1 files changed, 27 insertions, 8 deletions
diff --git a/scripts/gen_help_html.lua b/scripts/gen_help_html.lua
index 13601b91f5..c647484905 100644
--- a/scripts/gen_help_html.lua
+++ b/scripts/gen_help_html.lua
@@ -249,6 +249,16 @@ local function getbuflinestr(node, bufnr, offset)
   return table.concat(lines, '\n')
 end
 
+-- Gets the whitespace just before `node` from the raw buffer text.
+-- Needed for preformatted `old` lines.
+local function getws(node, bufnr)
+  local line1, c1, line2, _ = node:range()
+  local raw = vim.fn.getbufline(bufnr, line1 + 1, line2 + 1)[1]
+  local text_before = raw:sub(1, c1)
+  local leading_ws = text_before:match('%s+$') or ''
+  return leading_ws
+end
+
 local function get_tagname(node, bufnr)
   local text = vim.treesitter.get_node_text(node, bufnr)
   local tag = (node:type() == 'optionlink' or node:parent():type() == 'optionlink') and ("'%s'"):format(text) or text
@@ -354,12 +364,21 @@ local function visit_node(root, level, lang_tree, headings, opt, stats)
   local parent = root:parent() and root:parent():type() or nil
   local text = ''
   local trimmed
-  local function node_text(node)
-    return vim.treesitter.get_node_text(node or root, opt.buf)
+  -- Gets leading whitespace of `node`.
+  local function ws(node)
+    node = node or root
+    local ws_ = getws(node, opt.buf)
+    -- XXX: first node of a (line) includes whitespace, even after
+    -- https://github.com/neovim/tree-sitter-vimdoc/pull/31 ?
+    if ws_ == '' then
+      ws_ = vim.treesitter.get_node_text(node, opt.buf):match('^%s+') or ''
+    end
+    return ws_
   end
-  -- Gets leading whitespace of the current node.
-  local function ws()
-    return node_text():match('^%s+') or ''
+  local function node_text(node, ws_)
+    node = node or root
+    ws_ = (ws_ == nil or ws_ == true) and getws(node, opt.buf) or ''
+    return string.format('%s%s', ws_, vim.treesitter.get_node_text(node, opt.buf))
   end
 
   if root:named_child_count() == 0 or node_name == 'ERROR' then
@@ -401,7 +420,7 @@ local function visit_node(root, level, lang_tree, headings, opt, stats)
     if root:has_error() then
       return text
     end
-    return ('<div class="help-column_heading">%s%s</div>'):format(ws(), trimmed)
+    return ('<div class="help-column_heading">%s</div>'):format(text)
   elseif node_name == 'block' then
     if is_blank(text) then
       return ''
@@ -462,9 +481,9 @@ local function visit_node(root, level, lang_tree, headings, opt, stats)
     end
     local in_heading = vim.tbl_contains({'h1', 'h2', 'h3'}, parent)
     local cssclass = (not in_heading and get_indent(node_text()) > 8) and 'help-tag-right' or 'help-tag'
-    local tagname = node_text(root:child(1))
+    local tagname = node_text(root:child(1), false)
     if vim.tbl_count(stats.first_tags) < 2 then
-      -- First 2 tags in the doc will be anchored at the main heading.
+      -- Force the first 2 tags in the doc to be anchored at the main heading.
       table.insert(stats.first_tags, tagname)
       return ''
     end