diff --git a/margin-notes/margin-notes.lua b/margin-notes/margin-notes.lua
index 5881fdb..253612c 100644
--- a/margin-notes/margin-notes.lua
+++ b/margin-notes/margin-notes.lua
@@ -87,13 +87,13 @@ end
 
 local config = {}
 
-function add_rendering(config, class,
+local function add_rendering(cfg, class,
                               body_text, note_text,
                               docx_body_text, docx_note_text,
                               odt_body_text, odt_note_text,
                               csname, position)
   -- The values are plain strings (not the empty string!) or nil.
-  config[class] = {
+  cfg[class] = {
     body_text = body_text,
     note_text = note_text,
     docx_body_text = docx_body_text,
@@ -117,19 +117,19 @@ local function get_renderings_config(meta)
   for key, value in pairs(meta) do
     if key == 'mrgnn-define-renderings' then
       for i = 1, #value do
-        this_value = value[i]
+        local definition = value[i]
         add_rendering(config,
-          meta_to_str(this_value.class),
-          meta_to_str(this_value['body-text']),
-          meta_to_str(this_value['note-text']),
-          meta_to_str(this_value['docx-body-text']),
-          meta_to_str(this_value['docx-note-text']),
-          meta_to_str(this_value['odt-body-text']
-                      or this_value['body-text']),
-          meta_to_str(this_value['odt-note-text']
-                      or this_value['note-text']),
-          meta_to_str(this_value['csname']),
-          meta_to_str(this_value['position']) or POS_DEFAULT
+          meta_to_str(definition.class),
+          meta_to_str(definition['body-text']),
+          meta_to_str(definition['note-text']),
+          meta_to_str(definition['docx-body-text']),
+          meta_to_str(definition['docx-note-text']),
+          meta_to_str(definition['odt-body-text']
+                      or definition['body-text']),
+          meta_to_str(definition['odt-note-text']
+                      or definition['note-text']),
+          meta_to_str(definition['csname']),
+          meta_to_str(definition['position']) or POS_DEFAULT
         )
       end
     end
@@ -256,6 +256,7 @@ local function get_replacement(placeholder,
     a plain string otherwise.
     Markdown is interpreted in the first case only.
   ]]--
+  local replacement
   if placeholder == 'content' then
     if replacement_is_list then
       replacement = instance_content
@@ -266,7 +267,7 @@ local function get_replacement(placeholder,
     local key = get_substring(placeholder, #'attr.' + 1)
     if replacement_is_list then
       local replacement_markdown = instance_attr[key]
-        or '**' .. UNDEFINED .. '**'
+        or ('**' .. UNDEFINED .. '**')
       replacement = to_pandoc_inlines(replacement_markdown)
     else
       replacement = instance_attr[key] or UNDEFINED
@@ -457,17 +458,17 @@ local function template_to_function(template)
   end
 end
 
-local function define_rendering_functions(meta)
+local function define_rendering_functions()
   local format_prefix = ''
   if FORMAT == 'opendocument' then
     format_prefix = 'odt_'
   elseif FORMAT == 'openxml' then
     format_prefix = 'docx_'
   end
-  for class_name, class_config in pairs(config) do
-    config[class_name].render = {}
+  for _, class_config in pairs(config) do
+    class_config.render = {}
     for _, part in ipairs({'body', 'note'}) do
-      config[class_name].render[part] =
+      class_config.render[part] =
         template_to_function(class_config[format_prefix .. part .. '_text'])
     end
   end
@@ -484,7 +485,7 @@ end
 
 local function Meta(meta)
   get_renderings_config(meta)
-  define_rendering_functions(meta)
+  define_rendering_functions()
   set_macro_definition(meta)
   return meta
 end
@@ -544,9 +545,9 @@ end
 local function render_margin_notes(span)
   for class_name, class_config in pairs(config) do
     if span.classes:includes(class_name) then
-      local render_note = config[class_name].render.note
-      local render_body = config[class_name].render.body
-      local note_position = config[class_name].position
+      local render_note = class_config.render.note
+      local render_body = class_config.render.body
+      local note_position = class_config.position
       local note_id = span.identifier
       local margin_note = {}
       local body = {}
@@ -561,7 +562,7 @@ local function render_margin_notes(span)
       local span_with_note = {}
       if note_position == 'before' then
         span_with_note = margin_note
-        insert_in_table(span_with_note, span)        
+        insert_in_table(span_with_note, span)
       elseif note_position == 'after' then
         span_with_note = { span, unpack_table(margin_note) }
       else