows to convert lists of lists (bullet lists and/or ordered lists) into tables. This makes it easier to type long tables and tables with "complicated" content because you don't need to draw any ASCII art.
The filter can also convert tables to lists of lists, allowing full roundtripping.
This document describes filter version 202010012000.
Don't modify pandoc-list-table.lua directly!
The filter is written in MoonScript which must be compiled to Lua with the moonc program to be used with Pandoc. If you want to do a pull request, or just hack on the filter, you should edit the pandoc-list-table.moon file, install MoonScript, then compile the filter code to Lua with moonc pandoc-list-table.moon, then check that your modifications work by running pandoc on suitable input with pandoc-list-table.lua specified as a Lua filter.
With Pandoc version 2.10 Pandoc's internal representation of tables changed from the earlier simple model to a model which allows "complex" tables more similar to HTML tables (colspan/rowspan etc.), so that existing filters written to work with the old simple Table object don't work with Pandoc 2.10.0 and Pandoc 2.10.1 After Pandoc version 2.10.1 the Lua filter engine supports, as a compatibility measure, a new SimpleTable object type similar to the old simple Table object, and provides functions to convert between SimpleTable objects and the new "complex" Table type. As of Pandoc 2.10.1 Pandoc's Markdown reader and writer do as yet not have any syntax supporting the new "complex" table features, and since it is not clear how this filter might support complex tables no support for the complex Table object type has been implemented in this filter either.
Due to the changed table model in Pandoc 2.10 this filter does not work with
Pandoc versions 2.10.0 and 2.10.1 inclusive. As of filter version 20201001
(that's YYYYMMDD!) there is a check in place which uses the SimpleTable
(see also the SimpleTable pull request)
constructor if it exists and throws an error if the PANDOC_VERSION >= 2.10.0
but SimpleTable does not exist. Thus the filter should work both with nightlies
where SimpleTable exists and with the next release of Pandoc. If SimpleTable
exists the table2lol implementation now tries to convert complex Table objects
to SimpleTable objects, throwing an error with a hopefully helpful message if
conversion fails, and at the other end the lol2table implementation converts a
SimpleTable to a complex Table before returning (and also throws an error with a
hopefully helpful message in the unlikely event that such a conversion fails.)
This should mean that when Pandoc's readers and writers start to support the new complex Table features this filter should still work unless you try to convert tables actually using those features to lists. In the future this filter may come to support at least some complex Table features along the lines suggested in Issue #1, but don't hold your breath for it!
In this README a distinction is made between the following terms:
-
complicated content
Table cell content which is hard or impossible to represent in the "ASCII art" table syntaxes of Pandoc's Markdown.
-
complex Table
The new Table object type in the Lua filter engine from Pandoc 2.10 and on, which supports various HTML-like table features such as colspans and rowspans. This filted does as of its version 20201001 not support these features.
-
simple Table
The old Table object type in the Lua filter engine before Pandoc 2.10, which did not support the new "complex" table features. This filter supports versions of Pandoc using this older Table object type.
-
SimpleTable
The compatibility SimpleTable object type, similar to the old simple Table object type supported by the Lua filter engine in versions of Pandoc later than 2.10. This filter uses this object type when available.
Obviously it would be dysfunctional if all lists of lists were converted to tables. Hence you must tell the filter that you want to convert a given list of list to a table by wrapping the list in a div with the class lol2table (short for "list-of-lists-to-table":
:::lol2table
* - foo
- bar
- baz
* - + tic
+ pic
- + tac
+ pac
:::When running this through pandoc with the filter enabled and with markdown as output format it is replaced with this:
+---------+---------+-----+
| foo | bar | baz |
+=========+=========+=====+
| - tic | - tac | |
| - pic | - pac | |
+---------+---------+-----+Note how each item in the top level list becomes a table row and each item in the second level list becomes a table cell, while third level list remain lists. Note also that the filter handles the situation where there are only two items in the second second-level list: if any rows are shorter than the longest row they are padded with empty cells towards the end.
To turn a list of lists into a headerless table just include the class no-header (or noheader) on the wrapping div:
::: {.lol2table}
Table with header
1. 1. foo
2. bar
3. baz
2. 1. tic
2. tac
3. toc
:::
::: {.lol2table .no-header}
Table without header
1. 1. foo
2. bar
3. baz
2. 1. tic
2. tac
3. toc
:::foo bar baz
----- ----- -----
tic tac toc
: Table with header
----- ----- -----
foo bar baz
tic tac toc
----- ----- -----
: Table without headerThe previous example also shows how to set a caption on the table: just include a paragraph with the caption text inside the div.
To specify the alignment of the table columns set an attribute align on the div. Its value should be a comma separated "list" (and I mean comma separated, not comma-and-whitespace!) of any of the letters d l c r (for AlignDefault, AlignLeft, AlignCenter, AlignRight respectively):
::: {.lol2table align="l,c,r"}
* - foo
- bar
- baz
* - + tic
+ pic
- + tac
+ pac
:::+---------+---------+-----+
| foo | bar | baz |
+:========+:=======:+====:+
| - tic | - tac | |
| - pic | - pac | |
+---------+---------+-----+Likewise to specify the relative width of columns include an attribute widths on the div. Its value should be a comma-separated (again really comma separated!) "list" of integers between 0 and 100, where each integer is the percentage of the available total width which should be the width of the respective column:
::: {.lol2table widths="20,40,10"}
* - foo
- bar
- baz
* - + tic
+ pic
- + tac
+ pac
:::+-------------+---------------------------+------+
| foo | bar | baz |
+=============+===========================+======+
| - tic | - tac | |
| - pic | - pac | |
+-------------+---------------------------+------+Naturally you can combine the two:
::: {.lol2table align="l,c,r" widths="20,40,10"}
* - foo
- bar
- baz
* - tic
- tac
:::---------------------------------------------------
foo bar baz
-------------- ---------------------------- -------
tic tac
---------------------------------------------------If you specify more alignments or widths than there are columns the extra alignments/widths will be ignored.
If you specify fewer alignments than there are columns the list of alignments is padded to the right length with copies of the rightmost alignment actually specified. If you specify fewer widths than there are columns the list of widths is padded to the right length with zeroes. This should cause Pandoc to distribute the remaining width between them.
To convert a table into a list of lists you wrap it in a div with the class table2lol:
:::table2lol
|foo|bar|baz
|---|---|---
|tic|tac|toc
:::0. 1. foo
2. bar
3. baz
1. 1. tic
2. tac
3. tocNote that the resulting lists always are numbered lists and that if there was a header row the numbering of the top-level list starts at zero.
If you include a class keep-div (or keepdiv) on the div the result will also be wrapped in a div, designed to make roundtripping easier:
::: {#alpha .lol2table .keep-div}
1. 1. foo
2. bar
3. baz
2. 1. tic
2. tac
3. toc
:::
::: {#beta .table2lol .keep-div}
foo bar baz
----- ----- -----
tic tac toc
:::::: {#alpha .maybe-table2lol .keep-div}
foo bar baz
----- ----- -----
tic tac toc
:::
::: {#beta .maybe-lol2table .keep-div align="l,l,l" widths="0,0,0"}
0. 1. foo
2. bar
3. baz
1. 1. tic
2. tac
3. toc
:::Benct Philip Jonsson bpjonsson+pandoc@gmail.com
This software is Copyright (c) 2020 by Benct Philip Jonsson.
This is free software, licensed under:
The MIT (X11) License