it all works

[sbp.git] / src / edu / berkeley / sbp / Sequence.java

diff --git a/src/edu/berkeley/sbp/Sequence.java b/src/edu/berkeley/sbp/Sequence.java
index ee3fd4b..83d9b6f 100644 (file)
--- a/src/edu/berkeley/sbp/Sequence.java
+++ b/src/edu/berkeley/sbp/Sequence.java
@@ -114,7 +114,11 @@ public abstract class Sequence extends Element implements Iterable<Element> {
         final <T> Forest<T> rewrite(Token.Location loc) {
             if (this==firstp() && eps) return epsilonForm;
             eps = true;
-            for(int i=pos; i<elements.length; i++) if (holder[i]==null) holder[i] = elements[i].epsilonForm();
+            for(int i=0; i<pos; i++) if (holder[i]==null) throw new Error("realbad " + i);
+            for(int i=pos; i<elements.length; i++) {
+                if (holder[i]==null) holder[i] = elements[i].epsilonForm();
+                if (holder[i]==null) throw new Error("bad " + i);
+            }
             Forest<T> ret = Sequence.this.postReduce(loc, holder);
             for(int k=0; k<pos; k++) holder[k] = null; // to help GC
             if (this==firstp()) { if (epsilonForm==null) epsilonForm=new Forest.Ref(); epsilonForm.merge(ret); return epsilonForm; }
@@ -178,6 +182,7 @@ public abstract class Sequence extends Element implements Iterable<Element> {
         public Unwrap(Element[] e, HashSet<Sequence> and, HashSet<Sequence> not)                  { super(e, and, not); this.drops = null; }
         public Unwrap(Element[] e, boolean[] drops, HashSet<Sequence> and, HashSet<Sequence> not) { super(e, and, not); this.drops = drops; }
         public <T> Forest<T> postReduce(Token.Location loc, Forest<T>[] args) {
+            for(int i=0; i<args.length; i++) if (args[i]==null) throw new Error();
             if (drops==null) return Forest.create(loc, null, args, this, true, false);
             int count = 0;
             for(int i=0; i<drops.length; i++) if (!drops[i]) count++;