tuned;

--- a/src/Pure/General/path.scala	Tue Jul 05 09:54:39 2011 +0200
+++ b/src/Pure/General/path.scala	Tue Jul 05 10:54:05 2011 +0200
@@ -138,11 +138,12 @@
 
   /* expand */
 
-  def expand(env: String => String): Path =
+  def expand: Path =
   {
     def eval(elem: Path.Elem): List[Path.Elem] =
       elem match {
-        case Path.Variable(s) => Path.explode(env(s)).elems
+        case Path.Variable(s) =>
+          Path.explode(Isabelle_System.getenv_strict(s)).elems
         case x => List(x)
       }
 

--- a/src/Pure/System/isabelle_system.scala	Tue Jul 05 09:54:39 2011 +0200
+++ b/src/Pure/System/isabelle_system.scala	Tue Jul 05 10:54:05 2011 +0200
@@ -120,7 +120,7 @@
 
   /* path specifications */
 
-  def standard_path(path: Path): String = path.expand(getenv_strict).implode
+  def standard_path(path: Path): String = path.expand.implode
 
   def platform_path(path: Path): String = standard_system.jvm_path(standard_path(path))
   def platform_file(path: Path) = new File(platform_path(path))

--- a/src/Pure/System/standard_system.scala	Tue Jul 05 09:54:39 2011 +0200
+++ b/src/Pure/System/standard_system.scala	Tue Jul 05 10:54:05 2011 +0200
@@ -264,8 +264,9 @@
 
 class Standard_System
 {
+  /* platform_root */
+
   val platform_root = if (Platform.is_windows) Cygwin.check_root() else "/"
-  override def toString = platform_root
 
 
   /* jvm_path */