Show foldcolumn only when one or more folds are closed

[yoplat]

Screen.Recording.2023-10-09.at.16.57.39.mov

This is what I've been able to do to make it happen but I don't know why but it adds spacing to the left instead of the right. I'm looking for a way to enable the foldcolumn only when there is at least one fold closed.

[luukvbaal]

Not exactly sure what you want, this segment might be closer:

{
  text = {
    function() return "%=" end,
    " ",
    builtin.foldfunc
  },
  condition = {
    true, 
    function(args) return args.fold.width > 0 end,
    true,
  }
},

[luukvbaal]

Also, is the condition for builtin.foldfunc even necessary?
If you set 'foldcolumn' to "auto" it should hide automatically when there are no folds in the current buffer.

[luukvbaal]

I've added args.fold.width in 826aed3 which you might use as the condition for the whitespace in your config (still not exactly sure that that is what you want).

[yoplat]

Also, is the condition for builtin.foldfunc even necessary? If you set 'foldcolumn' to "auto" it should hide automatically when there are no folds in the current buffer.

It's not that I want to disable it if there are no folds in the buffer (not specifically), I want to disable it even if there are folds available in the buffer but there isn't any closed. I want to show the foldcolumn only if there is at least one fold closed. This is because I normally don't use folds, but if I fold something I want to be able to see it in the statuscolumn.

[luukvbaal]

Detecting whether the current window contains any closed folds is unfortunately not currently possible through the neovim API without looping over each buffer line(neovim/neovim#19226). Not something I would recommend to do inside the statuscolumn callback.

[Pedro Ferrari]

Hi @luukvbaal. I'm using the solution you posted. As it can be seen in the image below my fold currently looks like >291 class.... I have two questions:

1. Is possible to get the > fold symbol in the current line to share the linenr (white) highlight? (only for the current line)
2. I like the fact that there is minimal separation/padding between the fold symbol and the line number but for the current line I would like to add a whitespace such that I get > 291 instead of >291 (while keeping for the other lines the > 3). Dunno if this is possible.

Thanks in advance for the help!

[luukvbaal]

1. See :h hl-CursorLineFold. The builtin fold column segment should follow that highlight group when 'cursorline' is set.
2. I'm not sure, the picture you posts shows a misaligned foldcolumn. The foldcolumn should be a single column no, it would look weird with a foldcolumn that has a background highlight defind.
   If that is what my snippet yields it is erroneous, perhaps adding a %= segment isn't a good idea. Simply adding padding (conditional on whether there is a foldcolumn) before the line number could be done like so:

{
  text = {
    builtin.foldfunc,
    " ",
  },
  condition = {
    true,
    function(args) return args.fold.width > 0 end,
  }
}

[luukvbaal]

Closing this, original issue kind of necessitates an addition to the neovim API.

[Pedro Ferrari]

1. Great. Worked perfectly
2. What I meant was whether is possible to have a different padding behavior for the current/cursor line. I use relative numbers so relativeline numbers tend to be small (between 1-52) except for the current line (which shows the actual line number, in the image 291). I like the way fold + line numbers look in general (i.e minimal space between the fold and the line nr as in > 3 class RolCustomApp) but was wondering whether a condition could be added such that if we are on the current line an extra padding can be added between the fold and the line number: > 291 instead of >291.

[luukvbaal]

@petobens I mean a conditional whitespace segment for the current line would be:

{
  text = { " " },
  condition = { function(args) return args.relnum == 0 end }
},

But IDK if you can make that work properly with alignment.

[Pedro Ferrari]

Mmm doing:

        {
            text = {
                function()
                    return '%='
                end,
                builtin.foldfunc,
            },
            auto = true,
        },
        {
            text = {
                function(args)
                    return (args.relnum == 0) and ' ' or ''
                end,
            },
        },

is basically equivalent to simply adding a whitespace characters after the foldfunc as far as I can tell:

        {
            text = {
                function()
                    return '%='
                end,
                builtin.foldfunc,
                ' ',
            },
            auto = true,
        },

If this is true then I have no further options right?

[luukvbaal]

is basically equivalent to simply adding a whitespace characters after the foldfunc as far as I can tell:

Yeah probably because the builtin line number segment starts with a %=, any preceding whitespace is aligned also on non-cursor lines.

If this is true then I have no further options right?

Yeah unfortunately I don't think any non-trivial segment/option this plugin provides can do what you're looking for. Probably doable if you resort to custom segments that add their own padding rather than relying on the %= separator item...