X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FUnion.java;h=1d4841ff718c4aaf272a0bf83902218605458fde;hp=df6c374af8399d98168f3282f5f859580e8eb34b;hb=e4b4b7b0da38d93fc9160b0058a81c1fc7f6773b;hpb=0a0227b9180534d2a431f3d6e08a398bde2244c4

diff --git a/src/edu/berkeley/sbp/Union.java b/src/edu/berkeley/sbp/Union.java
index df6c374..1d4841f 100644
--- a/src/edu/berkeley/sbp/Union.java
+++ b/src/edu/berkeley/sbp/Union.java
@@ -36,6 +36,9 @@ public class Union extends Element implements Iterable<Sequence> {
         this.synthetic = synthetic;
     }
 
+    public static Union epsilon = new Union("()");
+    static { epsilon.add(Sequence.empty); }
+
     private Forest.Ref epsilonForm = null;
     Forest epsilonForm() {
         if (epsilonForm != null) return epsilonForm;
@@ -50,7 +53,7 @@ public class Union extends Element implements Iterable<Sequence> {
 
     public String toString() { return shortForm; }
     private static String pad(int i,String s) { return s.length() >= i ? s : pad(i-1,s)+" "; }
-    void toString(StringBuffer sb) {
+    public void toString(StringBuffer sb) {
         if (synthetic) return;
         boolean first = true;
         if (alternatives.size()==0) {