X-Git-Url: http://git.nguyen.vg/gitweb/?a=blobdiff_plain;f=src%2FnodeSet.ml;h=082802930f44432e6421a75b5bd229027a0c42c8;hb=e1ae19bec9b516d8a531790bba6fb231c17c9862;hp=142476be16f232230f8e0bddf0aecce3baca5f79;hpb=577e04ded43baa0582530316da40777884031dc8;p=SXSI%2Fxpathcomp.git

diff --git a/src/nodeSet.ml b/src/nodeSet.ml
index 142476b..0828029 100644
--- a/src/nodeSet.ml
+++ b/src/nodeSet.ml
@@ -100,11 +100,18 @@ module Mat : S with type t = Tree.node mat =
     let conscat4 e l1 l2 l3 l4 = conscat e l1 (concat l2 (concat l3 l4))
 
     let subtree_tags tree node tag =
-      { clist = SubtreeTags(tree, node, tag);
-	length = Tree.subtree_tags tree node tag }
+      let len = Tree.subtree_tags tree node tag in
+      if len == 0 then empty
+      else
+	{ clist = SubtreeTags(tree, node, tag);
+	  length = len }
+
     let subtree_elements tree node =
-      { clist = SubtreeElts(tree, node);
-	length = Tree.subtree_elements tree node }
+      let len = Tree.subtree_elements tree node in
+      if len == 0 then empty
+      else
+	{ clist = SubtreeElts(tree, node);
+	  length = len }
 
     let fst_tagged tree t tag =
       if Tree.tag tree t == tag then t
@@ -193,8 +200,10 @@ module Mat : S with type t = Tree.node mat =
 	  Unix.close
       in
       ignore (Unix.write fd "<xml_result>\n" 0 13);
-      iter (fun node -> Tree.print_xml v node fd) l;
-      Tree.flush v fd;
+      if l.length > 0 then begin
+	iter (fun node -> Tree.print_xml v node fd) l;
+	Tree.flush v fd;
+      end;
       ignore (Unix.write fd "</xml_result>\n" 0 14);
       finish fd