From: Stefano Zacchiroli <zack@upsilon.cc>
Date: Thu, 20 Jul 2006 15:02:52 +0000 (+0000)
Subject: avoid collapsing node that does not need to be, i.e.:
X-Git-Tag: 0.4.95@7852~1168
X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=commitdiff_plain;h=55ae9c989557fbb879104962b0db50b19a9cfd2b;p=helm.git

avoid collapsing node that does not need to be, i.e.:
- nodes with no outgoing edges
- nodes which have not been expanded before
---

diff --git a/components/metadata/metadataDeps.ml b/components/metadata/metadataDeps.ml
index 0e1dbb817..3247114a2 100644
--- a/components/metadata/metadataDeps.ml
+++ b/components/metadata/metadataDeps.ml
@@ -205,9 +205,16 @@ struct
       [], 0
 
   let collapse uri (adjlist, _root, f, _invert) =
+    try
+      let neighbs = UriTbl.find adjlist uri in
+      if Lazy.lazy_is_val neighbs.adjacency then
+        (* do not collapse already collapsed nodes *)
+        if Lazy.force neighbs.adjacency <> [] then
+          (* do not collapse nodes with no outgoing edges *)
+          UriTbl.replace adjlist uri { adjacency = lazy (f uri); shown = 0 }
+    with Not_found ->
       (* do not add a collapsed node if it was not part of the graph *)
-    if UriTbl.mem adjlist uri then
-      UriTbl.replace adjlist uri { adjacency = lazy (f uri); shown = 0 }
+      ()
 
   let graph_of_fun ?(invert = false) f ~dbd uri =
     let f ~dbd uri =