anchor.diff:  props_filter([{slug, ""}|T], Acc, Context) ->
       props_filter(T, [{slug, []} | Acc], Context);
   props_filter([{slug, Slug}|T], Acc, Context) ->
  -    props_filter(T, [{slug, z_string:to_slug(Slug)} | Acc], Context);
  +    props_filter(T, [{slug, to_slug(Slug, Context)} | Acc], Context);
   props_filter([{custom_slug, P}|T], Acc, Context) ->
       props_filter(T, [{custom_slug, z_convert:to_bool(P)} | Acc], Context);
   props_filter([{is_published, P}|T], Acc, Context) ->
  
positive.code:                         undefined ->
                              Props;
                          Title ->
                              lists:keystore(slug, 1, Props, {slug, z_string:to_slug(Title)})
                      end;
                  _ ->
                      Props
  
negative.code: 
  %% @doc Fill in some defaults for empty props on insert.
  %% @spec props_defaults(Props1, Context) -> Props2
  props_defaults(Props, Context) ->
      % Generate slug from the title (when there is a title)
      Props1 = case proplists:get_value(slug, Props) of
                  undefined ->
  