Treesitter Concealing

[jgollenz]

@kristijanhusak could you please tell me if I understand correctly:

With this we could do link concealing via treesitter, but the org-grammar does not detect links, so we are out of luck anyway?

[kristijanhusak]

We are using treesitter concealing for some time now: 156d8c5

Or are you talking about something else?

[kristijanhusak]

We are not using built in conceal predicate, but our own: https://github.com/nvim-orgmode/orgmode/blob/master/queries/org/markup.scm#L14-L15, and this is where concealing happens: https://github.com/nvim-orgmode/orgmode/blob/master/lua/orgmode/colors/markup_highlighter.lua#L292-L302

I'm not sure how we could tackle that issue, since concealing reduces the width of the content.
And since we would need to do this only in the headline, it would be tricky.

[jgollenz]

I see. Thanks for clarification 👍

Somewhere I have a poc of just inserting whitespace after the headline to equal out the width, but like I said, this will then mess with the width when no concealing is happening (e.g. because it is turned off or the file is not viewed in neovim). No good. In theory, we could go through the headline content and count all concealed characters with synconcealed, which gives the width we need to equal out. But we cannot touch the actual 'source' line, because conceal also doesn't do that. Some sort of virtual text that interacts with the line 'as if' if were really inserted into the buffer would be ideal in my opinion.

Could you elaborate on what the tricky part is regarding only doing it on a headline?

[kristijanhusak]

Could you elaborate on what the tricky part is regarding only doing it on a headline?

Actually this might not be so tricky as I thought. We have the line number of the link, so we can just check if the line starts with asterisk, somewhere around here.
I'm assuming this issue happens also for any markup that is concealed, not only links, since headlines can also have italic or underline markup.
I never used extmarks to do anything with virtual lines, but I guess you can give it a try. You an figure out the length of the concealed text in the code I linked above, depending on if it's a link with or without alias, or a markup.

[jgollenz]

this issue happens also for any markup that is concealed

Yes, strikethrough was what got me into investigating it this time. That's why I think synconcealed would be great, as it enables us from treating different cases of concealing the same, just count the concealed chars. Thinking about virtual text: perhaps we could abuse the overlay mode for this. Instead of just 'inserting' some spaces into the line to balance concealing out, we can just overlay the tags part of the headline (tags + actual spaces) with virtual text (tags + actual spaces + virtual spaces).

Won't start on this now though, I'm a bit busy atm

[jgollenz]

398689616 could be interesting here