X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FParser.java;h=2344e15b96c2cb9f451c27f248edc3e04c15978f;hp=24f8410d0d5f521a19cc47b2091dc65b69d447b1;hb=ae0cef03f2e46f6ae6438f9a3e60ca36ff1a4643;hpb=37d28a2fa4ecc9534ca03827c23fdb493af79645

diff --git a/src/edu/berkeley/sbp/Parser.java b/src/edu/berkeley/sbp/Parser.java
index 24f8410..2344e15 100644
--- a/src/edu/berkeley/sbp/Parser.java
+++ b/src/edu/berkeley/sbp/Parser.java
@@ -6,34 +6,46 @@ import java.io.*;
 import java.util.*;
 
 /** a parser which translates streams of Tokens of type T into a Forest<R> */
-public abstract class Parser<T extends Token, R> {
+public abstract class Parser<Tok, Result> {
 
-    private final Table pt;
+    protected final Table<Tok> 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<Tok> top)  { this.pt = new Table<Tok>(u, top); }
+    protected Parser(Table<Tok> 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);
+    protected abstract Forest<Result> shiftToken(Tok t, Input.Location newloc);
 
-    /** this method must return an empty topology of the input token type */
-    public abstract Topology<T> top();
+    boolean helpgc = true;
+
+    public String toString() { return pt.toString(); }
 
     /** 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 {
+    public Forest<Result> parse(Input<Tok> input) throws IOException, ParseFailed {
         GSS gss = new GSS();
-        Token.Location loc = input.getLocation();
-        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);
+        Input.Location loc = input.getLocation();
+        GSS.Phase current = gss.new Phase<Tok>(null, this, null, input.next(), loc, null);
+        current.newNode(null, Forest.create(null, null, null, false), pt.start, true);
         int count = 1;
-        for(;;) {
+        for(int idx=0;;idx++) {
+            Input.Location oldloc = loc;
             loc = input.getLocation();
             current.reduce();
-            Forest forest = current.token==null ? null : shiftedToken((T)current.token, loc);
-            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;
+            Forest forest = current.token==null ? null : shiftToken((Tok)current.token, loc);
+            GSS.Phase next = gss.new Phase<Tok>(current, this, current, input.next(), loc, forest);
+            if (!helpgc) {
+                FileOutputStream fos = new FileOutputStream("out-"+idx+".dot");
+                PrintWriter p = new PrintWriter(new OutputStreamWriter(fos));
+                GraphViz gv = new GraphViz();
+                for(Object n : next)
+                    ((GSS.Phase.Node)n).toGraphViz(gv);
+                gv.dump(p);
+                p.flush();
+                p.close();
+            }
+            count = next.size();
+            if (current.isDone()) return (Forest<Result>)gss.finalResult;
             current = next;
         }
     }
@@ -41,7 +53,27 @@ public abstract class Parser<T extends Token, R> {
     // Table //////////////////////////////////////////////////////////////////////////////
 
     /** an SLR(1) parse table which may contain conflicts */
-    static class Table extends Walk.Cache {
+    static class Table<Tok> extends Walk.Cache {
+
+        public String toString() {
+            StringBuffer sb = new StringBuffer();
+            sb.append("parse table");
+            for(State<Tok> state : all_states.values()) {
+                sb.append("  " + state + "\n");
+                for(Topology<Tok> t : state.shifts) {
+                    sb.append("      shift  \""+
+                              new edu.berkeley.sbp.chr.CharTopology((IntegerTopology<Character>)t)+"\" => ");
+                    for(State st : state.shifts.getAll(t))
+                        sb.append(st.idx+"  ");
+                    sb.append("\n");
+                }
+                for(Topology<Tok> t : state.reductions)
+                    sb.append("      reduce \""+
+                              new edu.berkeley.sbp.chr.CharTopology((IntegerTopology<Character>)t)+"\" => " +
+                              state.reductions.getAll(t) + "\n");
+            }
+            return sb.toString();
+        }
 
         public final Walk.Cache cache = this;
 
@@ -50,41 +82,50 @@ public abstract class Parser<T extends Token, R> {
             if (hs.contains(e)) return;
             hs.add(e);
             if (e instanceof Atom) return;
-            for(Sequence s : (Union)e) {
-                hs.add(s);
-                for(Position p = s.firstp(); p != null; p = p.next())
-                    walk(p.element(), hs);
-            }
+            for(Sequence s : (Union)e)
+                walk(s, hs);
+        }
+        private void walk(Sequence s, HashSet<Element> hs) {
+            hs.add(s);
+            for(Position p = s.firstp(); p != null; p = p.next())
+                walk(p.element(), hs);
+            for(Sequence ss : s.needs()) walk(ss, hs);
+            for(Sequence ss : s.hates()) walk(ss, hs);
         }
 
         /** the start state */
-        public final State   start;
+        public  final State<Tok>   start;
+
+        /** the state from which no reductions can be done */
+        private final State<Tok>   dead_state;
 
         /** used to generate unique values for State.idx */
         private int master_state_idx = 0;
+        HashMap<HashSet<Position>,State<Tok>>   all_states    = new HashMap<HashSet<Position>,State<Tok>>();
 
         /** construct a parse table for the given grammar */
         public Table(Topology top) { this("s", top); }
         public Table(String startSymbol, Topology top) { this(new Union(startSymbol), top); }
         public Table(Union ux, Topology top) {
             Union start0 = new Union("0");
-            start0.add(new Sequence.Singleton(ux, null, null));
+            start0.add(new Sequence.Singleton(ux));
 
             for(Sequence s : start0) cache.eof.put(s, true);
             cache.eof.put(start0, true);
 
             // construct the set of states
-            HashMap<HashSet<Position>,State>   all_states    = new HashMap<HashSet<Position>,State>();
-            HashSet<Element>                   all_elements  = new HashSet<Element>();
+            HashSet<Element>                        all_elements  = new HashSet<Element>();
             walk(start0, all_elements);
             for(Element e : all_elements)
                 cache.ys.addAll(e, new Walk.YieldSet(e, cache).walk());
             HashSet<Position> hp = new HashSet<Position>();
             reachable(start0, hp);
-            this.start = new State(hp, all_states, all_elements);
+
+            this.dead_state = new State<Tok>(new HashSet<Position>(), all_states, all_elements);
+            this.start = new State<Tok>(hp, all_states, all_elements);
 
             // for each state, fill in the corresponding "row" of the parse table
-            for(State state : all_states.values())
+            for(State<Tok> state : all_states.values())
                 for(Position p : state.hs) {
 
                     // the Grammar's designated "last position" is the only accepting state
@@ -93,13 +134,11 @@ 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
@@ -107,50 +146,50 @@ 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();
-            }
+            if (top instanceof IntegerTopology)
+                for(State<Tok> state : all_states.values()) {
+                    state.oreductions = state.reductions.optimize(((IntegerTopology)top).functor());
+                    state.oshifts = state.shifts.optimize(((IntegerTopology)top).functor());
+                }
         }
 
         private boolean isRightNullable(Position p) {
             if (p.isLast()) return true;
-            if (!p.element().possiblyEpsilon(this)) return false;
+            if (!possiblyEpsilon(p.element())) return false;
             return isRightNullable(p.next());
         }
 
         /** a single state in the LR table and the transitions possible from it */
 
-        public class State implements Comparable<Table.State>, IntegerMappable, Iterable<Position> {
+        class State<Tok> implements Comparable<State<Tok>>, IntegerMappable, Iterable<Position> {
         
             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>();
+            public transient HashMap<Element,State<Tok>>          gotoSetNonTerminals = new HashMap<Element,State<Tok>>();
+            private transient TopologicalBag<Tok,State<Tok>>     gotoSetTerminals    = new TopologicalBag<Tok,State<Tok>>();
 
-            private           TopologicalBag<Token,Reduction> reductions          = new TopologicalBag<Token,Reduction>();
-            private           HashSet<Reduction>              eofReductions       = new HashSet<Reduction>();
-            private           TopologicalBag<Token,State>     shifts              = new TopologicalBag<Token,State>();
+            private           TopologicalBag<Tok,Position> reductions          = new TopologicalBag<Tok,Position>();
+            private           HashSet<Position>              eofReductions       = new HashSet<Position>();
+            private           TopologicalBag<Tok,State<Tok>>     shifts              = new TopologicalBag<Tok,State<Tok>>();
             private           boolean                         accept              = false;
 
-            private VisitableMap<Token,State> oshifts = null;
-            private VisitableMap<Token,Reduction> oreductions = null;
+            private VisitableMap<Tok,State<Tok>> oshifts = null;
+            private VisitableMap<Tok,Position> oreductions = null;
 
             // Interface Methods //////////////////////////////////////////////////////////////////////////////
 
-            public boolean             isAccepting()               { return accept; }
-
-            public boolean             canShift(Token t)           { return oshifts.contains(t); }
-            public boolean             canReduce(Token t)          { return t==null ? eofReductions.size()>0 : oreductions.contains(t); }
+            boolean             isAccepting()           { return accept; }
+            public Iterator<Position>  iterator()       { return hs.iterator(); }
 
-            public Iterator<Position>  iterator()                  { return hs.iterator(); }
-
-            public <B,C> void          invokeShifts(Token t, Invokable<State,B,C> irbc, B b, C c) {
+            boolean             canShift(Tok t)         { return oshifts!=null && oshifts.contains(t); }
+            <B,C> void          invokeShifts(Tok t, Invokable<State<Tok>,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);
+
+            boolean             canReduce(Tok t)        { return oreductions != null && (t==null ? eofReductions.size()>0 : oreductions.contains(t)); }
+            <B,C> void          invokeReductions(Tok 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);
             }
 
@@ -179,7 +218,7 @@ public abstract class Parser<T extends Token, R> {
              *  </ul>
              */
             public State(HashSet<Position> hs,
-                         HashMap<HashSet<Position>,State> all_states,
+                         HashMap<HashSet<Position>,State<Tok>> all_states,
                          HashSet<Element> all_elements) {
                 this.hs = hs;
 
@@ -192,7 +231,7 @@ public abstract class Parser<T extends Token, R> {
                 //          of _new_ positions (positions after shifting).  These mappings are
                 //          collectively known as the _closure_
 
-                TopologicalBag<Token,Position> bag0 = new TopologicalBag<Token,Position>();
+                TopologicalBag<Tok,Position> bag0 = new TopologicalBag<Tok,Position>();
                 for(Position position : hs) {
                     if (position.isLast() || !(position.element() instanceof Atom)) continue;
                     Atom a = (Atom)position.element();
@@ -205,10 +244,10 @@ public abstract class Parser<T extends Token, R> {
                 //          set, add that character set to the goto table (with the State corresponding to the
                 //          computed next-position set).
 
-                for(Topology<Token> r : bag0) {
+                for(Topology<Tok> r : bag0) {
                     HashSet<Position> h = new HashSet<Position>();
                     for(Position p : bag0.getAll(r)) h.add(p);
-                    gotoSetTerminals.put(r, all_states.get(h) == null ? new State(h, all_states, all_elements) : all_states.get(h));
+                    gotoSetTerminals.put(r, all_states.get(h) == null ? new State<Tok>(h, all_states, all_elements) : all_states.get(h));
                 }
 
                 // Step 2: for every non-Atom element (ie every Element which has a corresponding reduction),
@@ -218,6 +257,7 @@ public abstract class Parser<T extends Token, R> {
                 //         "yields" [in one or more step] is used instead of "produces" [in exactly one step]
                 //         to avoid having to iteratively construct our set of States as shown in most
                 //         expositions of the algorithm (ie "keep doing XYZ until things stop changing").
+
                 HashMapBag<Element,Position> move = new HashMapBag<Element,Position>();
                 for(Position p : hs) {
                     Element e = p.element();
@@ -230,105 +270,46 @@ public abstract class Parser<T extends Token, R> {
                 }
                 for(Element y : move) {
                     HashSet<Position> h = move.getAll(y);
-                    State s = all_states.get(h) == null ? new State(h, all_states, all_elements) : all_states.get(h);
-                    gotoSetNonTerminals.put(y, s);
+                    State<Tok> s = all_states.get(h) == null ? new State<Tok>(h, all_states, all_elements) : all_states.get(h);
+                    // if a reduction is "lame", it should wind up in the dead_state after reducing
+                    if (y instanceof Sequence && ((Sequence)y).lame)
+                        ((HashMap)gotoSetNonTerminals).put(y, dead_state);
+                    else
+                        gotoSetNonTerminals.put(y, s);
                 }
             }
 
+            public String toStringx() {
+                StringBuffer st = new StringBuffer();
+                for(Position p : this) {
+                    if (st.length() > 0) st.append("\n");
+                    st.append(p);
+                }
+                return st.toString();
+            }
             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; }
+            public int compareTo(State<Tok> 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
-            public final int numPop;
-            /*private*/ final Position position;
-            private final Forest[] holder;    // to avoid constant reallocation
-            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;
-                this.numPop = p.pos;
-                this.holder = new Forest[numPop];
-            }
-            public String toString() { return "[reduce " + position + "]"; }
-
-            private Forest zero = null;
-            public Forest zero() {
-                if (zero != null) return zero;
-                if (numPop > 0) throw new Error();
-                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 void reduce(GSS.Phase.Node parent, int pos, GSS.Phase target) {
-                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);
-                } else {
-                    for(GSS.Phase.Node child : parent.parents()) reduce(child, pos-1, target);
-                }
-                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);
-            }
-        }
     }
 
-    private static final Forest[] emptyForestArray = new Forest[0];
-
-
     // Helpers //////////////////////////////////////////////////////////////////////////////
-
+    
+    private static void reachable(Sequence s, HashSet<Position> h) {
+        reachable(s.firstp(), h);
+        for(Sequence ss : s.needs()) reachable(ss, h);
+        for(Sequence ss : s.hates()) reachable(ss, h);
+    }
     private static void reachable(Element e, HashSet<Position> h) {
         if (e instanceof Atom) return;
         for(Sequence s : ((Union)e))
-            reachable(s.firstp(), h);
+            reachable(s, h);
     }
     private static void reachable(Position p, HashSet<Position> h) {
         if (h.contains(p)) return;