X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FParser.java;h=d04c49f21ca13468d8cf185c0e85b0b7c42c929b;hp=b4ac23a0a3285023df34427c262e921a9411e241;hb=2fa0e673bf1813cce48ae7004e533a317d5f58e0;hpb=cd979dfc5968a185c12d6eedc2aa688ef4b0f8b8

diff --git a/src/edu/berkeley/sbp/Parser.java b/src/edu/berkeley/sbp/Parser.java
index b4ac23a..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
@@ -129,13 +124,13 @@ public abstract class Parser<T extends Token, R> {
             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);
             }
 
@@ -244,42 +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);
-            }
-
-        }
     }
 
-    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))