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Stanford Parser processes raw text in English, Chinese, German, Arabic, and French, and extracts constituency parse trees.
// Stanford Parser -- a probabilistic lexicalized NL CFG parser
// Copyright (c) 2002 - 2011 The Board of Trustees of
// The Leland Stanford Junior University. All Rights Reserved.
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//
// For more information, bug reports, fixes, contact:
// Christopher Manning
// Dept of Computer Science, Gates 1A
// Stanford CA 94305-9010
// USA
// [email protected]
// http://nlp.stanford.edu/software/lex-parser.shtml
package edu.stanford.nlp.parser.lexparser;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import edu.stanford.nlp.ling.CoreLabel;
import edu.stanford.nlp.ling.HasTag;
import edu.stanford.nlp.ling.HasWord;
import edu.stanford.nlp.ling.Label;
import edu.stanford.nlp.ling.Sentence;
import edu.stanford.nlp.ling.TaggedWord;
import edu.stanford.nlp.ling.Word;
import edu.stanford.nlp.parser.KBestViterbiParser;
import edu.stanford.nlp.parser.common.NoSuchParseException;
import edu.stanford.nlp.parser.common.ParserConstraint;
import edu.stanford.nlp.parser.common.ParserQuery;
import edu.stanford.nlp.trees.Tree;
import edu.stanford.nlp.trees.TreePrint;
import edu.stanford.nlp.trees.TreeTransformer;
import edu.stanford.nlp.trees.TreebankLanguagePack;
import edu.stanford.nlp.util.Generics;
import edu.stanford.nlp.util.Index;
import edu.stanford.nlp.util.ScoredObject;
import edu.stanford.nlp.util.DeltaIndex;
import edu.stanford.nlp.util.RuntimeInterruptedException;
public class LexicalizedParserQuery implements ParserQuery {
private final Options op;
private final TreeTransformer debinarizer;
private final TreeTransformer boundaryRemover;
/** The PCFG parser. */
private final ExhaustivePCFGParser pparser;
/** The dependency parser. */
private final ExhaustiveDependencyParser dparser;
/** The factored parser that combines the dependency and PCFG parsers. */
private final KBestViterbiParser bparser;
private final boolean fallbackToPCFG = true;
private final TreeTransformer subcategoryStripper;
// Whether or not the most complicated model available successfully
// parsed the input sentence.
private boolean parseSucceeded = false;
// parseSkipped means that not only did we not succeed at parsing,
// but for some reason we didn't even try. Most likely this happens
// when the sentence is too long or is of length 0.
private boolean parseSkipped = false;
// In some sense we succeeded, but only because we used a fallback grammar
private boolean parseFallback = false;
// Not enough memory to parse
private boolean parseNoMemory = false;
// Horrible error
private boolean parseUnparsable = false;
// If something ran out of memory, where the error occurred
private String whatFailed = null;
public boolean parseSucceeded() { return parseSucceeded; }
public boolean parseSkipped() { return parseSkipped; }
public boolean parseFallback() { return parseFallback; }
public boolean parseNoMemory() { return parseNoMemory; }
public boolean parseUnparsable() { return parseUnparsable; }
private List originalSentence;
@Override
public List originalSentence() { return originalSentence; }
/** Keeps track of whether the sentence had punctuation added, which affects the expected length of the sentence */
private boolean addedPunct = false;
private boolean saidMemMessage = false;
public boolean saidMemMessage() {
return saidMemMessage;
}
LexicalizedParserQuery(LexicalizedParser parser) {
this.op = parser.getOp();
BinaryGrammar bg = parser.bg;
UnaryGrammar ug = parser.ug;
Lexicon lex = parser.lex;
DependencyGrammar dg = parser.dg;
Index stateIndex = parser.stateIndex;
Index wordIndex = new DeltaIndex(parser.wordIndex);
Index tagIndex = parser.tagIndex;
this.debinarizer = new Debinarizer(op.forceCNF);
this.boundaryRemover = new BoundaryRemover();
if (op.doPCFG) {
if (op.testOptions.iterativeCKY) {
pparser = new IterativeCKYPCFGParser(bg, ug, lex, op, stateIndex, wordIndex, tagIndex);
} else {
pparser = new ExhaustivePCFGParser(bg, ug, lex, op, stateIndex, wordIndex, tagIndex);
}
} else {
pparser = null;
}
if (op.doDep) {
dg.setLexicon(lex);
if (!op.testOptions.useFastFactored) {
dparser = new ExhaustiveDependencyParser(dg, lex, op, wordIndex, tagIndex);
} else {
dparser = null;
}
} else {
dparser = null;
}
if (op.doDep && op.doPCFG) {
if (op.testOptions.useFastFactored) {
MLEDependencyGrammar mledg = (MLEDependencyGrammar) dg;
int numToFind = 1;
if (op.testOptions.printFactoredKGood > 0) {
numToFind = op.testOptions.printFactoredKGood;
}
bparser = new FastFactoredParser(pparser, mledg, op, numToFind, wordIndex, tagIndex);
} else {
Scorer scorer = new TwinScorer(pparser, dparser);
//Scorer scorer = parser;
if (op.testOptions.useN5) {
bparser = new BiLexPCFGParser.N5BiLexPCFGParser(scorer, pparser, dparser, bg, ug, dg, lex, op, stateIndex, wordIndex, tagIndex);
} else {
bparser = new BiLexPCFGParser(scorer, pparser, dparser, bg, ug, dg, lex, op, stateIndex, wordIndex, tagIndex);
}
}
} else {
bparser = null;
}
subcategoryStripper = op.tlpParams.subcategoryStripper();
}
@Override
public void setConstraints(List constraints) {
if (pparser != null) {
pparser.setConstraints(constraints);
}
}
/**
* Parse a sentence represented as a List of tokens.
* The text must already have been tokenized and
* normalized into tokens that are appropriate to the treebank
* which was used to train the parser. The tokens can be of
* multiple types, and the list items need not be homogeneous as to type
* (in particular, only some words might be given tags):
*
* - If a token implements HasWord, then the word to be parsed is
* given by its word() value.
* - If a token implements HasTag and the tag() value is not
* null or the empty String, then the parser is strongly advised to assign
* a part of speech tag that begins with this String.
*
*
* @param sentence The sentence to parse
* @return true Iff the sentence was accepted by the grammar
* @throws UnsupportedOperationException If the Sentence is too long or
* of zero length or the parse
* otherwise fails for resource reasons
*/
private boolean parseInternal(List sentence) {
parseSucceeded = false;
parseNoMemory = false;
parseUnparsable = false;
parseSkipped = false;
parseFallback = false;
whatFailed = null;
addedPunct = false;
originalSentence = sentence;
int length = sentence.size();
if (length == 0) {
parseSkipped = true;
throw new UnsupportedOperationException("Can't parse a zero-length sentence!");
}
List sentenceB;
if (op.wordFunction != null) {
sentenceB = Generics.newArrayList();
for (HasWord word : originalSentence) {
if (word instanceof Label) {
Label label = (Label) word;
Label newLabel = label.labelFactory().newLabel(label);
if (newLabel instanceof HasWord) {
sentenceB.add((HasWord) newLabel);
} else {
throw new AssertionError("This should have been a HasWord");
}
} else if (word instanceof HasTag) {
TaggedWord tw = new TaggedWord(word.word(), ((HasTag) word).tag());
sentenceB.add(tw);
} else {
sentenceB.add(new Word(word.word()));
}
}
for (HasWord word : sentenceB) {
word.setWord(op.wordFunction.apply(word.word()));
}
} else {
sentenceB = new ArrayList(sentence);
}
if (op.testOptions.addMissingFinalPunctuation) {
addedPunct = addSentenceFinalPunctIfNeeded(sentenceB, length);
}
if (length > op.testOptions.maxLength) {
parseSkipped = true;
throw new UnsupportedOperationException("Sentence too long: length " + length);
}
TreePrint treePrint = getTreePrint();
PrintWriter pwOut = op.tlpParams.pw();
//Insert the boundary symbol
if(sentence.get(0) instanceof CoreLabel) {
CoreLabel boundary = new CoreLabel();
boundary.setWord(Lexicon.BOUNDARY);
boundary.setValue(Lexicon.BOUNDARY);
boundary.setTag(Lexicon.BOUNDARY_TAG);
boundary.setIndex(sentence.size()+1);//1-based indexing used in the parser
sentenceB.add(boundary);
} else {
sentenceB.add(new TaggedWord(Lexicon.BOUNDARY, Lexicon.BOUNDARY_TAG));
}
if (Thread.interrupted()) {
throw new RuntimeInterruptedException();
}
if (op.doPCFG) {
if (!pparser.parse(sentenceB)) {
return parseSucceeded;
}
if (op.testOptions.verbose) {
pwOut.println("PParser output");
// getBestPCFGParse(false).pennPrint(pwOut); // with scores on nodes
treePrint.printTree(getBestPCFGParse(false), pwOut); // without scores on nodes
}
}
if (Thread.interrupted()) {
throw new RuntimeInterruptedException();
}
if (op.doDep && ! op.testOptions.useFastFactored) {
if ( ! dparser.parse(sentenceB)) {
return parseSucceeded;
}
// cdm nov 2006: should move these printing bits to the main printing section,
// so don't calculate the best parse twice!
if (op.testOptions.verbose) {
pwOut.println("DParser output");
treePrint.printTree(dparser.getBestParse(), pwOut);
}
}
if (Thread.interrupted()) {
throw new RuntimeInterruptedException();
}
if (op.doPCFG && op.doDep) {
if ( ! bparser.parse(sentenceB)) {
return parseSucceeded;
} else {
parseSucceeded = true;
}
}
return true;
}
@Override
public void restoreOriginalWords(Tree tree) {
if (originalSentence == null || tree == null) {
return;
}
List leaves = tree.getLeaves();
int expectedSize = addedPunct ? originalSentence.size() + 1 : originalSentence.size();
if (leaves.size() != expectedSize) {
throw new IllegalStateException("originalWords and sentence of different sizes: " + expectedSize + " vs. " + leaves.size() +
"\n Orig: " + Sentence.listToString(originalSentence) +
"\n Pars: " + Sentence.listToString(leaves));
}
Iterator leafIterator = leaves.iterator();
for (HasWord word : originalSentence) {
Tree leaf = leafIterator.next();
if (!(word instanceof Label)) {
continue;
}
leaf.setLabel((Label) word);
}
}
/**
* Parse a (speech) lattice with the PCFG parser.
*
* @param lr a lattice to parse
* @return Whether the lattice could be parsed by the grammar
*/
boolean parse(HTKLatticeReader lr) {
TreePrint treePrint = getTreePrint();
PrintWriter pwOut = op.tlpParams.pw();
parseSucceeded = false;
parseNoMemory = false;
parseUnparsable = false;
parseSkipped = false;
parseFallback = false;
whatFailed = null;
originalSentence = null;
if (lr.getNumStates() > op.testOptions.maxLength + 1) { // + 1 for boundary symbol
parseSkipped = true;
throw new UnsupportedOperationException("Lattice too big: " + lr.getNumStates());
}
if (op.doPCFG) {
if (!pparser.parse(lr)) {
return parseSucceeded;
}
if (op.testOptions.verbose) {
pwOut.println("PParser output");
treePrint.printTree(getBestPCFGParse(false), pwOut);
}
}
parseSucceeded = true;
return true;
}
/**
* Return the best parse of the sentence most recently parsed.
* This will be from the factored parser, if it was used and it succeeded
* else from the PCFG if it was used and succeed, else from the dependency
* parser.
*
* @return The best tree
* @throws NoSuchParseException If no previously successfully parsed
* sentence
*/
public Tree getBestParse() {
return getBestParse(true);
}
Tree getBestParse(boolean stripSubcat) {
if (parseSkipped) {
return null;
}
if (bparser != null && parseSucceeded) {
Tree binaryTree = bparser.getBestParse();
Tree tree = debinarizer.transformTree(binaryTree);
if (op.nodePrune) {
NodePruner np = new NodePruner(pparser, debinarizer);
tree = np.prune(tree);
}
if (stripSubcat) {
tree = subcategoryStripper.transformTree(tree);
}
restoreOriginalWords(tree);
return tree;
} else if (pparser != null && pparser.hasParse() && fallbackToPCFG) {
return getBestPCFGParse();
} else if (dparser != null && dparser.hasParse()) { // && fallbackToDG
// Should we strip subcategories like this? Traditionally haven't...
// return subcategoryStripper.transformTree(getBestDependencyParse(true));
return getBestDependencyParse(true);
} else {
throw new NoSuchParseException();
}
}
public List> getBestPCFGParses() {
return pparser.getBestParses();
}
public boolean hasFactoredParse() {
if (bparser == null) {
return false;
}
return !parseSkipped && parseSucceeded && bparser.hasParse();
}
public Tree getBestFactoredParse() {
return bparser.getBestParse();
}
public List> getKGoodFactoredParses(int k) {
if (bparser == null || parseSkipped) {
return null;
}
List> binaryTrees = bparser.getKGoodParses(k);
if (binaryTrees == null) {
return null;
}
List> trees = new ArrayList>(k);
for (ScoredObject tp : binaryTrees) {
Tree t = debinarizer.transformTree(tp.object());
t = subcategoryStripper.transformTree(t);
restoreOriginalWords(t);
trees.add(new ScoredObject(t, tp.score()));
}
return trees;
}
/**
* Returns the trees (and scores) corresponding to the
* k-best derivations of the sentence. This cannot be
* a Counter because frequently there will be multiple
* derivations which lead to the same parse tree.
*
* @param k The number of best parses to return
* @return The list of trees with their scores (log prob).
*/
public List> getKBestPCFGParses(int k) {
if (pparser == null) {
return null;
}
List> binaryTrees = pparser.getKBestParses(k);
if (binaryTrees == null) {
return null;
}
List> trees = new ArrayList>(k);
for (ScoredObject p : binaryTrees) {
Tree t = debinarizer.transformTree(p.object());
t = subcategoryStripper.transformTree(t);
restoreOriginalWords(t);
trees.add(new ScoredObject(t, p.score()));
}
return trees;
}
public Tree getBestPCFGParse() {
return getBestPCFGParse(true);
}
public Tree getBestPCFGParse(boolean stripSubcategories) {
if (pparser == null || parseSkipped || parseUnparsable) {
return null;
}
Tree binaryTree = pparser.getBestParse();
if (binaryTree == null) {
return null;
}
Tree t = debinarizer.transformTree(binaryTree);
if (stripSubcategories) {
t = subcategoryStripper.transformTree(t);
}
restoreOriginalWords(t);
return t;
}
@Override
public double getPCFGScore() {
return pparser.getBestScore();
}
double getPCFGScore(String goalStr) {
return pparser.getBestScore(goalStr);
}
void parsePCFG(List sentence) {
parseSucceeded = false;
parseNoMemory = false;
parseUnparsable = false;
parseSkipped = false;
parseFallback = false;
whatFailed = null;
originalSentence = sentence;
pparser.parse(sentence);
}
public Tree getBestDependencyParse() {
return getBestDependencyParse(false);
}
@Override
public Tree getBestDependencyParse(boolean debinarize) {
if (dparser == null || parseSkipped || parseUnparsable) {
return null;
}
Tree t = dparser.getBestParse();
if (t != null) {
if (debinarize) {
t = debinarizer.transformTree(t);
}
t = boundaryRemover.transformTree(t); // remove boundary .$$. which is otherwise still there from dparser.
restoreOriginalWords(t);
}
return t;
}
/**
* Parse a sentence represented as a List of tokens.
* The text must already have been tokenized and
* normalized into tokens that are appropriate to the treebank
* which was used to train the parser. The tokens can be of
* multiple types, and the list items need not be homogeneous as to type
* (in particular, only some words might be given tags):
*
* - If a token implements HasWord, then the word to be parsed is
* given by its word() value.
* - If a token implements HasTag and the tag() value is not
* null or the empty String, then the parser is strongly advised to assign
* a part of speech tag that begins with this String.
*
*
* @param sentence The sentence to parse
* @return true Iff the sentence was accepted by the grammar. If
* the main grammar fails, but the PCFG succeeds, then
* this still returns true, but parseFallback() will
* also return true. getBestParse() will have a valid
* result iff this returns true.
*/
@Override
public boolean parse(List sentence) {
try {
if (!parseInternal(sentence)) {
if (pparser != null && pparser.hasParse() && fallbackToPCFG) {
parseFallback = true;
return true;
} else {
parseUnparsable = true;
return false;
}
} else {
return true;
}
} catch (OutOfMemoryError e) {
if (op.testOptions.maxLength != -0xDEADBEEF) {
// this means they explicitly asked for a length they cannot handle.
// Throw exception. Avoid string concatenation before throw it.
System.err.print("NOT ENOUGH MEMORY TO PARSE SENTENCES OF LENGTH ");
System.err.println(op.testOptions.maxLength);
throw e;
}
if (pparser.hasParse() && fallbackToPCFG) {
try {
whatFailed = "dependency";
if (dparser.hasParse()) {
whatFailed = "factored";
}
parseFallback = true;
return true;
} catch (OutOfMemoryError oome) {
oome.printStackTrace();
parseNoMemory = true;
pparser.nudgeDownArraySize();
return false;
}
} else {
parseNoMemory = true;
return false;
}
} catch (UnsupportedOperationException uoe) {
parseSkipped = true;
return false;
}
}
/**
* Implements the same parsing with fallback that parse() does, but
* also outputs status messages for failed parses to pwErr.
*/
@Override
public boolean parseAndReport(List sentence, PrintWriter pwErr) {
boolean result = parse(sentence);
if (result) {
if (whatFailed != null) {
// Something failed, probably because of memory problems.
// However, we still got a PCFG parse, at least.
if ( ! saidMemMessage) {
ParserUtils.printOutOfMemory(pwErr);
saidMemMessage = true;
}
pwErr.println("Sentence too long for " + whatFailed + " parser. Falling back to PCFG parse...");
} else if (parseFallback) {
// We had to fall back for some other reason.
pwErr.println("Sentence couldn't be parsed by grammar.... falling back to PCFG parse.");
}
} else if (parseUnparsable) {
// No parse at all, completely failed.
pwErr.println("Sentence couldn't be parsed by grammar.");
} else if (parseNoMemory) {
// Ran out of memory, either with or without a possible PCFG parse.
if (!saidMemMessage) {
ParserUtils.printOutOfMemory(pwErr);
saidMemMessage = true;
}
if (pparser.hasParse() && fallbackToPCFG) {
pwErr.println("No memory to gather PCFG parse. Skipping...");
} else {
pwErr.println("Sentence has no parse using PCFG grammar (or no PCFG fallback). Skipping...");
}
} else if (parseSkipped) {
pwErr.println("Sentence too long (or zero words).");
}
return result;
}
/** Return a TreePrint for formatting parsed output trees.
* @return A TreePrint for formatting parsed output trees.
*/
public TreePrint getTreePrint() {
return op.testOptions.treePrint(op.tlpParams);
}
@Override
public KBestViterbiParser getPCFGParser() {
return pparser;
}
@Override
public KBestViterbiParser getDependencyParser() {
return dparser;
}
@Override
public KBestViterbiParser getFactoredParser() {
return bparser;
}
/** Adds a sentence final punctuation mark to sentences that lack one.
* This method adds a period (the first sentence final punctuation word
* in a parser language pack) to sentences that don't have one within
* the last 3 words (to allow for close parentheses, etc.). It checks
* tags for punctuation, if available, otherwise words.
*
* @param sentence The sentence to check
* @param length The length of the sentence (just to avoid recomputation)
*/
private boolean addSentenceFinalPunctIfNeeded(List sentence, int length) {
int start = length - 3;
if (start < 0) start = 0;
TreebankLanguagePack tlp = op.tlpParams.treebankLanguagePack();
for (int i = length - 1; i >= start; i--) {
HasWord item = sentence.get(i);
// An object (e.g., CoreLabel) can implement HasTag but not actually store
// a tag so we need to check that there is something there for this case.
// If there is, use only it, since word tokens can be ambiguous.
String tag = null;
if (item instanceof HasTag) {
tag = ((HasTag) item).tag();
}
if (tag != null && ! tag.isEmpty()) {
if (tlp.isSentenceFinalPunctuationTag(tag)) {
return false;
}
} else {
String str = item.word();
if (tlp.isPunctuationWord(str)) {
return false;
}
}
}
// none found so add one.
if (op.testOptions.verbose) {
System.err.println("Adding missing final punctuation to sentence.");
}
String[] sfpWords = tlp.sentenceFinalPunctuationWords();
if (sfpWords.length > 0) {
sentence.add(new Word(sfpWords[0]));
}
return true;
}
}