Better support for tables

[damithc]

Current: we support GFMD syntax for tables
Suggestions for improvements:

• Ability to use more complex tables such as merged cells e.g., https://www.npmjs.com/package/markdown-it-multimd-table
• Ability to create a table based on content in a csv file
• Ability to sort columns
• Ability to specify larger amounts and different varieties of content for a cell (e.g., a panel within a cell)

[ang-zeyu]

just a note: markdown-it-multimd-table's multiline feature (using \ to continue lines) is wildly incompatible with our current process unfortunately, as we parse html before markdown. It would require a significant architectural change and breaking footnotes to accomodate it.
It is toggleable though, so if the other features have no conflict we could still look to replace gfmd table with it

[damithc]

I think asciidoc has a more powerful tables syntax. Of course unlikely we can reuse their parser but we can get some inspiration for the syntax.

Would using our own tag (like <puml>) to surround the table content allow us to use an entirely different syntax and parse it at a later stage? Not sure about the technical side but I had a feeling that @crphang was aiming for that kind of flexibility to use different syntax schemes for different components.

[ang-zeyu]

unfortunately not as well, as you'd end up still having to parse the html inside the tag. (since tables can contain html)
The ability to treat custom tags like script/style tags is more apt for an proprietary syntax, like puml.

[damithc]

unfortunately not as well, as you'd end up still having to parse the html inside the tag. (since tables can contain html)
The ability to treat custom tags like script/style tags is more apt for an proprietary syntax, like puml.

Yes, that's true.

[ang-zeyu]

possible with processing order change in #1403