Configurable link rendering

[dosmanak]

Relates to issue #3 Improve link pretty printing.

The markdown works with three kinds of links [pandoc docs](https://pandoc.org/MANUAL.html#links-1):
* automatic links just turn an url into clickable link <https://pandoc.org/MANUAL.html#automatic-links>
* [inline links](https://pandoc.org/MANUAL.html#inline-links) are written as part of text body
* [reference links][1]

[1]: https://pandoc.org/MANUAL.html#reference-links "Reference links title is shown on hover"

The markdown works with three kinds of links pandoc docs:

• automatic links just turn an url into clickable link https://pandoc.org/MANUAL.html#automatic-links
• inline links are written as part of text body
• reference links

Patat uses ANSI terminal, so it must render the links verbatim. Yet many terminal emulators support OSC-8

I propose to make link rendering more configurable.

Automatic links can stay as is.

Inline and Reference links should be rendered inline using terminal hyperlink.

Reference links should be rendered in slide footer (current behavior) or in extra slide at the and of the presentation.

Or the rendering could be more configurable.

Perhaps some kind of patat config should control the behavior:

patat:
  links:
    inline: <footer|osc8|extraslide>
    reference: <footer|osc8|extraslide>

[jaspervdj]

Thanks for opening this issue!

Using OSC-8 is a good suggestion. I would lean towards the configuration:

patat:
  links:
    osc8: true

Then we can add footer/extraslide later without impacting the osc8 setting.

Unfortunately there is no way to auto-detect if the terminal emulator supports this, so false would be a better default.

Maybe it's time for patat to try and detect the terminal it's running on (e.g. data Terminal = Kitty | Alacritty | ... | Unknown) and then we can enable certain features based on that. But that's sort of a separate piece of work that could go on top of this.

So starting with just the osc8 settings seems like a good first step.

[dosmanak]

Thank you for fast response. I understand the need to introduce features individually but your proposal of config syntax does not reflect intended possibility to render inline and reference link differently although I understand it is perhaps against the design of markdown.

Nevertheless the provided example implies that single link could be rendered using all available methods when declared like

patat:
  links:
    osc8: true
    footer: true
    extraslide: true

I am not sure if such possibility is reasonable. If different methods for inline and reference links are not possible/wanted I think the config should by represented by value, not key, i.e.

patat:
   linkRender: <footer|osc8>

where footer is current behavior showing links at bottom of each slide, so it will become default and osc8 is to be implemented.
extraslide could be implemented later if ever.

[jaspervdj]

That makes sense. I was looking at this a little and found that shortcut reference links were actually not rendered nicely by default, and fixed that in e77899f.

What about the following configuration:

  patat:
    links:
      references: <inline|bottom|appendix>
      osc8: <true|false>

The references value determines where we show references links: inline (which sort of removes the reference, making them the same as existing inline links), at the bottom of the slide, or on an extra appendix slide.

Then, we have the independent osc8 setting. If this is true:

• For inline links, we drop the URL make them clickable:

  [foo](http://example.com) becomes [foo]

• For reference links, we make the titles and references clickable:

  [foo][ref] becomes [foo][ref]
  [foo] becomes [foo]

I chose bottom over footer because I think of the last line on the terminal with the slide number as the footer.

Similarly I think appendix seems more accurate than extraSlide. This may require more configuration... you could want the references at the end of each "chapter", or at the very end. I'll probably leave this out for now.

[jaspervdj]

#185 adds support for the osc8 setting. This just determines whether or not links are made clickable. Link placement configuration will follow in a separate PR.