Could the runtools extension and Jupyter Book share the same hide_input metadata?

[mwouts]

Hello @jcb91, @juhasch, thank you for your work on the runtools extension, which to my knowledge was the only way to filter input/outputs from Jupyter notebooks for a long time!

I see that Jupyter Book now also offers this functionality, with the same metadata name, but it's implemented using tags rather than key/value metadata. Would you be interested in discussing with us (and @choldgraf, the author of Jupyter Book) the opportunity to agree on a common standard? We've started chatting on this at mwouts/jupytext#337, but maybe we can continue here. In particular I'd like to know

• what you think of using tags versus key/values
• if you are aware of any other project that can be used to include/hide/remove cell input or output (I am aware of hide_input_all, which sets a hide_input metadata at the notebook level)
• and if you consider runtools as evolvable, or not.