feat(treesitter): playground improvements

- Render node ranges as virtual text
- Set filettype=query. The virtual text is to avoid parsing errors.
- Make sure highlights text is always in view.

1 files changed, 10 insertions, 3 deletions

diff --git a/runtime/lua/vim/treesitter.lua b/runtime/lua/vim/treesitter.lua
index 96b1e24ba9..a15d3ec23c 100644
--- a/runtime/lua/vim/treesitter.lua
+++ b/runtime/lua/vim/treesitter.lua
@@ -411,6 +411,7 @@ function M.show_tree(opts)
   vim.bo[b].buflisted = false
   vim.bo[b].buftype = 'nofile'
   vim.bo[b].bufhidden = 'wipe'
+  vim.bo[b].filetype = 'query'
 
   local title = opts.title
   if not title then
@@ -425,9 +426,6 @@ function M.show_tree(opts)
 
   pg:draw(b)
 
-  vim.fn.matchadd('Comment', '\\[[0-9:-]\\+\\]')
-  vim.fn.matchadd('String', '".*"')
-
   a.nvim_buf_clear_namespace(buf, pg.ns, 0, -1)
   a.nvim_buf_set_keymap(b, 'n', '<CR>', '', {
     desc = 'Jump to the node under the cursor in the source buffer',
@@ -467,6 +465,15 @@ function M.show_tree(opts)
         end_col = math.max(0, pos.end_col),
         hl_group = 'Visual',
       })
+
+      local topline, botline = vim.fn.line('w0', win), vim.fn.line('w$', win)
+
+      -- Move the cursor if highlighted range is completely out of view
+      if pos.lnum < topline and pos.end_lnum < topline then
+        a.nvim_win_set_cursor(win, { pos.end_lnum + 1, 0 })
+      elseif pos.lnum > botline and pos.end_lnum > botline then
+        a.nvim_win_set_cursor(win, { pos.lnum + 1, 0 })
+      end
     end,
   })