X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;ds=sidebyside;f=src%2Fedu%2Fberkeley%2Fsbp%2FUnion.java;h=4de0bb4969c58512982b7977fda60c9c6eaeac05;hb=1a249057cbfd2180910e46672eafee3af46ae470;hp=db0db7dca1a322625895ee88f6d338a7934623ba;hpb=0516ea34996c86664928ef948013b749876b87ec;p=sbp.git

diff --git a/src/edu/berkeley/sbp/Union.java b/src/edu/berkeley/sbp/Union.java
index db0db7d..4de0bb4 100644
--- a/src/edu/berkeley/sbp/Union.java
+++ b/src/edu/berkeley/sbp/Union.java
@@ -10,28 +10,24 @@ import java.lang.ref.*;
 /** an element which can produce one of several alternatives */
 public class Union extends Element implements Iterable<Sequence> {
 
+    /** display form for the Union (ie not including the RHS) */
     final String shortForm;
+
+    /** this is just a hint to use when printing out the grammar in visual form */
     final boolean synthetic;
+
+    /** the actual alternatives */
     private final List<Sequence> alternatives = new ArrayList<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 (ret==null) ret = a.dup();
-            else           ret = ret.union(a.dup());
-        }
-        if (ret==null) throw new RuntimeException("confusion on " + this);
-        return ret;
-    }
+    public boolean contains(Sequence s) { return alternatives.contains(s); }
 
     /** adds an alternative */
-    public void add(Sequence s) { alternatives.add(s); }
+    public void add(Sequence s) {
+        alternatives.add(s);
+        for(Sequence n : s.needs) add(n);
+        for(Sequence n : s.hates) add(n);
+    }
 
     /**
      *  Since every cycle in a non-degenerate grammar contains at