src/Pure/Isar/attrib.ML

     val thy = Context.theory_of context;
     val (space, tab) = Attributes.get thy;
     fun attr src =
       let val ((name, _), pos) = Args.dest_src src in
         (case Symtab.lookup tab name of
-          NONE => error ("Unknown attribute: " ^ quote name ^ Position.str_of pos)
+          NONE => error ("Unknown attribute: " ^ quote name ^ Position.here pos)
         | SOME (att, _) =>
             (Context_Position.report_generic context pos (Name_Space.markup space name); att src))
       end;
   in attr end;
 

     val src2 = Args.closure src1;
   in (src2, result) end;
 
 fun err msg src =
   let val ((name, _), pos) = Args.dest_src src
-  in error (msg ^ " " ^ quote name ^ Position.str_of pos) end;
+  in error (msg ^ " " ^ quote name ^ Position.here pos) end;
 
 fun eval src ((th, dyn), (decls, context)) =
   (case (apply_att src (context, th), dyn) of
     ((_, (NONE, SOME th')), NONE) => ((th', NONE), (decls, context))
   | ((_, (NONE, SOME _)), SOME _) => err "Mixed dynamic attribute followed by static rule" src