diff -r c14c9a41f1ac -r d4058295affb src/Pure/General/symbol.scala
--- a/src/Pure/General/symbol.scala	Sat Dec 27 11:54:08 2008 +0100
+++ b/src/Pure/General/symbol.scala	Sat Dec 27 14:57:30 2008 +0100
@@ -78,7 +78,7 @@
 
   /** Symbol interpretation **/
 
-  class Interpretation {
+  class Interpretation(isabelle_system: IsabelleSystem) {
 
     private var symbols = new HashMap[String, HashMap[String, String]]
     private var decoder: Recoder = null
@@ -125,7 +125,7 @@
     }
 
     private def read_symbols(path: String) = {
-      val file = new File(IsabelleSystem.platform_path(path))
+      val file = new File(isabelle_system.platform_path(path))
       if (file.canRead) {
         for (line <- Source.fromFile(file).getLines) read_line(line)
       }