--- a/pvl/dns/process.py	Tue Mar 03 12:14:22 2015 +0200
+++ b/pvl/dns/process.py	Tue Mar 03 12:42:26 2015 +0200
@@ -68,9 +68,13 @@
         file.write(unicode(item))
         file.write('\n')
 
-def apply_zone (options, args):
+def apply_zone (options, args,
+        include_trace=None,
+):
     """
         ZoneLine.load() in given zones.
+            
+            include_trace           - append included paths to given list
 
         Yields ZoneDirective/ZoneRecord items.
     """
@@ -78,6 +82,9 @@
     for file in pvl.args.apply_files(args, 'r', options.input_charset) :
         log.info("%s: reading zone", file.name)
 
+        if include_trace is not None:
+            include_trace.append(file.name)
+
         for item in zone.ZoneLine.load(file):
             yield item