checkpoint harmony
[sbp.git] / src / edu / berkeley / sbp / Parser.java
index f087a05..cbf9b47 100644 (file)
@@ -11,7 +11,7 @@ import java.lang.reflect.*;
 /** a parser which translates streams of Tokens of type T into a Forest<R> */
 public abstract class Parser<T extends Token, R> {
 
-    private final Table pt;
+    public 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()); }
@@ -36,16 +36,16 @@ public abstract class Parser<T extends Token, R> {
     public Forest<R> parse(Token.Stream<T> input) throws IOException, Failed {
         GSS gss = new GSS();
         Token.Location loc = input.getLocation();
-        GSS.Phase current = gss.new Phase(null, input.next(), loc);
-        current.newNode(null, null, pt.start, true, null);
+        GSS.Phase current = gss.new Phase(null, this, null, input.next(1, 0, 0), loc, null);
+        current.newNode(null, Forest.leaf(null, null), pt.start, true);
+        int count = 1;
         for(;;) {
             loc = input.getLocation();
-            GSS.Phase next = gss.new Phase(current, input.next(), loc);
             current.reduce();
             Forest forest = current.token==null ? null : shiftedToken((T)current.token, loc);
-            current.shift(next, forest);
+            GSS.Phase next = gss.new Phase(current, this, current, input.next(count, gss.resets, gss.waits), loc, forest);
+            count = next.hash.size();
             if (current.isDone()) return (Forest<R>)current.finalResult;
-            current.checkFailure();
             current = next;
         }
     }
@@ -53,13 +53,13 @@ public abstract class Parser<T extends Token, R> {
 
     // Exceptions //////////////////////////////////////////////////////////////////////////////
 
-    public static class Failed extends Exception {
+    public static class Failed extends RuntimeException {
         private final Token.Location location;
         private final String         message;
         public Failed() { this("", null); }
         public Failed(String message, Token.Location loc) { this.location = loc; this.message = message; }
         public Token.Location getLocation() { return location; }
-        public String toString() { return message + (location==null ? "" : (" at " + location)); }
+        public String toString() { return message/* + (location==null ? "" : (" at " + location))*/; }
     }
 
     public static class Ambiguous extends RuntimeException {
@@ -81,6 +81,8 @@ public abstract class Parser<T extends Token, R> {
     static class Table extends Walk.Cache {
 
         public final Walk.Cache cache = this;
+
+        public HashMapBag<Position,State> byPosition = new HashMapBag<Position,State>();
         
         private void walk(Element e, HashSet<Element> hs) {
             if (e==null) return;
@@ -128,12 +130,22 @@ public abstract class Parser<T extends Token, R> {
                     if (start0.contains(p.owner()) && p.next()==null)
                         state.accept = true;
 
-                    // FIXME: how does right-nullability interact with follow restrictions?
-                    // all right-nullable rules get a reduction [Johnstone 2000]
                     if (p.isRightNullable(cache)) {
                         Walk.Follow wf = new Walk.Follow(top.empty(), p.owner(), all_elements, cache);
                         Reduction red = new Reduction(p);
-                        state.reductions.put(wf.walk(p.owner()), red);
+
+                        Topology follow = wf.walk(p.owner());
+                        if (p.owner() instanceof Sequence.RewritingSequence &&
+                            (((Sequence.RewritingSequence)p.owner()).tag+"").equals("emailaddr")) {
+                            System.out.println("follow before: " + new edu.berkeley.sbp.misc.CharToken.CharRange(follow));
+                        }
+                        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()));
+                        if (p.owner() instanceof Sequence.RewritingSequence &&
+                            (((Sequence.RewritingSequence)p.owner()).tag+"").equals("emailaddr")) {
+                            System.out.println("follow after: " + new edu.berkeley.sbp.misc.CharToken.CharRange(follow));
+                        }
+                        state.reductions.put(follow, red);
                         if (wf.includesEof()) state.eofReductions.add(red);
                     }
 
@@ -142,11 +154,25 @@ public abstract class Parser<T extends Token, R> {
                     if (p.element() != null && p.element() instanceof Atom)
                         state.shifts.addAll(state.gotoSetTerminals.subset(((Atom)p.element())));
                 }
+            for(State state : all_states.values()) {
+                state.oreductions = state.reductions.optimize();
+                state.oshifts = state.shifts.optimize();
+            }
         }
 
         /** a single state in the LR table and the transitions possible from it */
-        public class State implements Comparable<Table.State>, Iterable<Position> {
+
+        public class State implements Comparable<Table.State>, IntegerMappable, Iterable<Position> {
         
+            public int toInt() { return idx; }
+
+            public boolean lame() {
+                for(Position p : this)
+                    for(Position p2 = p; p2!=null; p2=p2.next())
+                        if (p2.isLast() && !p2.owner().lame)
+                            return false;
+                return true;
+            }
             /*
             public boolean isResolvable(Token t) {
                 boolean found = false;
@@ -179,15 +205,26 @@ public abstract class Parser<T extends Token, R> {
             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;
+
             // Interface Methods //////////////////////////////////////////////////////////////////////////////
 
-            public boolean             canShift(Token t)           { return shifts.contains(t); }
-            public Iterable<State>     getShifts(Token t)          { return shifts.get(t); }
             public boolean             isAccepting()               { return accept; }
-            public Iterable<Reduction> getReductions(Token t)      { return t==null ? eofReductions : reductions.get(t); }
-            public Iterable<Reduction> getEofReductions()          { return eofReductions; }
+
+            public boolean             canShift(Token t)           { return oshifts.contains(t); }
+            public boolean             canReduce(Token t)          { return t==null ? eofReductions.size()>0 : oreductions.contains(t); }
+
             public Iterator<Position>  iterator()                  { return hs.iterator(); }
 
+            public <B,C> void          invokeShifts(Token t, Invokable<State,B,C> irbc, B b, C c) {
+                oshifts.invoke(t, irbc, b, c);
+            }
+            public <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);
+                else         oreductions.invoke(t, irbc, b, c);
+            }
+
             // Constructor //////////////////////////////////////////////////////////////////////////////
 
             /**
@@ -220,6 +257,7 @@ public abstract class Parser<T extends Token, R> {
                 // register ourselves in the all_states hash so that no
                 // two states are ever created with an identical position set
                 all_states.put(hs, this);
+                for(Position p : hs) byPosition.add(p,this);
 
                 // Step 1a: examine all Position's in this state and compute the mappings from
                 //          sets of follow tokens (tokens which could follow this position) to sets
@@ -282,7 +320,13 @@ public abstract class Parser<T extends Token, R> {
                 }
             }
 
-            public String toString() { return "state["+idx+"]"; }
+            public String toString() {
+                //return "state["+idx+"]";
+                StringBuffer ret = new StringBuffer();
+                ret.append("state["+idx+"]: ");
+                for(Position p : this) ret.append("{"+p+"}  ");
+                return ret.toString();
+            }
 
             public int compareTo(Table.State s) { return idx==s.idx ? 0 : idx < s.idx ? -1 : 1; }
         }
@@ -311,24 +355,6 @@ public abstract class Parser<T extends Token, R> {
             }
             public String toString() { return "[reduce " + position + "]"; }
 
-            public Forest reduce(GSS.Phase.Node parent, GSS.Phase.Node onlychild, Forest rex) {
-                Forest ret = reduce(parent, numPop-1, rex, onlychild, parent.phase());
-                return ret;
-            }
-
-            public Forest reduce(GSS.Phase.Node parent, GSS.Phase.Node onlychild) {
-                int pos = numPop-1;
-                if (pos>=0) holder[pos] = parent.pending();
-                Forest rex = null;
-                if (pos==0) {
-                    if (rex==null) {
-                        System.arraycopy(holder, 0, position.holder, 0, holder.length);
-                        rex = position.rewrite(parent.phase().getLocation());
-                    }
-                }
-                return reduce(onlychild, pos-1, rex, null, parent.phase());
-            }
-
             private Forest zero = null;
             public Forest zero() {
                 if (zero != null) return zero;
@@ -336,31 +362,44 @@ public abstract class Parser<T extends Token, R> {
                 return zero = position.rewrite(null);
             }
 
+            public void reduce(GSS.Phase.Node parent) {
+                if (numPop==0) finish(parent, zero(), parent.phase());
+                else           reduce(parent, numPop-1, parent.phase());
+            }
+
+            public void reduce(GSS.Phase.Node parent, GSS.Phase.Node onlychild) {
+                if (numPop<=0) throw new Error("called wrong form of reduce()");
+                int pos = numPop-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());
+                } else {
+                    reduce(onlychild, pos-1, parent.phase());
+                }
+                holder[pos] = old;
+            }
+
             // FIXME: this could be more elegant and/or cleaner and/or somewhere else
-            private Forest reduce(GSS.Phase.Node parent, int pos, Forest rex, GSS.Phase.Node onlychild, GSS.Phase target) {
-                if (pos>=0) holder[pos] = parent.pending();
+            private void reduce(GSS.Phase.Node parent, int pos, GSS.Phase target) {
+                Forest old = holder[pos];
+                holder[pos] = parent.pending();
                 if (pos==0) {
-                    if (rex==null) {
-                        System.arraycopy(holder, 0, position.holder, 0, holder.length);
-                        rex = position.rewrite(target.getLocation());
-                    }
-                    if (onlychild != null)
-                        reduce(onlychild, pos-1, rex, null, target);
-                    else 
-                        for(GSS.Phase.Node child : parent.parents())
-                            reduce(child, pos-1, rex, null, target);
-                } else if (pos>0) {
-                    if (onlychild != null)
-                        reduce(onlychild, pos-1, rex, null, target);
-                    else 
-                        for(GSS.Phase.Node child : parent.parents())
-                            reduce(child, pos-1, rex, null, target);
+                    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);
                 } else {
-                    State state = parent.state.gotoSetNonTerminals.get(position.owner());
-                    if (state!=null)
-                        target.newNode(parent, rex, state, numPop<=0, parent.phase());
+                    for(GSS.Phase.Node child : parent.parents()) reduce(child, pos-1, target);
                 }
-                return rex;
+                holder[pos] = old;
+            }
+            private void finish(GSS.Phase.Node parent, Forest result, GSS.Phase target) {
+                State state = parent.state.gotoSetNonTerminals.get(position.owner());
+                if (result==null) throw new Error();
+                if (state!=null)
+                    target.newNode(parent, result, state, numPop<=0, this);
             }
         }
     }