X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FUnion.java;h=8780d9ea02df515179df4827dc41658897cc3681;hp=a7a76302455b8e9c051224abd3fe022a2a828bb8;hb=6b53048f4413f3c618acc3581d0b4f60a236a9bc;hpb=87f214f3da9f43c3ab93923313845c372f9a96be

diff --git a/src/edu/berkeley/sbp/Union.java b/src/edu/berkeley/sbp/Union.java
index a7a7630..8780d9e 100644
--- a/src/edu/berkeley/sbp/Union.java
+++ b/src/edu/berkeley/sbp/Union.java
@@ -16,17 +16,15 @@ public class Union extends Element implements Iterable<Sequence> {
 
     public Iterator<Sequence> iterator() { return alternatives.iterator(); }
 
-    void reachable(HashSet<Sequence.Position> h) { for(Sequence s : alternatives) s.reachable(h); }
-
     Topology toAtom() {
         if (alternatives.size()==0) throw new RuntimeException("cannot build an Atom from a Union with no productions");
         Topology ret = null;
         for(Sequence s : this) {
             Topology a = s.toAtom();
-            if (a==null) continue;
-            if (ret==null) ret = a.dup();
-            else           ret.add(a.dup());
+            if (ret==null) ret = a;
+            else           ret = ret.union(a);
         }
+        if (ret==null) throw new RuntimeException("confusion on " + this);
         return ret;
     }