I think you're confusing some things that really don't belong together:
A couple months ago, I submitted a PR to allow for extra content (extra JS and CSS) to be included in the HTML files. I didn't add any option to choose the markdown processor. You were supposed to choose the markdown processor in
ex_doc's config, which was already possible.
Some days later, I submitted a PR to allow for a custom markdown processor, given in the
:docs option of the
mix.exs file, which was rejected, because it did some sketchy things and @josevalim couldn't see a good case for that
At this point, it was already possible to use
protocol_ex package, by @OvermindDL1 uses it, for example: https://hexdocs.pm/protocol_ex/readme.html
Then, a couple of days ago, José reverted his position and decided that configuring the markdown processor from the
mix.exs file was not such a bad idea, and merged the changes himself. Then, after discussing it with José, I submitted a new PR that further simplifies the use of custom markdown processors. This is the one waiting to be merged. It adds absolutely no functionality, only simplifies the use of what's already there.
This PR doesn't touch anything related to the command line, and I don't think it's appropriate for it to do so. That's an orthogonal concern. The goal of this last PR was to simplify the way you'd use
ex_doc from Mix.