--- a/inst/@dataframe/private/df_mapper.m
+++ b/inst/@dataframe/private/df_mapper.m
@@ -28,7 +28,7 @@
 
   resu = df_allmeta(df);
   resu._data = cellfun(@(x) feval(func, x, varargin{:}), df._data, ...
-		       "UniformOutput", false);
+                       "UniformOutput", false);
   resu._rep = df._rep; %# things didn't change
   resu._type = cellfun(@(x) class(x(1)), resu._data, "UniformOutput", false);