From 39ab0c455ee3e3833a4e75529fce9af661ae6fe3 Mon Sep 17 00:00:00 2001
From: adam <adam@megacz.com>
Date: Wed, 4 Jan 2006 03:43:08 -0500
Subject: [PATCH 1/1] checkpoint

darcs-hash:20060104084308-5007d-7daa9e77c69ab2e108d4eefef031380cbf48ddb9.gz
---
 src/edu/berkeley/sbp/GSS.java      |   35 +++++++++++++++++++++--------------
 src/edu/berkeley/sbp/Sequence.java |   18 ++++++++++++++++--
 2 files changed, 37 insertions(+), 16 deletions(-)

diff --git a/src/edu/berkeley/sbp/GSS.java b/src/edu/berkeley/sbp/GSS.java
index dcc8f33..4970936 100644
--- a/src/edu/berkeley/sbp/GSS.java
+++ b/src/edu/berkeley/sbp/GSS.java
@@ -115,14 +115,15 @@ class GSS {
             if (!fromEmptyReduction) n.queueReductions();
         }
 
+        
+        boolean reducing = false;
         /** perform all reduction operations */
         public void reduce() {
+            reducing = true;
             HashSet<Phase.Node> s = new HashSet<Phase.Node>();
             s.addAll(hash.values());
-            for(Phase.Node n : s) {
-                n.queueEmptyReductions();
-                n.queueReductions();
-            }
+            for(Phase.Node n : s) n.queueEmptyReductions();
+            for(Phase.Node n : s) n.queueReductions();
             while(pendingReduct.size()>0)
                 //pendingReduct.iterator().next().go();
                 pendingReduct.removeFirst().go();
@@ -134,6 +135,7 @@ class GSS {
             Forest res = null;
             boolean ok = false;
             for(Phase.Node n : hash.values()) {
+                if (n.holder==null) continue;
                 n.holder.resolve();
                 if (token == null && n.state.isAccepting()) {
                     ok = true;
@@ -154,10 +156,10 @@ class GSS {
                 error.append("error: unable to shift token \"" + token + "\"\n");
                 error.append("  before: " +pendingReductions+ "\n");
                 error.append("  before: " +totalReductions+ "\n");
-                for(Phase.Node n : hash.values()) {
-                    n.queueReductions();
-                    n.queueEmptyReductions();
-                }
+                //for(Phase.Node n : hash.values()) {
+                //n.queueReductions();
+                //n.queueEmptyReductions();
+                //}
                 error.append("  after: " +pendingReductions+ "\n");
                 error.append("  candidate states:\n");
                 for(Phase.Node n : hash.values()) {
@@ -213,9 +215,14 @@ class GSS {
 
             /** FIXME */
             public void queueEmptyReductions() {
-                for(Parser.Table.Reduction r : token==null ? state.getEofReductions() : state.getReductions(token)) {
-                    if (r.numPop==0)
-                        newReduct(this, null, r);   /* ALLOC */
+                if (reducing) {
+                    for(Parser.Table.Reduction r : token==null ? state.getEofReductions() : state.getReductions(token)) {
+                        if (r.numPop==0) {
+                            //r.reduce(this, null, this.phase, r.zero());
+                            Reduct red = new Reduct(this, null, r);
+                            red.go();   /* ALLOC */
+                        }
+                    }
                 }
             }
 
@@ -282,7 +289,7 @@ class GSS {
                         // created node rather than part of the popped
                         // sequence
                         
-                        if (r.numPop == 1) new Reduct(n, n2, r).go();
+                        if (r.numPop == 1) new Reduct(n, n2, r)/*.go()*/;
                     }
 
 
@@ -295,7 +302,7 @@ class GSS {
                 } else if (r.numPop==0) { r.reduce(n, n2, n.phase, r.zero());
                 } else if (r.numPop==1) {
                     // UGLY HACK
-                    // The problem here is that a "reduction of length 0/1"
+                    // The problem here is that a "reduction of length 1"
                     // performed twice with different values of n2 needs
                     // to only create a *single* new result, but must add
                     // multiple parents to the node holding that result.
@@ -338,5 +345,5 @@ class GSS {
     private static long code(Parser.Table.State state, Phase start) {
         return (((long)state.idx) << 32) | (start==null ? 0 : start.pos);
     }
-
+    public boolean yak = false;
 }
diff --git a/src/edu/berkeley/sbp/Sequence.java b/src/edu/berkeley/sbp/Sequence.java
index 39e4b11..ee3fd4b 100644
--- a/src/edu/berkeley/sbp/Sequence.java
+++ b/src/edu/berkeley/sbp/Sequence.java
@@ -60,7 +60,17 @@ public abstract class Sequence extends Element implements Iterable<Element> {
         this.firstp = new Position(0);
     }
 
-    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();
+            Forest fo = firstp().rewrite(null);
+            epsilonForm.merge(fo);
+        }
+        return epsilonForm;
+    }
 
     protected abstract <T> Forest<T> postReduce(Token.Location loc, Forest<T>[] args);
 
@@ -101,10 +111,13 @@ public abstract class Sequence extends Element implements Iterable<Element> {
 
         // Reduction /////////////////////////////////////////////////////////////////////////////////
 
-        <T> Forest<T> rewrite(Token.Location loc) {
+        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();
             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; }
             return ret;
         }
 
@@ -190,6 +203,7 @@ 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];
+            //System.out.println("reduce \""+tag+"\"");
             return Forest.create(loc, (T)tag, args2, this, false, false);
         }
         public StringBuffer toString(StringBuffer sb, boolean spacing) {
-- 
1.7.10.4