summaryrefslogtreecommitdiff
path: root/decoder/earley_composer.cc
blob: f6a01e520f20f5feab7ac68fd83fb56c99c31c1a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
#include "earley_composer.h"

#include <iostream>
#include <fstream>
#include <map>
#include <queue>
#include <tr1/unordered_set>

#include <boost/shared_ptr.hpp>
#include <boost/program_options.hpp>
#include <boost/program_options/variables_map.hpp>
#include <boost/lexical_cast.hpp>

#include "phrasetable_fst.h"
#include "sparse_vector.h"
#include "tdict.h"
#include "hg.h"

using boost::shared_ptr;
namespace po = boost::program_options;
using namespace std;
using namespace std::tr1;

// Define the following macro if you want to see lots of debugging output
// when you run the chart parser
#undef DEBUG_CHART_PARSER

// A few constants used by the chart parser ///////////////
static const int kMAX_NODES = 2000000;
static const string kPHRASE_STRING = "X";
static bool constants_need_init = true;
static WordID kUNIQUE_START;
static WordID kPHRASE;
static TRulePtr kX1X2;
static TRulePtr kX1;
static WordID kEPS;
static TRulePtr kEPSRule;

static void InitializeConstants() {
  if (constants_need_init) {
    kPHRASE = TD::Convert(kPHRASE_STRING) * -1;
    kUNIQUE_START = TD::Convert("S") * -1;
    kX1X2.reset(new TRule("[X] ||| [X,1] [X,2] ||| [X,1] [X,2]"));
    kX1.reset(new TRule("[X] ||| [X,1] ||| [X,1]"));
    kEPSRule.reset(new TRule("[X] ||| <eps> ||| <eps>"));
    kEPS = TD::Convert("<eps>");
    constants_need_init = false;
  }
}
////////////////////////////////////////////////////////////

class EGrammarNode {
  friend bool EarleyComposer::Compose(const Hypergraph& src_forest, Hypergraph* trg_forest);
  friend void AddGrammarRule(const string& r, map<WordID, EGrammarNode>* g);
 public:
#ifdef DEBUG_CHART_PARSER
  string hint;
#endif
  EGrammarNode() : is_some_rule_complete(false), is_root(false) {}
  const map<WordID, EGrammarNode>& GetTerminals() const { return tptr; }
  const map<WordID, EGrammarNode>& GetNonTerminals() const { return ntptr; }
  bool HasNonTerminals() const { return (!ntptr.empty()); }
  bool HasTerminals() const { return (!tptr.empty()); }
  bool RuleCompletes() const {
    return (is_some_rule_complete || (ntptr.empty() && tptr.empty()));
  }
  bool GrammarContinues() const {
    return !(ntptr.empty() && tptr.empty());
  }
  bool IsRoot() const {
    return is_root;
  }
  // these are the features associated with the rule from the start
  // node up to this point.  If you use these features, you must
  // not Extend() this rule.
  const SparseVector<double>& GetCFGProductionFeatures() const {
    return input_features;
  }

  const EGrammarNode* Extend(const WordID& t) const {
    if (t < 0) {
      map<WordID, EGrammarNode>::const_iterator it = ntptr.find(t);
      if (it == ntptr.end()) return NULL;
      return &it->second;
    } else {
      map<WordID, EGrammarNode>::const_iterator it = tptr.find(t);
      if (it == tptr.end()) return NULL;
      return &it->second;
    }
  }

 private:
  map<WordID, EGrammarNode> tptr;
  map<WordID, EGrammarNode> ntptr;
  SparseVector<double> input_features;
  bool is_some_rule_complete;
  bool is_root;
};
typedef map<WordID, EGrammarNode> EGrammar;    // indexed by the rule LHS

// edges are immutable once created
struct Edge {
#ifdef DEBUG_CHART_PARSER
  static int id_count;
  const int id;
#endif
  const WordID cat;                   // lhs side of rule proved/being proved
  const EGrammarNode* const dot;      // dot position
  const FSTNode* const q;             // start of span
  const FSTNode* const r;             // end of span
  const Edge* const active_parent;    // back pointer, NULL for PREDICT items
  const Edge* const passive_parent;   // back pointer, NULL for SCAN and PREDICT items
  const TargetPhraseSet* const tps;   // translations
  shared_ptr<SparseVector<double> > features; // features from CFG rule

  bool IsPassive() const {
    // when a rule is completed, this value will be set
    return static_cast<bool>(features);
  }
  bool IsActive() const { return !IsPassive(); }
  bool IsInitial() const {
    return !(active_parent || passive_parent);
  }
  bool IsCreatedByScan() const {
    return active_parent && !passive_parent && !dot->IsRoot();
  }
  bool IsCreatedByPredict() const {
    return dot->IsRoot();
  }
  bool IsCreatedByComplete() const {
    return active_parent && passive_parent;
  }

  // constructor for PREDICT
  Edge(WordID c, const EGrammarNode* d, const FSTNode* q_and_r) :
#ifdef DEBUG_CHART_PARSER
    id(++id_count),
#endif
    cat(c), dot(d), q(q_and_r), r(q_and_r), active_parent(NULL), passive_parent(NULL), tps(NULL) {}
  Edge(WordID c, const EGrammarNode* d, const FSTNode* q_and_r, const Edge* act_parent) :
#ifdef DEBUG_CHART_PARSER
    id(++id_count),
#endif
    cat(c), dot(d), q(q_and_r), r(q_and_r), active_parent(act_parent), passive_parent(NULL), tps(NULL) {}

  // constructors for SCAN
  Edge(WordID c, const EGrammarNode* d, const FSTNode* i, const FSTNode* j,
       const Edge* act_par, const TargetPhraseSet* translations) :
#ifdef DEBUG_CHART_PARSER
    id(++id_count),
#endif
    cat(c), dot(d), q(i), r(j), active_parent(act_par), passive_parent(NULL), tps(translations) {}

  Edge(WordID c, const EGrammarNode* d, const FSTNode* i, const FSTNode* j,
       const Edge* act_par, const TargetPhraseSet* translations,
       const SparseVector<double>& feats) :
#ifdef DEBUG_CHART_PARSER
    id(++id_count),
#endif
    cat(c), dot(d), q(i), r(j), active_parent(act_par), passive_parent(NULL), tps(translations),
    features(new SparseVector<double>(feats)) {}

  // constructors for COMPLETE
  Edge(WordID c, const EGrammarNode* d, const FSTNode* i, const FSTNode* j,
       const Edge* act_par, const Edge *pas_par) :
#ifdef DEBUG_CHART_PARSER
    id(++id_count),
#endif
    cat(c), dot(d), q(i), r(j), active_parent(act_par), passive_parent(pas_par), tps(NULL) {
      assert(pas_par->IsPassive());
      assert(act_par->IsActive());
    }

  Edge(WordID c, const EGrammarNode* d, const FSTNode* i, const FSTNode* j,
       const Edge* act_par, const Edge *pas_par, const SparseVector<double>& feats) :
#ifdef DEBUG_CHART_PARSER
    id(++id_count),
#endif
    cat(c), dot(d), q(i), r(j), active_parent(act_par), passive_parent(pas_par), tps(NULL),
    features(new SparseVector<double>(feats)) {
      assert(pas_par->IsPassive());
      assert(act_par->IsActive());
    }

  // constructor for COMPLETE query
  Edge(const FSTNode* _r) :
#ifdef DEBUG_CHART_PARSER
    id(0),
#endif
    cat(0), dot(NULL), q(NULL),
    r(_r), active_parent(NULL), passive_parent(NULL), tps(NULL) {}
  // constructor for MERGE quere
  Edge(const FSTNode* _q, int) :
#ifdef DEBUG_CHART_PARSER
    id(0),
#endif
    cat(0), dot(NULL), q(_q),
    r(NULL), active_parent(NULL), passive_parent(NULL), tps(NULL) {}
};
#ifdef DEBUG_CHART_PARSER
int Edge::id_count = 0;
#endif

ostream& operator<<(ostream& os, const Edge& e) {
  string type = "PREDICT";
  if (e.IsCreatedByScan())
    type = "SCAN";
  else if (e.IsCreatedByComplete())
    type = "COMPLETE"; 
  os << "["
#ifdef DEBUG_CHART_PARSER
     << '(' << e.id << ") "
#else
     << '(' << &e << ") "
#endif
     << "q=" << e.q << ", r=" << e.r 
     << ", cat="<< TD::Convert(e.cat*-1) << ", dot=" 
     << e.dot
#ifdef DEBUG_CHART_PARSER
     << e.dot->hint
#endif
     << (e.IsActive() ? ", Active" : ", Passive")
     << ", " << type;
#ifdef DEBUG_CHART_PARSER
  if (e.active_parent) { os << ", act.parent=(" << e.active_parent->id << ')'; }
  if (e.passive_parent) { os << ", psv.parent=(" << e.passive_parent->id << ')'; }
#endif
  if (e.tps) { os << ", tps=" << e.tps; }
  return os << ']';
}

struct Traversal {
  const Edge* const edge;      // result from the active / passive combination
  const Edge* const active;
  const Edge* const passive;
  Traversal(const Edge* me, const Edge* a, const Edge* p) : edge(me), active(a), passive(p) {}
};

struct UniqueTraversalHash {
  size_t operator()(const Traversal* t) const {
    size_t x = 5381;
    x = ((x << 5) + x) ^ reinterpret_cast<size_t>(t->active);
    x = ((x << 5) + x) ^ reinterpret_cast<size_t>(t->passive);
    x = ((x << 5) + x) ^ t->edge->IsActive();
    return x;
  }
};

struct UniqueTraversalEquals {
  size_t operator()(const Traversal* a, const Traversal* b) const {
    return (a->passive == b->passive && a->active == b->active && a->edge->IsActive() == b->edge->IsActive());
  }
};

struct UniqueEdgeHash {
  size_t operator()(const Edge* e) const {
    size_t x = 5381;
    if (e->IsActive()) {
      x = ((x << 5) + x) ^ reinterpret_cast<size_t>(e->dot);
      x = ((x << 5) + x) ^ reinterpret_cast<size_t>(e->q);
      x = ((x << 5) + x) ^ reinterpret_cast<size_t>(e->r);
      x = ((x << 5) + x) ^ static_cast<size_t>(e->cat);
      x += 13;
    } else {  // with passive edges, we don't care about the dot
      x = ((x << 5) + x) ^ reinterpret_cast<size_t>(e->q);
      x = ((x << 5) + x) ^ reinterpret_cast<size_t>(e->r);
      x = ((x << 5) + x) ^ static_cast<size_t>(e->cat);
    }
    return x;
  }
};

struct UniqueEdgeEquals {
  bool operator()(const Edge* a, const Edge* b) const {
    if (a->IsActive() != b->IsActive()) return false;
    if (a->IsActive()) {
      return (a->cat == b->cat) && (a->dot == b->dot) && (a->q == b->q) && (a->r == b->r);
    } else {
      return (a->cat == b->cat) && (a->q == b->q) && (a->r == b->r);
    }
  }
};

struct REdgeHash {
  size_t operator()(const Edge* e) const {
    size_t x = 5381;
    x = ((x << 5) + x) ^ reinterpret_cast<size_t>(e->r);
    return x;
  }
};

struct REdgeEquals {
  bool operator()(const Edge* a, const Edge* b) const {
    return (a->r == b->r);
  }
};

struct QEdgeHash {
  size_t operator()(const Edge* e) const {
    size_t x = 5381;
    x = ((x << 5) + x) ^ reinterpret_cast<size_t>(e->q);
    return x;
  }
};

struct QEdgeEquals {
  bool operator()(const Edge* a, const Edge* b) const {
    return (a->q == b->q);
  }
};

struct EdgeQueue {
  queue<const Edge*> q;
  EdgeQueue() {}
  void clear() { while(!q.empty()) q.pop(); }
  bool HasWork() const { return !q.empty(); }
  const Edge* Next() { const Edge* res = q.front(); q.pop(); return res; }
  void AddEdge(const Edge* s) { q.push(s); }
};

class EarleyComposerImpl {
 public:
  EarleyComposerImpl(WordID start_cat, const FSTNode& q_0) : start_cat_(start_cat), q_0_(&q_0) {}

  // returns false if the intersection is empty
  bool Compose(const EGrammar& g, Hypergraph* forest) {
    goal_node = NULL;
    EGrammar::const_iterator sit = g.find(start_cat_);
    forest->ReserveNodes(kMAX_NODES);
    assert(sit != g.end());
    Edge* init = new Edge(start_cat_, &sit->second, q_0_);
    assert(IncorporateNewEdge(init));
    while (exp_agenda.HasWork() || agenda.HasWork()) {
      while(exp_agenda.HasWork()) {
        const Edge* edge = exp_agenda.Next();
        FinishEdge(edge, forest);
      }
      if (agenda.HasWork()) {
        const Edge* edge = agenda.Next();
#ifdef DEBUG_CHART_PARSER
        cerr << "processing (" << edge->id << ')' << endl;
#endif
        if (edge->IsActive()) {
          if (edge->dot->HasTerminals())
            DoScan(edge);
          if (edge->dot->HasNonTerminals()) {
            DoMergeWithPassives(edge);
            DoPredict(edge, g);
          }
        } else {
          DoComplete(edge);
        }
      }
    }
    if (goal_node) {
      forest->PruneUnreachable(goal_node->id_);
      forest->EpsilonRemove(kEPS);
    }
    FreeAll();
    return goal_node;
  }

  void FreeAll() {
    for (int i = 0; i < free_list_.size(); ++i)
      delete free_list_[i];
    free_list_.clear();
    for (int i = 0; i < traversal_free_list_.size(); ++i)
      delete traversal_free_list_[i];
    traversal_free_list_.clear();
    all_traversals.clear();
    exp_agenda.clear();
    agenda.clear();
    tps2node.clear();
    edge2node.clear();
    all_edges.clear();
    passive_edges.clear();
    active_edges.clear();
  }

  ~EarleyComposerImpl() {
    FreeAll();
  }

  // returns the total number of edges created during composition
  int EdgesCreated() const {
    return free_list_.size();
  }

 private:
  void DoScan(const Edge* edge) {
    // here, we assume that the FST will potentially have many more outgoing
    // edges than the grammar, which will be just a couple.  If you want to
    // efficiently handle the case where both are relatively large, this code
    // will need to change how the intersection is done.  The best general
    // solution would probably be the Baeza-Yates double binary search.

    const EGrammarNode* dot = edge->dot;
    const FSTNode* r = edge->r;
    const map<WordID, EGrammarNode>& terms = dot->GetTerminals();
    for (map<WordID, EGrammarNode>::const_iterator git = terms.begin();
         git != terms.end(); ++git) {
      const FSTNode* next_r = r->Extend(git->first);
      if (!next_r) continue;
      const EGrammarNode* next_dot = &git->second;
      const bool grammar_continues = next_dot->GrammarContinues();
      const bool rule_completes    = next_dot->RuleCompletes();
      assert(grammar_continues || rule_completes);
      const SparseVector<double>& input_features = next_dot->GetCFGProductionFeatures();
      // create up to 4 new edges!
      if (next_r->HasOutgoingNonEpsilonEdges()) {     // are there further symbols in the FST?
        const TargetPhraseSet* translations = NULL;
        if (rule_completes)
          IncorporateNewEdge(new Edge(edge->cat, next_dot, edge->q, next_r, edge, translations, input_features));
        if (grammar_continues)
          IncorporateNewEdge(new Edge(edge->cat, next_dot, edge->q, next_r, edge, translations));
      }
      if (next_r->HasData()) {   // indicates a loop back to q_0 in the FST
        const TargetPhraseSet* translations = next_r->GetTranslations();
        if (rule_completes)
          IncorporateNewEdge(new Edge(edge->cat, next_dot, edge->q, q_0_, edge, translations, input_features));
        if (grammar_continues)
          IncorporateNewEdge(new Edge(edge->cat, next_dot, edge->q, q_0_, edge, translations));
      }
    }
  }

  void DoPredict(const Edge* edge, const EGrammar& g) {
    const EGrammarNode* dot = edge->dot;
    const map<WordID, EGrammarNode>& non_terms = dot->GetNonTerminals();
    for (map<WordID, EGrammarNode>::const_iterator git = non_terms.begin();
         git != non_terms.end(); ++git) {
      const WordID nt_to_predict = git->first;
      //cerr << edge->id << " -- " << TD::Convert(nt_to_predict*-1) << endl;
      EGrammar::const_iterator egi = g.find(nt_to_predict);
      if (egi == g.end()) {
        cerr << "[ERROR] Can't find any grammar rules with a LHS of type "
             << TD::Convert(-1*nt_to_predict) << '!' << endl;
        continue;
      }
      assert(edge->IsActive());
      const EGrammarNode* new_dot = &egi->second;
      Edge* new_edge = new Edge(nt_to_predict, new_dot, edge->r, edge);
      IncorporateNewEdge(new_edge);
    }
  }

  void DoComplete(const Edge* passive) {
#ifdef DEBUG_CHART_PARSER
    cerr << "  complete: " << *passive << endl;
#endif
    const WordID completed_nt = passive->cat;
    const FSTNode* q = passive->q;
    const FSTNode* next_r = passive->r;
    const Edge query(q);
    const pair<unordered_multiset<const Edge*, REdgeHash, REdgeEquals>::iterator,
         unordered_multiset<const Edge*, REdgeHash, REdgeEquals>::iterator > p =
      active_edges.equal_range(&query);
    for (unordered_multiset<const Edge*, REdgeHash, REdgeEquals>::iterator it = p.first;
         it != p.second; ++it) {
      const Edge* active = *it;
#ifdef DEBUG_CHART_PARSER
      cerr << "    pos: " << *active << endl;
#endif
      const EGrammarNode* next_dot = active->dot->Extend(completed_nt);
      if (!next_dot) continue;
      const SparseVector<double>& input_features = next_dot->GetCFGProductionFeatures();
      // add up to 2 rules
      if (next_dot->RuleCompletes())
        IncorporateNewEdge(new Edge(active->cat, next_dot, active->q, next_r, active, passive, input_features));
      if (next_dot->GrammarContinues())
        IncorporateNewEdge(new Edge(active->cat, next_dot, active->q, next_r, active, passive));
    }
  }

  void DoMergeWithPassives(const Edge* active) {
    // edge is active, has non-terminals, we need to find the passives that can extend it
    assert(active->IsActive());
    assert(active->dot->HasNonTerminals());
#ifdef DEBUG_CHART_PARSER
    cerr << "  merge active with passives: ACT=" << *active << endl;
#endif
    const Edge query(active->r, 1);
    const pair<unordered_multiset<const Edge*, QEdgeHash, QEdgeEquals>::iterator,
         unordered_multiset<const Edge*, QEdgeHash, QEdgeEquals>::iterator > p =
      passive_edges.equal_range(&query);
    for (unordered_multiset<const Edge*, QEdgeHash, QEdgeEquals>::iterator it = p.first;
         it != p.second; ++it) {
      const Edge* passive = *it;
      const EGrammarNode* next_dot = active->dot->Extend(passive->cat);
      if (!next_dot) continue;
      const FSTNode* next_r = passive->r;
      const SparseVector<double>& input_features = next_dot->GetCFGProductionFeatures();
      if (next_dot->RuleCompletes())
        IncorporateNewEdge(new Edge(active->cat, next_dot, active->q, next_r, active, passive, input_features));
      if (next_dot->GrammarContinues())
        IncorporateNewEdge(new Edge(active->cat, next_dot, active->q, next_r, active, passive));
    }
  }

  // take ownership of edge memory, add to various indexes, etc
  // returns true if this edge is new
  bool IncorporateNewEdge(Edge* edge) {
    free_list_.push_back(edge);
    if (edge->passive_parent && edge->active_parent) {
      Traversal* t = new Traversal(edge, edge->active_parent, edge->passive_parent);
      traversal_free_list_.push_back(t);
      if (all_traversals.find(t) != all_traversals.end()) {
        return false;
      } else {
        all_traversals.insert(t);
      }
    }
    exp_agenda.AddEdge(edge);
    return true;
  }

  bool FinishEdge(const Edge* edge, Hypergraph* hg) {
    bool is_new = false;
    if (all_edges.find(edge) == all_edges.end()) {
#ifdef DEBUG_CHART_PARSER
      cerr << *edge << " is NEW\n";
#endif
      all_edges.insert(edge);
      is_new = true;
      if (edge->IsPassive()) passive_edges.insert(edge);
      if (edge->IsActive()) active_edges.insert(edge);
      agenda.AddEdge(edge);
    } else {
#ifdef DEBUG_CHART_PARSER
      cerr << *edge << " is NOT NEW.\n";
#endif
    }
    AddEdgeToTranslationForest(edge, hg);
    return is_new;
  }

  // build the translation forest
  void AddEdgeToTranslationForest(const Edge* edge, Hypergraph* hg) {
    assert(hg->nodes_.size() < kMAX_NODES);
    Hypergraph::Node* tps = NULL;
    // first add any target language rules
    if (edge->tps) {
      Hypergraph::Node*& node = tps2node[(size_t)edge->tps];
      if (!node) {
        // cerr << "Creating phrases for " << edge->tps << endl;
        const vector<TRulePtr>& rules = edge->tps->GetRules();
        node = hg->AddNode(kPHRASE);
        for (int i = 0; i < rules.size(); ++i) {
          Hypergraph::Edge* hg_edge = hg->AddEdge(rules[i], Hypergraph::TailNodeVector());
          hg_edge->feature_values_ += rules[i]->GetFeatureValues();
          hg->ConnectEdgeToHeadNode(hg_edge, node);
        }
      }
      tps = node;
    }
    Hypergraph::Node*& head_node = edge2node[edge];
    if (!head_node)
      head_node = hg->AddNode(kPHRASE);
    if (edge->cat == start_cat_ && edge->q == q_0_ && edge->r == q_0_ && edge->IsPassive()) {
      assert(goal_node == NULL || goal_node == head_node);
      goal_node = head_node;
    }
    Hypergraph::TailNodeVector tail;
    SparseVector<double> extra;
    if (edge->IsCreatedByPredict()) {
      // extra.set_value(FD::Convert("predict"), 1);
    } else if (edge->IsCreatedByScan()) {
      tail.push_back(edge2node[edge->active_parent]->id_);
      if (tps) {
        tail.push_back(tps->id_);
      }
      //extra.set_value(FD::Convert("scan"), 1);
    } else if (edge->IsCreatedByComplete()) {
      tail.push_back(edge2node[edge->active_parent]->id_);
      tail.push_back(edge2node[edge->passive_parent]->id_);
      //extra.set_value(FD::Convert("complete"), 1);
    } else {
      assert(!"unexpected edge type!");
    }
    //cerr << head_node->id_ << "<--" << *edge << endl;

#ifdef DEBUG_CHART_PARSER
      for (int i = 0; i < tail.size(); ++i)
        if (tail[i] == head_node->id_) {
          cerr << "ERROR: " << *edge << "\n   i=" << i << endl;
          if (i == 1) { cerr << "\tP: " << *edge->passive_parent << endl; }
          if (i == 0) { cerr << "\tA: " << *edge->active_parent << endl; }
          assert(!"self-loop found!");
        }
#endif
    Hypergraph::Edge* hg_edge = NULL; 
    if (tail.size() == 0) {
      hg_edge = hg->AddEdge(kEPSRule, tail);
    } else if (tail.size() == 1) {
      hg_edge = hg->AddEdge(kX1, tail);
    } else if (tail.size() == 2) {
      hg_edge = hg->AddEdge(kX1X2, tail);
    }
    if (edge->features)
      hg_edge->feature_values_ += *edge->features;
    hg_edge->feature_values_ += extra;
    hg->ConnectEdgeToHeadNode(hg_edge, head_node);
  }

  Hypergraph::Node* goal_node;
  EdgeQueue exp_agenda;
  EdgeQueue agenda;
  unordered_map<size_t, Hypergraph::Node*> tps2node;
  unordered_map<const Edge*, Hypergraph::Node*, UniqueEdgeHash, UniqueEdgeEquals> edge2node;
  unordered_set<const Traversal*, UniqueTraversalHash, UniqueTraversalEquals> all_traversals;
  unordered_set<const Edge*, UniqueEdgeHash, UniqueEdgeEquals> all_edges;
  unordered_multiset<const Edge*, QEdgeHash, QEdgeEquals> passive_edges;
  unordered_multiset<const Edge*, REdgeHash, REdgeEquals> active_edges;
  vector<Edge*> free_list_;
  vector<Traversal*> traversal_free_list_;
  const WordID start_cat_;
  const FSTNode* const q_0_;
};

#ifdef DEBUG_CHART_PARSER
static string TrimRule(const string& r) {
  size_t start = r.find(" |||") + 5;
  size_t end = r.rfind(" |||");
  return r.substr(start, end - start);
}
#endif

void AddGrammarRule(const string& r, EGrammar* g) {
  const size_t pos = r.find(" ||| ");
  if (pos == string::npos || r[0] != '[') {
    cerr << "Bad rule: " << r << endl;
    return;
  }
  const size_t rpos = r.rfind(" ||| ");
  string feats;
  string rs = r;
  if (rpos != pos) {
    feats = r.substr(rpos + 5);
    rs = r.substr(0, rpos);
  }
  string rhs = rs.substr(pos + 5);
  string trule = rs + " ||| " + rhs + " ||| " + feats;
  TRule tr(trule);
#ifdef DEBUG_CHART_PARSER
  string hint_last_rule;
#endif
  EGrammarNode* cur = &(*g)[tr.GetLHS()];
  cur->is_root = true;
  for (int i = 0; i < tr.FLength(); ++i) {
    WordID sym = tr.f()[i];
#ifdef DEBUG_CHART_PARSER
    hint_last_rule = TD::Convert(sym < 0 ? -sym : sym);
    cur->hint += " <@@> (*" + hint_last_rule + ") " + TrimRule(tr.AsString());
#endif
    if (sym < 0)
      cur = &cur->ntptr[sym];
    else
      cur = &cur->tptr[sym];
  }
#ifdef DEBUG_CHART_PARSER
  cur->hint += " <@@> (" + hint_last_rule + "*) " + TrimRule(tr.AsString());
#endif
  cur->is_some_rule_complete = true;
  cur->input_features = tr.GetFeatureValues();
}

EarleyComposer::~EarleyComposer() {
  delete pimpl_;
}

EarleyComposer::EarleyComposer(const FSTNode* fst) {
  InitializeConstants();
  pimpl_ = new EarleyComposerImpl(kUNIQUE_START, *fst);
}

bool EarleyComposer::Compose(const Hypergraph& src_forest, Hypergraph* trg_forest) {
  // first, convert the src forest into an EGrammar
  EGrammar g;
  const int nedges = src_forest.edges_.size();
  const int nnodes = src_forest.nodes_.size();
  vector<int> cats(nnodes);
  bool assign_cats = false;
  for (int i = 0; i < nnodes; ++i)
    if (assign_cats) {
      cats[i] = TD::Convert("CAT_" + boost::lexical_cast<string>(i)) * -1;
    } else {
      cats[i] = src_forest.nodes_[i].cat_;
    }
  // construct the grammar
  for (int i = 0; i < nedges; ++i) {
    const Hypergraph::Edge& edge = src_forest.edges_[i];
    const vector<WordID>& src = edge.rule_->f();
    EGrammarNode* cur = &g[cats[edge.head_node_]];
    cur->is_root = true;
    int ntc = 0;
    for (int j = 0; j < src.size(); ++j) {
      WordID sym = src[j];
      if (sym <= 0) {
        sym = cats[edge.tail_nodes_[ntc]];
        ++ntc;
        cur = &cur->ntptr[sym];
      } else {
        cur = &cur->tptr[sym];
      }
    }
    cur->is_some_rule_complete = true;
    cur->input_features = edge.feature_values_;
  }
  EGrammarNode& goal_rule = g[kUNIQUE_START];
  assert((goal_rule.ntptr.size() == 1 && goal_rule.tptr.size() == 0) ||
         (goal_rule.ntptr.size() == 0 && goal_rule.tptr.size() == 1));

  return pimpl_->Compose(g, trg_forest);
}

bool EarleyComposer::Compose(istream* in, Hypergraph* trg_forest) {
  EGrammar g;
  while(*in) {
    string line;
    getline(*in, line);
    if (line.empty()) continue;
    AddGrammarRule(line, &g);
  }

  return pimpl_->Compose(g, trg_forest);
}