1.1 --- a/src/Pure/General/yxml.ML	Fri Aug 15 15:50:49 2008 +0200
     1.2 +++ b/src/Pure/General/yxml.ML	Fri Aug 15 15:50:50 2008 +0200
     1.3 @@ -42,8 +42,9 @@
     1.4  
     1.5  (* output *)
     1.6  
     1.7 -fun output_markup (name, atts) =
     1.8 -  (XY ^ name ^ implode (map (fn (a, x) => Y ^ a ^ "=" ^ x) atts) ^ X, XYX);
     1.9 +fun output_markup (markup as (name, atts)) =
    1.10 +  if Markup.is_none markup then ("", "")
    1.11 +  else (XY ^ name ^ implode (map (fn (a, x) => Y ^ a ^ "=" ^ x) atts) ^ X, XYX);
    1.12  
    1.13  fun element name atts body =
    1.14    let val (pre, post) = output_markup (name, atts)