src/Tools/jEdit/src/jedit/Plugin.scala

   }
 
   // Isabelle system instance
   var system: IsabelleSystem = null
   def symbols = system.symbols
+
+  // settings
+  def default_logic = {
+    val logic = Isabelle.Property("logic")
+    if (logic != null) logic else Isabelle.system.getenv_strict("ISABELLE_LOGIC")
+  }
 
   // plugin instance
   var plugin: Plugin = null
 
   // running provers