[WIP] Replace Parsedown with CommonMark

[hason]

• Add support for a new Converter base class for CommonMark mnapoli/FrontYAML#10
• tests

[mnapoli]

Thank you for the PR. Have also a look at #69 (comment) I did try to migrate to CommonMark, but it doesn't support Markdown Extra. I'm afraid it might be blocking if we want to avoid breaking BC (and green tests).

[bobmulder]

I am just screening through the couscous-repository. Why would we want to change the markdown-parser? I see that parsedown can handle extensions (https://github.com/erusev/parsedown/wiki/Tutorial:-Create-Extensions) so we could add ours if we want to expand it...

[mnapoli]

CommonMark parses the text into some sort of AST (abstract syntax tree), i.e. a model of the whole document. That means we can much more easily manipulate it. For example it would be very easy to extract titles to create a summary.

[bobmulder]

Okay, thanks for the update. I'll look at CommonMark instead of Parsedown ;)

[colinodell]

Thank you for the PR. Have also a look at #69 (comment) I did try to migrate to CommonMark, but it doesn't support Markdown Extra.

FYI it does support GFM now, and has a bunch of other useful extensions that might be helpful: https://commonmark.thephpleague.com/1.4/extensions/overview/#included-extensions

[mnapoli]

@colinodell thanks for the update, love your work.

I'd love to switch to CommonMark, I haven't much time to spend on the migration for now but I'll definitely keep that in my todo list.