X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FParser.java;h=65f3dc3e9e3f17b80be3d03950ffc9d22ddc0901;hp=3fad1ddacd8c1e7a257d17193b9fcff3973b24b4;hb=b0ec1efcb13eceb539f9cd033a0d2908fc2be27a;hpb=72d5880c192b7fbd525c97ded4cf11e935c58cc8

diff --git a/src/edu/berkeley/sbp/Parser.java b/src/edu/berkeley/sbp/Parser.java
index 3fad1dd..65f3dc3 100644
--- a/src/edu/berkeley/sbp/Parser.java
+++ b/src/edu/berkeley/sbp/Parser.java
@@ -22,7 +22,15 @@ public abstract class Parser<T extends Token, R> {
 
 
     /** parse <tt>input</tt> for a exactly one unique result, throwing <tt>Ambiguous</tt> if not unique or <tt>Failed</tt> if none */
-    public Tree<R> parse1(Token.Stream<T> input) throws IOException, Failed, Ambiguous { return parse(input).expand1(); }
+    public Tree<R> parse1(Token.Stream<T> input) throws IOException, Failed, Ambiguous {
+        Forest<R> ret = parse(input);
+        try { return ret.expand1(); }
+        catch (Ambiguous a) {
+            System.out.println("while expanding:");
+            System.out.println(ret);
+            throw a;
+        }
+    }
 
     /** parse <tt>input</tt>, using the table <tt>pt</tt> to drive the parser */
     public Forest<R> parse(Token.Stream<T> input) throws IOException, Failed {
@@ -126,7 +134,7 @@ public abstract class Parser<T extends Token, R> {
                         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);
-                        if (wf.includesEof()) state.eofReductions.add(red, true);
+                        if (wf.includesEof()) state.eofReductions.add(red);
                     }
 
                     // if the element following this position is an atom, copy the corresponding
@@ -139,14 +147,35 @@ public abstract class Parser<T extends Token, R> {
         /** a single state in the LR table and the transitions possible from it */
         public class State implements Comparable<Table.State>, Iterable<Position> {
         
-            public final      int               idx    = master_state_idx++;
+            /*
+            public boolean isResolvable(Token t) {
+                boolean found = false;
+                for(Reduction r : getReductions(t)) {
+                    Position p = r.position;
+                    if (!p.isRightNullable(cache)) continue;
+                    if (p.owner().firstp()==p) continue;
+                    if (found) {
+                        // found two items meeting criteria #1
+                        return false;
+                    } else {
+                        found = true;
+                        continue;
+                    }
+                    if (p.element()==null) continue;
+                    Topology first = new Walk.First(top(), cache).walk(p.element());
+                    if (first.contains(t))
+                }
+            }
+            */
+
+            public  final     int               idx    = master_state_idx++;
             private final     HashSet<Position> hs;
 
             private 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           FastSet<Reduction>              eofReductions       = new FastSet<Reduction>();
+            private           HashSet<Reduction>              eofReductions       = new HashSet<Reduction>();
             private           TopologicalBag<Token,State>     shifts              = new TopologicalBag<Token,State>();
             private           boolean                         accept              = false;
 
@@ -155,7 +184,7 @@ public abstract class Parser<T extends Token, R> {
             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 reductions.get(t); }
+            public Iterable<Reduction> getReductions(Token t)      { return t==null ? eofReductions : reductions.get(t); }
             public Iterable<Reduction> getEofReductions()          { return eofReductions; }
             public Iterator<Position>  iterator()                  { return hs.iterator(); }
 
@@ -265,7 +294,7 @@ public abstract class Parser<T extends Token, R> {
         public class Reduction {
             // FIXME: cleanup; almost everything in here could go in either Sequence.Position.getRewrite() or else in GSS.Reduct
             public final int numPop;
-            private final Position position;
+            /*private*/ final Position position;
             private final Forest[] holder;    // to avoid constant reallocation
             public int hashCode() { return position.hashCode(); }
             public boolean equals(Object o) {
@@ -281,34 +310,51 @@ public abstract class Parser<T extends Token, R> {
                 this.holder = new Forest[numPop];
             }
             public String toString() { return "[reduce " + position + "]"; }
-            public Forest reduce(Forest f, GSS.Phase.Node parent, GSS.Phase.Node onlychild, GSS.Phase target, Forest rex) {
-                holder[numPop-1] = f;
-                return reduce(parent, numPop-2, rex, onlychild, target);                
+
+            public Forest reduce(GSS.Phase.Node parent) {
+                if (numPop==0) return finish(parent, zero(), parent.phase());
+                return reduce(parent, numPop-1, null, parent.phase());
             }
-            public Forest reduce(GSS.Phase.Node parent, GSS.Phase.Node onlychild, GSS.Phase target, Forest rex) {
-                return reduce(parent, numPop-1, rex, onlychild, target);
+
+            public Forest reduce(GSS.Phase.Node parent, GSS.Phase.Node onlychild) {
+                if (numPop<=0) throw new Error("called wrong form of reduce()");
+                int pos = numPop-1;
+                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, parent.phase());
+            }
+
+            private Forest zero = null;
+            public Forest zero() {
+                if (zero != null) return zero;
+                if (numPop > 0) throw new Error();
+                return zero = position.rewrite(null);
             }
 
             // 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();
-                if (pos<=0 && rex==null) {
+            private Forest reduce(GSS.Phase.Node parent, int pos, Forest rex, GSS.Phase target) {
+                if (pos<0) return finish(parent, rex, target);
+                holder[pos] = parent.pending();
+                if (pos==0 && rex==null) {
                     System.arraycopy(holder, 0, position.holder, 0, holder.length);
                     rex = position.rewrite(target.getLocation());
                 }
-                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);
-                } 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, rex, target);
                 return rex;
             }
+            private Forest finish(GSS.Phase.Node parent, Forest result, GSS.Phase target) {
+                State state = parent.state.gotoSetNonTerminals.get(position.owner());
+                if (state!=null)
+                    target.newNode(parent, result, state, numPop<=0, parent.phase());
+                return result;
+            }
         }
     }