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<Result> shiftToken(Tok t, Input.Location loc);
+ protected abstract Forest<Result> shiftToken(Tok t, Input.Location newloc);
+
+ 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<Result> parse(Input<Tok> input) throws IOException, ParseFailed {
GSS gss = new GSS();
Input.Location loc = input.getLocation();
- GSS.Phase current = gss.new Phase<Tok>(null, this, null, input.next(1, 0, 0), loc, null);
- current.newNode(null, Forest.leaf(null, null), pt.start, true);
+ 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 : shiftToken((Tok)current.token, loc);
- GSS.Phase next = gss.new Phase<Tok>(current, this, current, input.next(count, gss.resets, gss.waits), loc, forest);
+ 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;
// Table //////////////////////////////////////////////////////////////////////////////
/** an SLR(1) parse table which may contain conflicts */
- public static class Table<Tok> extends Walk.Cache {
-
- public final Walk.Cache cache = this;
+ static class Table<Tok> extends Walk.Cache {
- public void optimize(Functor<Tok,Integer> f) {
+ public String toString() {
+ StringBuffer sb = new StringBuffer();
+ sb.append("parse table");
for(State<Tok> state : all_states.values()) {
- state.oreductions = state.reductions.optimize(f);
- state.oshifts = state.shifts.optimize(f);
+ 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;
+
private void walk(Element e, HashSet<Element> hs) {
if (e==null) return;
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<Tok> 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;
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);
cache.ys.addAll(e, new Walk.YieldSet(e, cache).walk());
HashSet<Position> hp = new HashSet<Position>();
reachable(start0, hp);
+
+ 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
if (p.element() != null && p.element() instanceof Atom)
state.shifts.addAll(state.gotoSetTerminals.subset(((Atom)p.element())));
}
+ 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<Tok> implements Comparable<State<Tok>>, 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;
// Interface Methods //////////////////////////////////////////////////////////////////////////////
- boolean isAccepting() { return accept; }
- public Iterator<Position> iterator() { return hs.iterator(); }
+ boolean isAccepting() { return accept; }
+ public Iterator<Position> iterator() { return hs.iterator(); }
- boolean canShift(Tok t) { return oshifts.contains(t); }
+ 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);
}
- boolean canReduce(Tok t) { return t==null ? eofReductions.size()>0 : oreductions.contains(t); }
+ 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);
// "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();
for(Element y : move) {
HashSet<Position> h = move.getAll(y);
State<Tok> s = all_states.get(h) == null ? new State<Tok>(h, all_states, all_elements) : all_states.get(h);
- gotoSetNonTerminals.put(y, s);
+ // 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() {
StringBuffer ret = new StringBuffer();
ret.append("state["+idx+"]: ");
// 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;
projects / sbp.git / blobdiff