1 files changed, 52 insertions, 1 deletions
diff --git a/runtime/ftplugin/help.lua b/runtime/ftplugin/help.lua
index 8d991be0e4..a6169a1d9d 100644
--- a/runtime/ftplugin/help.lua
+++ b/runtime/ftplugin/help.lua
@@ -31,5 +31,56 @@ vim.keymap.set('n', 'gO', function()
   require('vim.vimhelp').show_toc()
 end, { buffer = 0, silent = true })
 
-vim.b.undo_ftplugin = (vim.b.undo_ftplugin or '') .. '\n exe "nunmap <buffer> gO"'
+-- Add "runnables" for Lua/Vimscript code examples.
+---@type table<integer, { lang: string, code: string }>
+local code_blocks = {}
+local tree = vim.treesitter.get_parser():parse()[1]
+local query = vim.treesitter.query.parse(
+  'vimdoc',
+  [[
+  (codeblock
+    (language) @_lang
+    .
+    (code) @code
+    (#any-of? @_lang "lua" "vim")
+    (#set! @code lang @_lang))
+]]
+)
+local run_message_ns = vim.api.nvim_create_namespace('nvim.vimdoc.run_message')
+
+vim.api.nvim_buf_clear_namespace(0, run_message_ns, 0, -1)
+for _, match, metadata in query:iter_matches(tree:root(), 0, 0, -1) do
+  for id, nodes in pairs(match) do
+    local name = query.captures[id]
+    local node = nodes[1]
+    local start, _, end_ = node:parent():range()
+
+    if name == 'code' then
+      vim.api.nvim_buf_set_extmark(0, run_message_ns, start, 0, {
+        virt_text = { { 'Run with `g==`', 'LspCodeLens' } },
+      })
+      local code = vim.treesitter.get_node_text(node, 0)
+      local lang_node = match[metadata[id].lang][1] --[[@as TSNode]]
+      local lang = vim.treesitter.get_node_text(lang_node, 0)
+      for i = start + 1, end_ do
+        code_blocks[i] = { lang = lang, code = code }
+      end
+    end
+  end
+end
+
+vim.keymap.set('n', 'g==', function()
+  local pos = vim.api.nvim_win_get_cursor(0)[1]
+  local code_block = code_blocks[pos]
+  if not code_block then
+    vim.print('No code block found')
+  elseif code_block.lang == 'lua' then
+    vim.cmd.lua(code_block.code)
+  elseif code_block.lang == 'vim' then
+    vim.cmd(code_block.code)
+  end
+end, { buffer = true })
+
+vim.b.undo_ftplugin = (vim.b.undo_ftplugin or '')
+  .. '\n exe "nunmap <buffer> gO" | exe "nunmap <buffer> g=="'
 vim.b.undo_ftplugin = vim.b.undo_ftplugin .. ' | call v:lua.vim.treesitter.stop()'