src/Pure/General/xml.scala

 
 
   /* string representation */
 
   private def append_text(text: String, s: StringBuilder) {
-    if (text == null) s ++ text
+    if (text == null) s ++= text
     else {
       for (c <- text.iterator) c match {
-        case '<' => s ++ "&lt;"
-        case '>' => s ++ "&gt;"
-        case '&' => s ++ "&amp;"
-        case '"' => s ++ "&quot;"
-        case '\'' => s ++ "&apos;"
-        case _ => s + c
+        case '<' => s ++= "&lt;"
+        case '>' => s ++= "&gt;"
+        case '&' => s ++= "&amp;"
+        case '"' => s ++= "&quot;"
+        case '\'' => s ++= "&apos;"
+        case _ => s += c
       }
     }
   }
 
   private def append_elem(name: String, atts: Attributes, s: StringBuilder) {
-    s ++ name
+    s ++= name
     for ((a, x) <- atts) {
-      s ++ " "; s ++ a; s ++ "=\""; append_text(x, s); s ++ "\""
+      s ++= " "; s ++= a; s ++= "=\""; append_text(x, s); s ++= "\""
     }
   }
 
   private def append_tree(tree: Tree, s: StringBuilder) {
     tree match {
       case Elem(name, atts, Nil) =>
-        s ++ "<"; append_elem(name, atts, s); s ++ "/>"
+        s ++= "<"; append_elem(name, atts, s); s ++= "/>"
       case Elem(name, atts, ts) =>
-        s ++ "<"; append_elem(name, atts, s); s ++ ">"
+        s ++= "<"; append_elem(name, atts, s); s ++= ">"
         for (t <- ts) append_tree(t, s)
-        s ++ "</"; s ++ name; s ++ ">"
+        s ++= "</"; s ++= name; s ++= ">"
       case Text(text) => append_text(text, s)
     }
   }