X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FSequence.java;fp=src%2Fedu%2Fberkeley%2Fsbp%2FSequence.java;h=d3d8d8a136d124dfdca130cd15ad651e9f146aa0;hp=95353572a770f88b3952a65f43ba63cbbf2e6432;hb=e84029a8b861075d6d0ed5040f919b2e4da4c98f;hpb=a8478f5ddfbfbc8d910d09f27163cbd55752d3b6

diff --git a/src/edu/berkeley/sbp/Sequence.java b/src/edu/berkeley/sbp/Sequence.java
index 9535357..d3d8d8a 100644
--- a/src/edu/berkeley/sbp/Sequence.java
+++ b/src/edu/berkeley/sbp/Sequence.java
@@ -14,6 +14,8 @@ public abstract class Sequence implements Iterable<Element>, SequenceOrElement {
 
     protected final Element[] elements;
 
+    public boolean needed_or_hated = false;
+
     final HashSet<Sequence> hated  = new HashSet<Sequence>();
 
     final HashSet<Sequence> needs  = new HashSet<Sequence>();
@@ -65,14 +67,20 @@ public abstract class Sequence implements Iterable<Element>, SequenceOrElement {
     ////////////////////////////////////////////////////////////////////////////////
 
     /** return a new sequence identical to this one, but with a positive conjunct <tt>s</tt> */
-    public Sequence and(Sequence s) { Sequence ret = dup(); ret.needs.add(s); return ret; }
+    public Sequence and(Sequence s) { Sequence ret = dup(); ret.needs.add(s); s.needed_or_hated=true; return ret; }
 
     /** return a new sequence identical to this one, but with a negative conjunct <tt>s</tt> */
-    public Sequence andnot(Sequence s) { Sequence ret = dup(); ret.hates.add(s); s.hated.add(ret); return ret; }
+    public Sequence andnot(Sequence s) { Sequence ret = dup(); ret.hates.add(s); s.hated.add(ret); s.needed_or_hated=true; return ret; }
 
     /** return a new sequence identical to this one, but with a follow-set restricted to <tt>a</tt> */
     public Sequence followedBy(Atom a) { Sequence ret = dup(); ret.follow = a; return ret; }
 
+    boolean hatesAny(Iterable<Sequence> it) {
+        if (hates.isEmpty()) return false;
+        for(Sequence s : it) if (hates.contains(s)) return true;
+        return false;
+    }
+
     Iterable<Sequence> needs() { return needs; }
     Iterable<Sequence> hates() { return hates; }