Persistent folding: how to use space-style to hide a particular attribute?

General
10

So I tried this to fold on page loads. Works well, except editor.getCursor() returns nil. So after the page loads, the cursor is not set by SB to its correct position, but remains at the last line that was folded. I don’t understand when and how SB sets the cursor position (to what it was when this page was last visited). Help appreciated.

event.listen{
  name = "editor:pageLoaded",
  run = function()
    local text = editor.getText()
    if not text then
      return
    end
  
    -- Save cursor position
    local originalCursor = editor.getCursor()
  
    local lineNum = 0
    for line in (text .. "\n"):gmatch("(.-)\n") do
      lineNum = lineNum + 1
  
      -- Simple substring match
      if line:find("[folded: true]", 1, true) then
        -- Move cursor to the line so the folding can be done
        editor.moveCursorToLine(lineNum, 1, false)
        
        -- Fold the block at cursor
        editor.fold()
      end
    end

    -- Restore cursor
    if originalCursor then
      editor.setCursor(originalCursor)
    end
  end
}