Progressively render cells from script files

[jtpio]

Moving the discussion from #330 (comment) to a new issue.

Similar to #133 the notebook created from script files could take advantage of inline cell delimiters (%%, In [1]:), and benefit from the future async capabilities by creating multiple cells instead of one:

https://github.com/QuantStack/voila/blob/344b4ff4f9d012ada2d984221a78dd8ec93d8241/voila/handler.py#L161

[flaviomorelli]

The challenge is how to take all the different formats generated by tools like jupytext into account (e.g. percentage script, markdown).

The reads and writes methods from TextNotebookConverter in Jupytext show examples of how to handle the parsing. The question is how to integrate the functionality into voila without having a jupytext dependency.

[jtpio]

Thanks @flaviomorelli for investigating and the pointers 👍

[maartenbreddels]

I am not sure this is a voila responsibility, we'd be reproducing Jupytext right?