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();
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;
+ count = next.size();
+ if (current.isDone()) return (Forest<R>)gss.finalResult;
current = next;
}
}
if (start0.contains(p.owner()) && p.next()==null)
state.accept = true;
- if (p.isRightNullable(cache)) {
+ 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());
- 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);
+ state.reductions.put(follow, p);
+ if (wf.includesEof()) state.eofReductions.add(p);
}
// if the element following this position is an atom, copy the corresponding
}
}
+ private boolean isRightNullable(Position p) {
+ if (p.isLast()) return true;
+ if (!p.element().possiblyEpsilon(this)) 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> {
- 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;
- 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>();
+ 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 //////////////////////////////////////////////////////////////////////////////
- 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 <B,C> void invokeShifts(Token t, Invokable<State,B,C> irbc, B b, C c) {
+ boolean canShift(Token t) { return oshifts.contains(t); }
+ <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);
+
+ boolean canReduce(Token t) { return t==null ? eofReductions.size()>0 : oreductions.contains(t); }
+ <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);
}
}
public String toString() {
- //return "state["+idx+"]";
StringBuffer ret = new StringBuffer();
ret.append("state["+idx+"]: ");
for(Position p : this) ret.append("{"+p+"} ");
}
public int compareTo(Table.State s) { return idx==s.idx ? 0 : idx < s.idx ? -1 : 1; }
- }
-
- /**
- * 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);
- }
+ public int toInt() { return idx; }
}
}
- 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))
projects / sbp.git / blobdiff