+// Copyright 2006 all rights reserved; see LICENSE file for BSD-style license
+
package edu.berkeley.sbp;
import edu.berkeley.sbp.*;
import edu.berkeley.sbp.util.*;
import java.io.*;
import java.util.*;
-/** a parser which translates streams of Tokens of type T into a Forest<R> */
-public abstract class Parser<Tok, Result> {
+/** a parser which translates an Input<Token> into a Forest<NodeType> */
+public abstract class Parser<Token, NodeType> {
- protected final Table<Tok> pt;
+ protected final Table<Token> pt;
/** create a parser to parse the grammar with start symbol <tt>u</tt> */
- protected Parser(Union u, Topology<Tok> top) { this.pt = new Table<Tok>(u, top); }
- protected Parser(Table<Tok> pt) { this.pt = pt; }
+ public Parser(Union u, Topology<Token> top) { this.pt = new Table<Token>(u, top); }
/** implement this method to create the output forest corresponding to a lone shifted input token */
- protected abstract Forest<Result> shiftToken(Tok t, Input.Location newloc);
-
- boolean helpgc = true;
+ public abstract Forest<NodeType> shiftToken(Token t, Input.Location newloc);
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(), loc, null);
- current.newNode(null, Forest.create(null, null, null, false), pt.start, true);
- int count = 1;
- 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(), 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;
+ private boolean verbose = false;;
+ private static final char[] spin = new char[] { '-', '\\', '|', '/' };
+ private int spinpos = 0;
+ private long last = 0;
+ void spin() {
+ if (verbose) {
+ long now = System.currentTimeMillis();
+ if (now-last < 70) return;
+ last = now;
+ System.err.print("\r " + spin[spinpos++ % (spin.length)]+"\r");
}
}
- // Table //////////////////////////////////////////////////////////////////////////////
-
- /** an SLR(1) parse table which may contain conflicts */
- 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");
+ /** parse <tt>input</tt>, and return the shared packed parse forest (or throw an exception) */
+ public Forest<NodeType> parse(Input<Token> input) throws IOException, ParseFailed {
+ verbose = System.getProperty("sbp.verbose", null) != null;
+ spinpos = 0;
+ try {
+ GSS gss = new GSS(input, this);
+ for(GSS.Phase current = gss.new Phase<Token>(pt.start); ;) {
+
+ if (verbose) {
+ String s;
+ s = " " + spin[spinpos++ % (spin.length)]+" parsing ";
+ s += input.getName();
+ s += " "+input.getLocation();
+ while(s.indexOf(':') != -1 && s.indexOf(':') < 8) s = " " + s;
+ String y = "@"+gss.viewPos+" ";
+ while(y.length() < 9) y = " " + y;
+ s += y;
+ //s += " doom="+Node.doomedNodes;
+ //while(s.length() < 40) s = s + " ";
+ s += " nodes="+gss.numOldNodes;
+ while(s.length() < 50) s = s + " ";
+ s += " shifted="+gss.numNewNodes;
+ while(s.length() < 60) s = s + " ";
+ s += " reductions="+gss.numReductions;
+ System.err.print("\r"+s+ANSI.clreol()+"\r");
}
- for(Topology<Tok> t : state.reductions)
- sb.append(" reduce \""+
- new edu.berkeley.sbp.chr.CharTopology((IntegerTopology<Character>)t)+"\" => " +
- state.reductions.getAll(t) + "\n");
+
+ // FIXME: make sure all the locations line up properly in here
+ if (current.isDone()) return (Forest<NodeType>)current.finalResult;
+ Forest forest = shiftToken((Token)current.token, input.getLocation());
+ current = gss.new Phase<Token>(current, forest);
}
- return sb.toString();
+ } finally {
+ if (verbose)
+ System.err.print("\r \r");
}
+ }
- 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);
- }
- }
+
+ // Table //////////////////////////////////////////////////////////////////////////////
+
+ /** an SLR(1) parse table which may contain conflicts */
+ static class Table<Token> extends Cache {
/** the start state */
- public final State<Tok> start;
+ public final State<Token> start;
+
+ /** the state from which no reductions can be done */
+ private final State<Token> 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>>();
+ HashSet<State<Token>> all_states = new HashSet<State<Token>>();
+ HashMap<HashSet<Position>,State<Token>> doomed_states = new HashMap<HashSet<Position>,State<Token>>();
+ HashMap<HashSet<Position>,State<Token>> normal_states = new HashMap<HashSet<Position>,State<Token>>();
/** 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) {
+ super(ux, top);
Union start0 = new Union("0");
- start0.add(new Sequence.Singleton(ux));
-
- for(Sequence s : start0) cache.eof.put(s, true);
- cache.eof.put(start0, true);
+ Sequence seq0 = new Sequence.Singleton(ux);
+ start0.add(seq0);
+ buildFollowSet(seq0, top, true);
// construct the set of states
- 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<Tok>(hp, all_states, all_elements);
+
+ this.dead_state = new State<Token>(new HashSet<Position>(), true);
+ this.start = new State<Token>(hp);
// for each state, fill in the corresponding "row" of the parse table
- for(State<Tok> state : all_states.values())
+ for(State<Token> state : all_states)
for(Position p : state.hs) {
// the Grammar's designated "last position" is the only accepting state
- if (start0.contains(p.owner()) && p.next()==null)
+ if (start0.contains(p.owner()) && p.next()==null && !state.doomed)
state.accept = true;
if (isRightNullable(p)) {
- Walk.Follow wf = new Walk.Follow(top.empty(), p.owner(), all_elements, cache);
- 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()));
+ Topology<Token> follow = (Topology<Token>)follow(p.owner());
+ for(Position p2 = p; p2 != null && p2.element() != null; p2 = p2.next()) {
+ if (!(p2.element() instanceof Union)) throw new Error("impossible");
+ Union u = (Union)p2.element();
+ Atom set = new edu.berkeley.sbp.chr.CharAtom(new edu.berkeley.sbp.chr.CharTopology((Topology<Character>)epsilonFollowSet(u)));
+ Element p2e = p2.element();
+ if (p2e instanceof Union)
+ for(Sequence p2es : ((Union)p2e))
+ follow = follow.intersect(follow(p2es));
+ if (set != null) follow = follow.intersect(set.getTokenTopology());
+ }
state.reductions.put(follow, p);
- if (wf.includesEof()) state.eofReductions.add(p);
+ if (followEof.contains(p.owner())) state.eofReductions.add(p);
}
// if the element following this position is an atom, copy the corresponding
// set of rows out of the "master" goto table and into this state's shift table
if (p.element() != null && p.element() instanceof Atom)
- state.shifts.addAll(state.gotoSetTerminals.subset(((Atom)p.element())));
+ state.shifts.addAll(state.gotoSetTerminals.subset(((Atom)p.element()).getTokenTopology()));
}
+
if (top instanceof IntegerTopology)
- for(State<Tok> state : all_states.values()) {
+ for(State<Token> state : all_states) {
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 (!possiblyEpsilon(p.element())) return false;
- return isRightNullable(p.next());
+ // crude algorithm to assing an ordinal ordering to every position
+ // al will be sorted in DECREASING order (al[0] >= al[1])
+ ArrayList<Sequence.Position> al = new ArrayList<Sequence.Position>();
+ for(State s : all_states) {
+ for(Object po : s) {
+ Sequence.Position p = (Sequence.Position)po;
+ if (al.contains(p)) continue;
+ int i=0;
+ for(; i<al.size(); i++) {
+ if (comparePositions(p, al.get(i)) < 0)
+ break;
+ }
+ al.add(i, p);
+ }
+ }
+ // FIXME: this actually pollutes the "pure" objects (the ones that should not be modified by the Parser)
+ // sort in increasing order...
+ OUTER: while(true) {
+ for(int i=0; i<al.size(); i++)
+ for(int j=i+1; j<al.size(); j++)
+ if (comparePositions(al.get(i), al.get(j)) > 0) {
+ Sequence.Position p = al.remove(j);
+ al.add(i, p);
+ continue OUTER;
+ }
+ break;
+ }
+
+ int j = 1;
+ int pk = 0;
+ for(int i=0; i<al.size(); i++) {
+ boolean inc = false;
+ for(int k=pk; k<i; k++) {
+ if (comparePositions(al.get(k), al.get(i)) > 0)
+ { inc = true; break; }
+ }
+ inc = true;
+ if (inc) {
+ j++;
+ pk = i;
+ }
+ al.get(i).ord = j;
+ }
+
+ /*
+ for(int i=0; i<al.size(); i++)
+ if (isRightNullable(al.get(i)))
+ System.out.println(al.get(i).ord + " " + al.get(i));
+ */
+ //mastercache = this;
}
/** a single state in the LR table and the transitions possible from it */
-
- class State<Tok> implements Comparable<State<Tok>>, IntegerMappable, Iterable<Position> {
+ class State<Token> implements IntegerMappable, Iterable<Position> {
public final int idx = master_state_idx++;
private final HashSet<Position> hs;
+ public HashSet<State<Token>> also = new HashSet<State<Token>>();
- public transient HashMap<Element,State<Tok>> gotoSetNonTerminals = new HashMap<Element,State<Tok>>();
- private transient TopologicalBag<Tok,State<Tok>> gotoSetTerminals = new TopologicalBag<Tok,State<Tok>>();
+ public transient HashMap<Sequence,State<Token>> gotoSetNonTerminals = new HashMap<Sequence,State<Token>>();
+ private transient TopologicalBag<Token,State<Token>> gotoSetTerminals = new TopologicalBag<Token,State<Token>>();
- 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 TopologicalBag<Token,Position> reductions = new TopologicalBag<Token,Position>();
+ private HashSet<Position> eofReductions = new HashSet<Position>();
+ private TopologicalBag<Token,State<Token>> shifts = new TopologicalBag<Token,State<Token>>();
+ private boolean accept = false;
- private VisitableMap<Tok,State<Tok>> oshifts = null;
- private VisitableMap<Tok,Position> oreductions = null;
+ private VisitableMap<Token,State<Token>> oshifts = null;
+ private VisitableMap<Token,Position> oreductions = null;
// Interface Methods //////////////////////////////////////////////////////////////////////////////
- boolean isAccepting() { return accept; }
- public Iterator<Position> iterator() { return hs.iterator(); }
-
- boolean canShift(Tok t) { return 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 isAccepting() { return accept; }
+ public Iterator<Position> iterator() { return hs.iterator(); }
+ boolean canShift(Token t) { return oshifts!=null && oshifts.contains(t); }
+ void invokeShifts(Token t, GSS.Phase phase, Result r) { oshifts.invoke(t, phase, r); }
+ boolean canReduce(Token t) {
+ return oreductions != null && (t==null ? eofReductions.size()>0 : oreductions.contains(t)); }
+ void invokeEpsilonReductions(Token t, Node node) {
+ if (t==null) for(Position r : eofReductions) node.invoke(r, null);
+ else oreductions.invoke(t, node, null);
}
-
- boolean canReduce(Tok t) { return 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);
+ void invokeReductions(Token t, Node node, Result b) {
+ //System.err.println("\rinvokage: " + this);
+ if (t==null) for(Position r : eofReductions) node.invoke(r, b);
+ else oreductions.invoke(t, node, b);
}
// Constructor //////////////////////////////////////////////////////////////////////////////
/**
* create a new state consisting of all the <tt>Position</tt>s in <tt>hs</tt>
* @param hs the set of <tt>Position</tt>s comprising this <tt>State</tt>
- * @param all_states the set of states already constructed (to avoid recreating states)
- * @param all_elements the set of all elements (Atom instances need not be included)
+ * @param all the set of all elements (Atom instances need not be included)
*
* In principle these two steps could be merged, but they
* are written separately to highlight these two facts:
* for non-Atom Elements.
* </ul>
*/
- public State(HashSet<Position> hs,
- HashMap<HashSet<Position>,State<Tok>> all_states,
- HashSet<Element> all_elements) {
+ public State(HashSet<Position> hs) { this(hs, false); }
+ public boolean doomed;
+ public State(HashSet<Position> hs, boolean doomed) {
this.hs = hs;
+ this.doomed = doomed;
// 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);
+ ((HashMap)(doomed ? doomed_states : normal_states)).put(hs, this);
+ ((HashSet)all_states).add(this);
+
+ for(Position p : hs) {
+ if (!p.isFirst()) continue;
+ for(Sequence s : p.owner().needs()) {
+ if (hs.contains(s.firstp())) continue;
+ HashSet<Position> h2 = new HashSet<Position>();
+ reachable(s, h2);
+ also.add(mkstate(h2, true));
+ }
+ for(Sequence s : p.owner().hates()) {
+ if (hs.contains(s.firstp())) continue;
+ HashSet<Position> h2 = new HashSet<Position>();
+ reachable(s, h2);
+ also.add(mkstate(h2, true));
+ }
+ }
// 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
// of _new_ positions (positions after shifting). These mappings are
// collectively known as the _closure_
- TopologicalBag<Tok,Position> bag0 = new TopologicalBag<Tok,Position>();
+ TopologicalBag<Token,Position> bag0 = new TopologicalBag<Token,Position>();
for(Position position : hs) {
if (position.isLast() || !(position.element() instanceof Atom)) continue;
Atom a = (Atom)position.element();
HashSet<Position> hp = new HashSet<Position>();
reachable(position.next(), hp);
- bag0.addAll(a, hp);
+ bag0.addAll(a.getTokenTopology(), hp);
}
// Step 1b: for each _minimal, contiguous_ set of characters having an identical next-position
// set, add that character set to the goto table (with the State corresponding to the
// computed next-position set).
- for(Topology<Tok> r : bag0) {
+ for(Topology<Token> 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<Tok>(h, all_states, all_elements) : all_states.get(h));
+ ((TopologicalBag)gotoSetTerminals).put(r, mkstate(h, doomed));
}
- // Step 2: for every non-Atom element (ie every Element which has a corresponding reduction),
- // compute the closure over every position in this set which is followed by a symbol
- // which could yield the Element in question.
+ // Step 2: for every Sequence, compute the closure over every position in this set which
+ // is followed by a symbol which could yield the Sequence.
//
// "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();
- if (e==null) continue;
- for(Element y : cache.ys.getAll(e)) {
- HashSet<Position> hp = new HashSet<Position>();
- reachable(p.next(), hp);
- move.addAll(y, hp);
- }
- }
- for(Element y : move) {
+
+ HashMapBag<Sequence,Position> move = new HashMapBag<Sequence,Position>();
+ for(Position p : hs)
+ if (!p.isLast() && p.element() instanceof Union)
+ for(Sequence s : ((Union)p.element())) {
+ HashSet<Position> hp = new HashSet<Position>();
+ reachable(p.next(), hp);
+ move.addAll(s, hp);
+ }
+ OUTER: for(Sequence y : move) {
+ // if a reduction is "lame", it should wind up in the dead_state after reducing
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);
+ State<Token> s = mkstate(h, doomed);
+ for(Position p : hs)
+ if (p.element() != null && (p.element() instanceof Union))
+ for(Sequence seq : ((Union)p.element()))
+ if (seq.needs.contains(y) || seq.hates.contains(y)) {
+ // FIXME: assumption that no sequence is ever both usefully (non-lamely) matched
+ // and also directly lamely matched
+ ((HashMap)gotoSetNonTerminals).put(y, dead_state);
+ continue OUTER;
+ }
gotoSetNonTerminals.put(y, s);
}
}
+ private State<Token> mkstate(HashSet<Position> h, boolean b) {
+ if (b) return doomed_states.get(h) == null ? (State)new State<Token>(h,b) : (State)doomed_states.get(h);
+ else return normal_states.get(h) == null ? (State)new State<Token>(h,b) : (State)normal_states.get(h);
+ }
+
public String toStringx() {
StringBuffer st = new StringBuffer();
for(Position p : this) {
}
return st.toString();
}
+
public String toString() {
StringBuffer ret = new StringBuffer();
ret.append("state["+idx+"]: ");
return ret.toString();
}
- public int compareTo(State<Tok> s) { return idx==s.idx ? 0 : idx < s.idx ? -1 : 1; }
public int toInt() { return idx; }
}
+
+ public String toString() {
+ StringBuffer sb = new StringBuffer();
+ sb.append("parse table");
+ for(State<Token> state : all_states) {
+ sb.append(" " + state + "\n");
+ for(Topology<Token> 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<Token> t : state.reductions)
+ sb.append(" reduce \""+
+ new edu.berkeley.sbp.chr.CharTopology((IntegerTopology<Character>)t)+"\" => " +
+ state.reductions.getAll(t) + "\n");
+ for(Sequence s : state.gotoSetNonTerminals.keySet())
+ sb.append(" goto "+state.gotoSetNonTerminals.get(s)+" from " + s + "\n");
+ }
+ return sb.toString();
+ }
}
// 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;
h.add(p);
if (p.element() != null) reachable(p.element(), h);
}
-
+ //public static Cache mastercache = null;
}
projects / sbp.git / blobdiff