lazy Isabelle_System.default supports implicit boot;

--- a/src/Pure/System/gui_setup.scala	Wed Jun 22 21:27:20 2011 +0200
+++ b/src/Pure/System/gui_setup.scala	Wed Jun 22 21:35:48 2011 +0200
@@ -42,7 +42,7 @@
     text.append("JVM name: " + Platform.jvm_name + "\n")
     text.append("JVM platform: " + Platform.jvm_platform + "\n")
     try {
-      val isabelle_system = new Isabelle_System
+      val isabelle_system = Isabelle_System.default
       text.append("ML platform: " + isabelle_system.getenv("ML_PLATFORM") + "\n")
       text.append("Isabelle platform: " + isabelle_system.getenv("ISABELLE_PLATFORM") + "\n")
       val platform64 = isabelle_system.getenv("ISABELLE_PLATFORM64")

--- a/src/Pure/System/isabelle_process.scala	Wed Jun 22 21:27:20 2011 +0200
+++ b/src/Pure/System/isabelle_process.scala	Wed Jun 22 21:35:48 2011 +0200
@@ -69,7 +69,7 @@
   /* demo constructor */
 
   def this(args: String*) =
-    this(new Isabelle_System, Time.seconds(10),
+    this(Isabelle_System.default, Time.seconds(10),
       actor { loop { react { case res => Console.println(res) } } }, args: _*)
 
 

--- a/src/Pure/System/isabelle_system.scala	Wed Jun 22 21:27:20 2011 +0200
+++ b/src/Pure/System/isabelle_system.scala	Wed Jun 22 21:35:48 2011 +0200
@@ -18,6 +18,11 @@
 import scala.collection.mutable
 
 
+object Isabelle_System
+{
+  lazy val default: Isabelle_System = new Isabelle_System
+}
+
 class Isabelle_System(this_isabelle_home: String) extends Standard_System
 {
   def this() = this(null)