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=0ce5f55c34e14380e1be527e6cfaabc00d6b0c4b;hp=3e260f14bbd6500196a197e2afb858bb5bf2d7df;hb=dc9bb3a45ed306e2e35549076842b3e74efecb48;hpb=449c39e0dafd7c736bfcd8d56bbd08b7a99e25a4

diff --git a/src/edu/berkeley/sbp/Sequence.java b/src/edu/berkeley/sbp/Sequence.java
index 3e260f1..0ce5f55 100644
--- a/src/edu/berkeley/sbp/Sequence.java
+++ b/src/edu/berkeley/sbp/Sequence.java
@@ -104,14 +104,7 @@ public abstract class Sequence implements Iterable<Element>, SequenceOrElement {
         this.firstp = new Position(0, null);
     }
 
-    // DO NOT MESS WITH THE FOLLOWING LINE!!!
-    private Forest.Many epsilonForm = null;
-    Forest epsilonForm(Input.Region loc) {
-        if (epsilonForm!=null) return epsilonForm;
-        epsilonForm = new Forest.Many();
-        epsilonForm.merge(firstp().rewrite(loc, false));
-        return epsilonForm;
-    }
+    abstract Forest epsilonForm(Input.Region loc, Cache cache);
 
     protected abstract <T> Forest<T> postReduce(Input.Region loc, Forest<T>[] args, Position p);
 
@@ -124,12 +117,13 @@ public abstract class Sequence implements Iterable<Element>, SequenceOrElement {
         public int ord = -1;
 
         private Forest zero = null;
+        /*
         public Forest zero(Input.Region reg) {
             if (zero != null) return zero;
             if (pos > 0) throw new RuntimeException("Position.zero(): pos>0");
             return zero = rewrite(reg);
         }
-
+        */
                 final int      pos;
         private final Position next;
         private final Position prev;
@@ -160,13 +154,12 @@ public abstract class Sequence implements Iterable<Element>, SequenceOrElement {
 
         // Position /////////////////////////////////////////////////////////////////////////////////
 
-        final <T> Forest<T> rewrite(Input.Region loc) { return rewrite(loc, true); }
-        private final <T> Forest<T> rewrite(Input.Region loc, boolean epsilonCheck) {
-            if (epsilonCheck && this==firstp()) return epsilonForm(loc);
+        final <T> Forest<T> rewrite(Input.Region loc, Cache cache) {
+            if (this==firstp()) epsilonForm(loc, cache);
             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(loc);
-                if (holder[i]==null) throw new Error("bad " + i);
+                if (holder[i]==null) holder[i] = ((Union)elements[i]).epsilonForm(loc, cache);
+                if (holder[i]==null) throw new Error("bad");
             }
             return Sequence.this.postReduce(loc, holder, this);
         }
@@ -226,6 +219,9 @@ public abstract class Sequence implements Iterable<Element>, SequenceOrElement {
         public <T> Forest<T> postReduce(Input.Region loc, Forest<T>[] args, Position p) {
             return (Forest<T>)Forest.create(loc, result, null, false);
         }
+        Forest epsilonForm(Input.Region loc, Cache cache) {
+            return Forest.create(loc, result, null, false);
+        }
     }
 
     static class Singleton extends Sequence {
@@ -234,6 +230,9 @@ public abstract class Sequence implements Iterable<Element>, SequenceOrElement {
         public Singleton(Element[] e, int idx) { super(e); this.idx = idx; }
         public <T> Forest<T> postReduce(Input.Region loc, Forest<T>[] args, Position p) { return args[idx]; }
         Sequence _clone() { return new Singleton(elements,idx); }
+        Forest epsilonForm(Input.Region loc, Cache cache) {
+            return ((Union)elements[idx]).epsilonForm(loc, cache);
+        }
     }
 
     static class Unwrap extends Sequence {
@@ -252,6 +251,9 @@ public abstract class Sequence implements Iterable<Element>, SequenceOrElement {
             for(int i=0; i<args.length; i++) if (!drops[i]) args2[j++] = args[i];
             return Forest.create(loc, (T)tag, args2, true);
         }
+        Forest epsilonForm(Input.Region loc, Cache cache) {
+            return Forest.create(loc, tag, new Forest[0], false);
+        }
     }
 
     static class RewritingSequence extends Sequence {
@@ -282,6 +284,9 @@ public abstract class Sequence implements Iterable<Element>, SequenceOrElement {
             if (spacing) for(int i=0; i<50-len; i++) sb.append(' ');
             return sb;
         }
+        Forest epsilonForm(Input.Region loc, Cache cache) {
+            return Forest.create(loc, tag, new Forest[0], false);
+        }
     }
 
 }