completing-read a list of keywords

[Daniele Nicolodi]

Hello,

I am trying to come up with a solution to be able to use completing-read
to prompt the user for a comma (or space) separated list of words.
Unfortunately the completion framework is still rather impenetrable to
me. Does anyone have pointers to relevant examples and documentation?

org-mode has something similar for the completion of tags. But I haven't
been able to understand what the code does.

Thank you!

Best,
Dan