Mermaid output

[jonascarpay]

GitHub markdown now supports inline Mermaid flowchart diagrams:

flowchart LR
    foo --> bar
    bar --> baz

If calligraphy were to output Mermaid directly, you could easily e.g. include call graphs in your documentation or PRs. It shouldn't be too tricky, and it seems extremely useful.

[Kleidukos]

I have been looking for something like this for a long time!

An idea that I'd love to join with it would be to mark identifiers with a Haddock metadata so that only them are picked by Calligraphy. This would be useful to only show "domain-level" operations to non-technical people, with the beautiful Mermaid output. :)

[jonascarpay]

Oh, that's a neat idea! I don't really know or remember off the top of my head how much Haddock makes its way into HIE output, do you have any idea?

[Kleidukos]

Unfortunately the .hie files don't hold any documentation, it's all in .hi files according to @fendor

[Kleidukos]

@jonascarpay I'll try to give a stab to the Mermaid backend! I'll use the tasty framework to have unit and golden tests :+1:

[jonascarpay]

Nice! Let me know if you need help/input on anything. The trickiest thing is probably untangling the graphviz-specific parts and the more general parts of the rendering logic. Maybe it's useful to create an intermediate representation that's easy to render for both mermaid and graphviz?

[Kleidukos]

Yes, I'm going to do some internal refactoring. Ideas welcome when it comes to internal representations of flowcharts, I'm not exactly an expert in the field :)

[jonascarpay]

I started sketching out an internal representation, but I'm now so far along I might as well get it compiling and to a point where you should be able to adapt it pretty easily to a mermaid renderer. PR coming soon, I hope I didn't accidentally duplicate any of your efforts.

[Kleidukos]

Nope! I'm very eager to learn from you as well :)