X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FSequence.java;h=adf93fa64d35b8c645d7e3c72928f8585fdf2e03;hp=fcff530b8db6eaff5009d3943797c80d29d031d2;hb=c366dacc334fe2e35835164f5a37d3eebb2ca6d5;hpb=0a0227b9180534d2a431f3d6e08a398bde2244c4

diff --git a/src/edu/berkeley/sbp/Sequence.java b/src/edu/berkeley/sbp/Sequence.java
index fcff530..adf93fa 100644
--- a/src/edu/berkeley/sbp/Sequence.java
+++ b/src/edu/berkeley/sbp/Sequence.java
@@ -35,11 +35,23 @@ public abstract class Sequence extends Element implements Iterable<Element> {
 
     ////////////////////////////////////////////////////////////////////////////////
 
+    public Element noFollow = null;
+    public String name = null;
+    public void setName(String name) { this.name = name; }
+    public final Topology noFollow() { return noFollow==null ? null : noFollow.toAtom(); }
+
+    Topology toAtom() {
+        if (elements.length!=1) throw new RuntimeException("cannot invoke toAtom() on a Sequence with " + elements.length + " elements: " + this);
+        return elements[0].toAtom();
+    }
+
     protected final Element[] elements;
 
+          HashSet<Sequence> needed;
+          HashSet<Sequence> hated;
     final HashSet<Sequence> needs;
     final HashSet<Sequence> hates;
-          boolean           lame  = false;
+    public boolean           lame  = false;
 
     final Position          firstp;
     Position firstp() { return firstp; }
@@ -48,15 +60,26 @@ public abstract class Sequence extends Element implements Iterable<Element> {
     protected Sequence(Element[] elements, HashSet<Sequence> and, HashSet<Sequence> not) {
         this.needs = and==null ? new HashSet<Sequence>() : and;
         this.hates = not==null ? new HashSet<Sequence>() : not;
-        //for(Sequence s : needs) s.lame = true;
-        //for(Sequence s : hates) s.lame = true;
+        if (this.needs != null)
+            for(Sequence s : this.needs)
+                (s.needed==null?(s.needed=new HashSet<Sequence>()):s.needed).add(this);
+        if (this.hates != null)
+            for(Sequence s : this.hates)
+                (s.hated==null?(s.hated=new HashSet<Sequence>()):s.hated).add(this);
         this.elements = elements;
         this.firstp = new Position(0);
     }
 
-    void reachable(HashSet<Position> h) { firstp().reachable(h); }
-
-    Forest epsilonForm() { return firstp().rewrite(null); }
+    // DO NOT MESS WITH THE FOLLOWING LINE!!!
+    private Forest.Ref epsilonForm = null;
+    private boolean eps = false;
+    Forest epsilonForm() {
+        if (epsilonForm==null) {
+            epsilonForm = new Forest.Ref();
+            epsilonForm.merge(firstp().rewrite2(null));
+        }
+        return epsilonForm;
+    }
 
     protected abstract <T> Forest<T> postReduce(Token.Location loc, Forest<T>[] args);
 
@@ -66,12 +89,6 @@ public abstract class Sequence extends Element implements Iterable<Element> {
     /** the imaginary position before or after an element of a sequence; corresponds to an "LR item" */
     public class Position {
 
-        void reachable(HashSet<Position> h) {
-            if (h.contains(this)) return;
-            h.add(this);
-            if (element() != null) element().reachable(h);
-        }
-
                 final int      pos;
         private final Position next;
                 final Forest[] holder;
@@ -103,8 +120,17 @@ public abstract class Sequence extends Element implements Iterable<Element> {
 
         // Reduction /////////////////////////////////////////////////////////////////////////////////
 
-        <T> Forest<T> rewrite(Token.Location loc) {
-            for(int i=pos; i<elements.length; i++) if (holder[i]==null) holder[i] = elements[i].epsilonForm();
+        final <T> Forest<T> rewrite(Token.Location loc) {
+            if (this==firstp()) return epsilonForm();
+            return rewrite2(loc);
+        }
+
+        final <T> Forest<T> rewrite2(Token.Location loc) {
+            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
             return ret;
@@ -144,7 +170,7 @@ public abstract class Sequence extends Element implements Iterable<Element> {
         private final Object result;
         public Constant(Element[] e, Object result, HashSet<Sequence> and, HashSet<Sequence> not) { super(e, and, not); this.result = result; }
         public <T> Forest<T> postReduce(Token.Location loc, Forest<T>[] args) {
-            return (Forest<T>)Forest.leaf(loc, result, this);
+            return (Forest<T>)Forest.leaf(loc, result);
         }
         static class Drop extends Constant {
             public Drop(Element[] e, HashSet<Sequence> and, HashSet<Sequence> not, boolean lame) {
@@ -159,26 +185,27 @@ public abstract class Sequence extends Element implements Iterable<Element> {
         private final int idx;
         public Singleton(Element e, HashSet<Sequence> and, HashSet<Sequence> not) { this(new Element[] { e }, 0, and, not); }
         public Singleton(Element[] e, int idx, HashSet<Sequence> and, HashSet<Sequence> not) { super(e, and, not); this.idx = idx; }
-        public <T> Forest<T> postReduce(Token.Location loc, Forest<T>[] args) { return (Forest<T>)Forest.singleton(loc, args[idx], this); }
+        public <T> Forest<T> postReduce(Token.Location loc, Forest<T>[] args) { return (Forest<T>)Forest.singleton(loc, args[idx]); }
     }
 
-    static class Unwrap extends Sequence {
+    public static class Unwrap extends Sequence {
         private boolean[] drops;
         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) {
-            if (drops==null) return Forest.create(loc, null, args, this, true, false);
+            for(int i=0; i<args.length; i++) if (args[i]==null) throw new Error();
+            if (drops==null) return Forest.create(loc, null, args, true, false);
             int count = 0;
             for(int i=0; i<drops.length; i++) if (!drops[i]) count++;
             Forest<T>[] args2 = new Forest[count];
             int j = 0;
             for(int i=0; i<args.length; i++) if (!drops[i]) args2[j++] = args[i];
-            return Forest.create(loc, null, args2, this, true, false);            
+            return Forest.create(loc, null, args2, true, false);            
         }
     }
 
     static class RewritingSequence extends Sequence {
-        private final Object tag;
+        /*private*/public final Object tag;
         private final boolean[] drops;
         private int count = 0;
         public RewritingSequence(Object tag, Element[] e, HashSet<Sequence> and, HashSet<Sequence> not) { this(tag, e, null, and, not); }
@@ -192,7 +219,8 @@ public abstract class Sequence extends Element implements Iterable<Element> {
             Forest<T>[] args2 = new Forest[count];
             int j = 0;
             for(int i=0; i<args.length; i++) if (!drops[i]) args2[j++] = args[i];
-            return Forest.create(loc, (T)tag, args2, this, false, false);
+            //System.out.println("reduce \""+tag+"\"");
+            return Forest.create(loc, (T)tag, args2, false, false);
         }
         public StringBuffer toString(StringBuffer sb, boolean spacing) {
             int len = sb.length();