X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FParser.java;h=d04c49f21ca13468d8cf185c0e85b0b7c42c929b;hp=2a090b0cc8d9b36593d56586c82e54853cf3e119;hb=2fa0e673bf1813cce48ae7004e533a317d5f58e0;hpb=6c04c94d0eff9dc0fd1a0c2c36c8adc18f17d191

diff --git a/src/edu/berkeley/sbp/Parser.java b/src/edu/berkeley/sbp/Parser.java
index 2a090b0..d04c49f 100644
--- a/src/edu/berkeley/sbp/Parser.java
+++ b/src/edu/berkeley/sbp/Parser.java
@@ -11,15 +11,12 @@ public abstract class Parser<T extends Token, R> {
     private final Table pt;
 
     /** create a parser to parse the grammar with start symbol <tt>u</tt> */
-    protected Parser(Union u)  { this.pt = new Table(u, top()); }
-    protected Parser(Table pt) { this.pt = pt; }
+    protected Parser(Union u, Topology<T> top)  { this.pt = new Table(u, top); }
+    protected Parser(Table pt)                  { this.pt = pt; }
 
     /** implement this method to create the output forest corresponding to a lone shifted input token */
     public abstract Forest<R> shiftedToken(T t, Token.Location loc);
 
-    /** this method must return an empty topology of the input token type */
-    public abstract Topology<T> top();
-
     /** parse <tt>input</tt>, using the table <tt>pt</tt> to drive the parser */
     public Forest<R> parse(Token.Stream<T> input) throws IOException, ParseFailed {
         GSS gss = new GSS();
@@ -93,13 +90,11 @@ public abstract class Parser<T extends Token, R> {
 
                     if (isRightNullable(p)) {
                         Walk.Follow wf = new Walk.Follow(top.empty(), p.owner(), all_elements, cache);
-                        Reduction red = new Reduction(p);
-
                         Topology follow = wf.walk(p.owner());
                         for(Position p2 = p; p2 != null && p2.element() != null; p2 = p2.next())
                             follow = follow.intersect(new Walk.Follow(top.empty(), p2.element(), all_elements, cache).walk(p2.element()));
-                        state.reductions.put(follow, red);
-                        if (wf.includesEof()) state.eofReductions.add(red);
+                        state.reductions.put(follow, p);
+                        if (wf.includesEof()) state.eofReductions.add(p);
                     }
 
                     // if the element following this position is an atom, copy the corresponding
@@ -126,16 +121,16 @@ public abstract class Parser<T extends Token, R> {
             public  final     int               idx    = master_state_idx++;
             private final     HashSet<Position> hs;
 
-            private transient HashMap<Element,State>          gotoSetNonTerminals = new HashMap<Element,State>();
+            public transient HashMap<Element,State>          gotoSetNonTerminals = new HashMap<Element,State>();
             private transient TopologicalBag<Token,State>     gotoSetTerminals    = new TopologicalBag<Token,State>();
 
-            private           TopologicalBag<Token,Reduction> reductions          = new TopologicalBag<Token,Reduction>();
-            private           HashSet<Reduction>              eofReductions       = new HashSet<Reduction>();
+            private           TopologicalBag<Token,Position> reductions          = new TopologicalBag<Token,Position>();
+            private           HashSet<Position>              eofReductions       = new HashSet<Position>();
             private           TopologicalBag<Token,State>     shifts              = new TopologicalBag<Token,State>();
             private           boolean                         accept              = false;
 
             private VisitableMap<Token,State> oshifts = null;
-            private VisitableMap<Token,Reduction> oreductions = null;
+            private VisitableMap<Token,Position> oreductions = null;
 
             // Interface Methods //////////////////////////////////////////////////////////////////////////////
 
@@ -148,8 +143,8 @@ public abstract class Parser<T extends Token, R> {
             }
 
             boolean             canReduce(Token t)          { return t==null ? eofReductions.size()>0 : oreductions.contains(t); }
-            <B,C> void          invokeReductions(Token t, Invokable<Reduction,B,C> irbc, B b, C c) {
-                if (t==null) for(Reduction r : eofReductions) irbc.invoke(r, b, c);
+            <B,C> void          invokeReductions(Token t, Invokable<Position,B,C> irbc, B b, C c) {
+                if (t==null) for(Position r : eofReductions) irbc.invoke(r, b, c);
                 else         oreductions.invoke(t, irbc, b, c);
             }
 
@@ -244,77 +239,10 @@ public abstract class Parser<T extends Token, R> {
             public int compareTo(Table.State s) { return idx==s.idx ? 0 : idx < s.idx ? -1 : 1; }
             public int toInt() { return idx; }
         }
-
-        /**
-         *  the information needed to perform a reduction; copied here to
-         *  avoid keeping references to <tt>Element</tt> objects in a Table
-         */
-        public class Reduction {
-            // FIXME: cleanup; almost everything in here could go in either Sequence.Position.getRewrite() or else in GSS.Reduct
-            /*private*/ final Position position;
-            public int hashCode() { return position.hashCode(); }
-            public boolean equals(Object o) {
-                if (o==null) return false;
-                if (o==this) return true;
-                if (!(o instanceof Reduction)) return false;
-                Reduction r = (Reduction)o;
-                return r.position == position;
-            }
-            public Reduction(Position p) {
-                this.position = p;
-            }
-            public String toString() { return "[reduce " + position + "]"; }
-
-            private Forest zero = null;
-            public Forest zero() {
-                if (zero != null) return zero;
-                if (position.pos > 0) throw new Error();
-                return zero = position.rewrite(null);
-            }
-
-            public void reduce(GSS.Phase.Node parent, GSS.Phase.Node onlychild) {
-                Forest[] holder = new Forest[position.pos];
-                if (position.pos<=0) throw new Error("called wrong form of reduce()");
-                int pos = position.pos-1;
-                Forest old = holder[pos];
-                holder[pos] = parent.pending();
-                if (pos==0) {
-                    System.arraycopy(holder, 0, position.holder, 0, holder.length);
-                    finish(onlychild, position.rewrite(parent.phase().getLocation()), parent.phase(), holder);
-                } else {
-                    reduce(onlychild, pos-1, parent.phase(), holder);
-                }
-                holder[pos] = old;
-            }
-
-            // FIXME: this could be more elegant and/or cleaner and/or somewhere else
-            public void reduce(GSS.Phase.Node parent, int pos, GSS.Phase target, Forest[] holder) {
-                Forest old = holder[pos];
-                holder[pos] = parent.pending();
-                if (pos==0) {
-                    System.arraycopy(holder, 0, position.holder, 0, holder.length);
-                    for(int i=0; i<position.pos; i++) if (position.holder[i]==null) throw new Error("realbad");
-                    Forest rex = position.rewrite(target.getLocation());
-                    for(GSS.Phase.Node child : parent.parents()) finish(child, rex, target, holder);
-                } else {
-                    for(GSS.Phase.Node child : parent.parents()) reduce(child, pos-1, target, holder);
-                }
-                holder[pos] = old;
-            }
-            public void finish(GSS.Phase.Node parent, Forest result, GSS.Phase target, Forest[] holder) {
-                State state = parent.state.gotoSetNonTerminals.get(position.owner());
-                if (result==null) throw new Error();
-                if (state!=null)
-                    target.newNode(parent, result, state, position.pos<=0, this);
-            }
-        }
     }
 
-    private static final Forest[] emptyForestArray = new Forest[0];
-
-
     // Helpers //////////////////////////////////////////////////////////////////////////////
-
+    
     private static void reachable(Element e, HashSet<Position> h) {
         if (e instanceof Atom) return;
         for(Sequence s : ((Union)e))