intermediate checkpoint

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

diff --git a/src/edu/berkeley/sbp/Forest.java b/src/edu/berkeley/sbp/Forest.java
index 5c09170..e675f63 100644 (file)
--- a/src/edu/berkeley/sbp/Forest.java
+++ b/src/edu/berkeley/sbp/Forest.java
@@ -18,8 +18,7 @@ public abstract class Forest<T> {
 
     /** expand this forest into a set of trees */
     public abstract HashSet<Tree<T>>  expand(boolean toss);
-
-    abstract boolean valid();
+    public abstract boolean empty();
 
     static <T> Forest<T>   singleton(Token.Location loc, Sequence creator)                       { return create(loc, null, new Forest[] { }, creator, false, true); }
     static <T> Forest<T>   singleton(Token.Location loc, Forest<T> body, Sequence creator)       { return create(loc, null, new Forest[] { body }, creator, false, true); }
@@ -63,16 +62,15 @@ public abstract class Forest<T> {
                         b.expand(toss, toks, 0, h);
 
             } else {
-                if (tokens[i]!=null) {
-                    HashSet<Tree<T>> exp = tokens[i].expand(toss);
-                    if (exp != null)
-                        for(Tree<T> r : exp) {
-                            int old = toks.size();
-                            toks.add(r);
-                            expand(toss, toks, i+1, h);
-                            while(toks.size() > old) toks.remove(toks.size()-1);
-                        }
+                boolean hit = false;
+                for(Tree<T> r : tokens[i].expand(toss)) {
+                    hit = true;
+                    int old = toks.size();
+                    toks.add(r);
+                    expand(toss, toks, i+1, h);
+                    while(toks.size() > old) toks.remove(toks.size()-1);
                 }
+                //if (!hit) throw new Error();
             }
             return h;
         }
@@ -85,24 +83,6 @@ public abstract class Forest<T> {
             else for(Body b : (IterableForest<T>)tokens[0]) b.addTo(h);
         }
 
-        private boolean kcache = false;
-        private boolean keep = false;
-        public boolean keep() {
-            if (kcache) return keep;
-            kcache = true;
-            for(Forest<T> token : tokens) if (!token.valid()) return keep = false;
-            return keep = creator==null || (creator.needs.size()==0 && creator.hates.size()==0);
-        }
-        public boolean keep(Iterable<Body<T>> h) {
-            if (keep()) return true;
-            for(Forest<T> token : tokens) if (!token.valid()) return false;
-            int needs = 0;
-            for(Body<T> b : h) {
-                if (creator.hates.contains(b.creator) && b.keep(h)) return false;
-                if (creator.needs.contains(b.creator) && b.keep(h)) needs--;
-            }
-            return needs <= -1 * creator.needs.size();
-        }
 
         private boolean rep = false;
         public String toString() {
@@ -140,47 +120,30 @@ public abstract class Forest<T> {
      *  viewed, it becomes immutable
      */
     static class Ref<T> extends IterableForest<T> {
+        public boolean empty() {
+            if (res!=null) return res.empty();
+            for(Forest f : hp) if (!f.empty()) return false;
+            return true;
+        }
         private FastSet<Forest> hp = new FastSet<Forest>();
         private Forest res = null;
-        public boolean valid = false;
         public Ref() { }
         public void merge(Forest p) {
-            //if (p==null) throw new Error("bad evil bad!");
             if (res != null) throw new Error("already resolved!");
             if (p==null) throw new Error();
             if (p!=this) hp.add(p, true);
         }
         public Iterator<Body<T>> iterator() { return ((IterableForest<T>)resolve()).iterator(); }
         public HashSet<Tree<T>> expand(boolean toss) { return resolve().expand(toss); }
-        public boolean valid() { if (valid) return true; resolve(); return valid; }
         public String toString() { return resolve().toString(); }
         public Forest resolve() {
             if (hp==null) return res;
-            HashSet<Body> results = null;
             FastSet<Body> nh      = new FastSet<Body>();
             for(Forest<?> p : hp)
-                for(Body<?> b : (IterableForest<?>)p) {
-                    if (b.keep() && (b.creator==null || !b.creator.lame)) {
-                        valid = true;
-                        b.addTo(nh);
-                    } else {
-                        results = new HashSet<Body>();
-                    }
-                }
-            if (results != null) {
-                for(Forest<?> p : hp)
-                    for(Body<?> b : (IterableForest<?>)p)
-                        results.add(b);
-                for(Body b : results) {
-                    if (b.keep() && (b.creator==null || !b.creator.lame)) continue;
-                    if (b.creator!=null && b.creator.lame) continue;
-                    if (!b.keep(results)) continue;
-                    valid = true;
+                for(Body<?> b : (IterableForest<?>)p)
                     b.addTo(nh);
-                }
-            }
+            res = new MultiForest(nh);
             hp = null;
-            res = new MultiForest(nh, valid);
             return res;
         }
     }
@@ -188,13 +151,11 @@ public abstract class Forest<T> {
     // Implementations //////////////////////////////////////////////////////////////////////////////
 
     private static class MultiForest<T> extends IterableForest<T> {
+        public boolean empty() { return results.size()>0; }
         private final FastSet<Body<T>> results;
-        private boolean valid;
-        public boolean valid() { return valid; }
-        private MultiForest(FastSet<Body<T>> results, boolean valid) { this.results = results; this.valid = valid; }
+        private MultiForest(FastSet<Body<T>> results) { this.results = results; }
         public MultiForest(Token.Location loc, T tag, Forest<T>[] tokens, Sequence creator, boolean unwrap, boolean singleton) {
             this.results = new FastSet<Body<T>>(new Body(loc, tag, tokens, creator, unwrap, singleton));
-            this.valid = true;
         }
         public Iterator<Body<T>> iterator() { return results.iterator(); }