#ifndef __SG_CONDITION_HXX
#define __SG_CONDITION_HXX
-#include <simgear/debug/logstream.hxx>
-#include <simgear/props/props.hxx>
-#include <simgear/props/props_io.hxx>
#include <simgear/structure/SGReferenced.hxx>
-\f
+#include <simgear/structure/SGSharedPtr.hxx>
+
+class SGPropertyNode;
+
////////////////////////////////////////////////////////////////////////
// Conditions.
////////////////////////////////////////////////////////////////////////