//Tregex/Tsurgeon, InputPanel - a GUI for tree search and modification
//Copyright (c) 2007-2008 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.
//This code is a GUI interface to Tregex and Tsurgeon (which were
//written by Rogey Levy and Galen Andrew).
//For more information, bug reports, fixes, contact:
//Christopher Manning
//Dept of Computer Science, Gates 1A
//Stanford CA 94305-9010
//USA
// Support/Questions: parser-user@lists.stanford.edu
// Licensing: parser-support@lists.stanford.edu
//http://www-nlp.stanford.edu/software/tregex.shtml
package edu.stanford.nlp.trees.tregex.gui;
import edu.stanford.nlp.util.logging.Redwood;
import java.awt.Color;
import java.awt.ComponentOrientation;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import javax.swing.*;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;
import edu.stanford.nlp.trees.HeadFinder;
import edu.stanford.nlp.trees.Tree;
import edu.stanford.nlp.trees.TreeVisitor;
import edu.stanford.nlp.trees.tregex.TregexMatcher;
import edu.stanford.nlp.trees.tregex.TregexPattern;
import edu.stanford.nlp.trees.tregex.TregexPatternCompiler;
import edu.stanford.nlp.trees.tregex.tsurgeon.Tsurgeon;
import edu.stanford.nlp.trees.tregex.tsurgeon.TsurgeonPattern;
import edu.stanford.nlp.util.Generics;
/**
* Class representing the panel that gets input from the user and does (in a thread-safe manner)
* the computation for finding tree matches and performing tsurgeon operations. Also displays statistics.
*
* @author Anna Rafferty
*/
public class InputPanel extends JPanel implements ActionListener, ChangeListener {
/** A logger for this class */
private static Redwood.RedwoodChannels log = Redwood.channels(InputPanel.class);
private static final long serialVersionUID = -8219840036914495876L;
private static InputPanel inputPanel; // = null;
private JLabel foundStats;
private JButton findMatches;
private JButton cancel;
private JButton help;
private JTextArea tregexPattern;
private JComboBox<String> recentTregexPatterns;
private DefaultComboBoxModel<String> recentTregexPatternsModel;
private int numRecentPatterns = 5;// we save the last n patterns in our combo box, where n = numRecentPatterns
private JTextArea tsurgeonScript;
private TregexPatternCompiler compiler;//this should change only when someone changes the headfinder/basic category finder
private List<HistoryEntry> historyList;
private JFrame historyFrame; // = null;
private JLabel scriptLabel;
private boolean tsurgeonEnabled; // = false;
private JButton tsurgeonHelp;
private JButton cancelTsurgeon;
private Thread searchThread;
private JButton historyButton;
private JProgressBar progressBar;
private JButton browseButton;
private JFrame helpFrame;
private JFrame tsurgeonHelpFrame;
private JButton runScript;
public static synchronized InputPanel getInstance() {
if (inputPanel == null)
inputPanel = new InputPanel();
return inputPanel;
}
private InputPanel() {
//data stuff
compiler = new TregexPatternCompiler();
historyList = new ArrayList<>();
//layout/image stuff
this.setLayout(new GridBagLayout());
this.setBorder(BorderFactory.createTitledBorder(BorderFactory.createEmptyBorder(),"Search pattern: "));
//pattern/history area
JPanel tregexInput = makeTregexPatternArea();
//buttons
JPanel buttonBox = makeTregexButtonBox();
JPanel browseButtonBox = makeBrowseButtonBox();
//interactive (if set in prefs) tsurgeon pattern
Box tsurgeonBox = makeTSurgeonScriptArea();
//tsurgeon buttons
JPanel tsurgeonButtonBox = makeTSurgeonButtons();
//enable/disable tsurgeon by default
enableTsurgeonHelper(tsurgeonEnabled);//helper method used for initial call
//statistics/status
JPanel foundStatsBox = makeFoundStatsBox();
//put it together
JLabel bigEmptyLabel = new JLabel();
//bigEmptyLabel.setBorder(BorderFactory.createEtchedBorder());
GridBagConstraints c = new GridBagConstraints();
c.fill = GridBagConstraints.BOTH;
c.gridwidth = GridBagConstraints.REMAINDER;
c.weightx = 1.0;
c.weighty = 3.0/12;
c.gridx = 0;
c.gridy = 0;
this.add(tregexInput,c);
c.weighty = 1.0/12;
c.gridy = 1;
this.add(buttonBox,c);
c.weighty = 1.0/12;
c.gridy = 2;
this.add(browseButtonBox,c);
c.weighty = 0.5/12;
c.gridy = 3;
this.add(bigEmptyLabel,c);
c.weighty = 3.0/12;
c.gridy = 4;
c.anchor = GridBagConstraints.SOUTH;
this.add(tsurgeonBox,c);
c.weighty = 1.0/12;
c.gridy = 5;
//c.gridheight = GridBagConstraints.REMAINDER;
c.anchor = GridBagConstraints.SOUTH;
this.add(tsurgeonButtonBox,c);
c.gridheight = GridBagConstraints.REMAINDER;
c.weighty = 1.0/12;
c.gridy = 6;
this.add(foundStatsBox, c);
}
//separated out to make constructor more readable
private JPanel makeFoundStatsBox() {
JPanel foundStatsBox = new JPanel();
foundStatsBox.setLayout(new GridBagLayout());
Box labelBox = Box.createHorizontalBox();
foundStats = new JLabel(" ");
labelBox.add(foundStats);
historyButton = new JButton("Statistics");
historyButton.setEnabled(false);
historyButton.addActionListener(this);
GridBagConstraints c = new GridBagConstraints();
c.fill = GridBagConstraints.BOTH;
c.weightx = 1.7;
foundStatsBox.add(labelBox,c);
c.weightx = .3;
c.gridwidth = 1;
foundStatsBox.add(historyButton);
return foundStatsBox;
}
//separated out to make constructor more readable
private JPanel makeTSurgeonButtons() {
JPanel tsurgeonButtonBox = new JPanel();
tsurgeonButtonBox.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
tsurgeonButtonBox.setLayout(new GridBagLayout());
tsurgeonHelp = new JButton("Help");
tsurgeonHelp.addActionListener(this);
cancelTsurgeon = new JButton("Cancel");
cancelTsurgeon.addActionListener(this);
runScript = new JButton("Run script");
runScript.addActionListener(this);
//make constraints and add in
GridBagConstraints c = new GridBagConstraints();
c.anchor = GridBagConstraints.NORTHEAST;
c.fill = GridBagConstraints.HORIZONTAL;
tsurgeonButtonBox.add(runScript,c);
tsurgeonButtonBox.add(cancelTsurgeon,c);
tsurgeonButtonBox.add(tsurgeonHelp,c);
c.gridwidth = GridBagConstraints.REMAINDER;
c.weightx = 1.0;
c.weighty = 1.0;
tsurgeonButtonBox.add(new JLabel(), c);
return tsurgeonButtonBox;
}
//separated out to make constructor more readable
private Box makeTSurgeonScriptArea() {
Box tsurgeonBox = Box.createHorizontalBox();
scriptLabel = new JLabel("Tsurgeon script: ");
tsurgeonScript = new JTextArea();
tsurgeonScript.setBorder(BorderFactory.createEmptyBorder());
tsurgeonScript.setFocusTraversalKeysEnabled(true);
JScrollPane scriptScroller = new JScrollPane(tsurgeonScript);
scriptScroller.setBorder(BorderFactory.createBevelBorder(javax.swing.border.BevelBorder.LOWERED));
//scriptScroller.setEnabled(tsurgeonEnabled);
tsurgeonBox.add(scriptLabel);
tsurgeonBox.add(scriptScroller);
//tsurgeonBox.setBorder(BorderFactory.createEtchedBorder());
return tsurgeonBox;
}
//separated out to make constructor more readable
private JPanel makeTregexPatternArea() {
//combo box with recent searches
recentTregexPatternsModel = new DefaultComboBoxModel<>();
recentTregexPatterns = new JComboBox<>(recentTregexPatternsModel);
recentTregexPatterns.setMinimumSize(new Dimension(120, 24));
recentTregexPatterns.addActionListener(this);
JLabel recentLabel = new JLabel("Recent: ");
//interactive tregex pattern
JLabel patternLabel = new JLabel("Pattern: ");
tregexPattern = new JTextArea();
tregexPattern.setFocusTraversalKeysEnabled(true);
tregexPattern.setLineWrap(true);
JScrollPane patternScroller = new JScrollPane(tregexPattern);
patternScroller.setBorder(BorderFactory.createBevelBorder(javax.swing.border.BevelBorder.LOWERED));
//add them into the panel
JPanel tregexInput = new JPanel();
tregexInput.setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
c.fill = GridBagConstraints.BOTH;
c.weightx = 1.0;
c.weighty = 1.0;
c.gridx = 0;
c.gridy = 0;
tregexInput.add(recentLabel, c);
c.weightx = 12.0;
c.gridwidth = GridBagConstraints.REMAINDER;
c.gridx = 1;
tregexInput.add(recentTregexPatterns, c);
c.weightx = 1.0;
c.gridwidth = 1; //reset to default
c.gridheight = GridBagConstraints.REMAINDER;
c.gridx = 0;
c.gridy = 1;
tregexInput.add(patternLabel,c);
c.gridx = 1;
c.weightx = 12.0;
c.weighty = 2.0;
c.gridwidth = GridBagConstraints.REMAINDER;
tregexInput.add(patternScroller,c);
//tregexInput.setBorder(BorderFactory.createEtchedBorder());
return tregexInput;
}
//separated out to make constructor more readable
private JPanel makeTregexButtonBox() {
JPanel buttonBox = new JPanel();
buttonBox.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
buttonBox.setLayout(new GridBagLayout());
//buttonBox.setBorder(BorderFactory.createEtchedBorder());
help = new JButton("Help");
help.addActionListener(this);
cancel = new JButton("Cancel");
cancel.setEnabled(false);
cancel.addActionListener(this);
findMatches = new JButton("Search");
findMatches.addActionListener(this);
// browseButton = new JButton("Browse Trees");
// browseButton.addActionListener(this);
JLabel emptyLabel = new JLabel();
// JLabel emptyLabel2 = new JLabel();
GridBagConstraints buttonConstraints = new GridBagConstraints();
buttonConstraints.fill = GridBagConstraints.HORIZONTAL;
buttonBox.add(findMatches,buttonConstraints);
buttonBox.add(cancel,buttonConstraints);
buttonBox.add(help,buttonConstraints);
buttonConstraints.gridwidth = GridBagConstraints.REMAINDER;
buttonConstraints.weightx = 1.0;
buttonConstraints.weighty = 1.0;
buttonBox.add(emptyLabel, buttonConstraints);
// buttonConstraints.gridwidth = 1;
// buttonBox.add(browseButton, buttonConstraints);
// buttonConstraints.gridwidth = GridBagConstraints.REMAINDER;
// buttonBox.add(emptyLabel2, buttonConstraints);
return buttonBox;
}
private JPanel makeBrowseButtonBox() {
JPanel buttonBox = new JPanel();
buttonBox.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
buttonBox.setLayout(new GridBagLayout());
browseButton = new JButton("Browse Trees");
browseButton.addActionListener(this);
JLabel sizeLabel = new JLabel("Tree size:");
JSlider fontSlider = new JSlider(2, 64, 12);
fontSlider.addChangeListener(this);
GridBagConstraints buttonConstraints = new GridBagConstraints();
buttonConstraints.fill = GridBagConstraints.HORIZONTAL;
buttonConstraints.weightx = 0.2;
buttonConstraints.weighty = 0.2;
buttonBox.add(browseButton,buttonConstraints);
buttonConstraints.weightx = 0.6;
buttonBox.add(fontSlider, buttonConstraints);
buttonConstraints.weightx = 0.2;
buttonBox.add(sizeLabel, buttonConstraints);
return buttonBox;
}
public void enableTsurgeon(boolean enable) {
if(tsurgeonEnabled == enable)
return;//nothing changes
enableTsurgeonHelper(enable);
}
//Doesn't check if tsurgeon is already in this enable state - used by enableTsurgeon and for
//initially enabling/disabling tsurgeon.
private void enableTsurgeonHelper(boolean enable) {
scriptLabel.setEnabled(enable);
tsurgeonScript.setEnabled(enable);
tsurgeonHelp.setEnabled(enable);
cancelTsurgeon.setEnabled(false);//should always be off unless we're running a script
runScript.setEnabled(enable);
tsurgeonEnabled = enable;
TregexGUI.getInstance().setTsurgeonEnabled(enable);
}
public List<HistoryEntry> getHistoryList() {
return historyList;
}
public String getHistoryString() {
StringBuilder sb = new StringBuilder();
sb.append(HistoryEntry.header());
sb.append('\n');
for(HistoryEntry e : this.getHistoryList()) {
sb.append(e.toString());
sb.append('\n');
}
return sb.toString();
}
private void addToHistoryList(String pattern, int numTreesMatched, int numMatches) {
if(!historyButton.isEnabled()) {
historyButton.setEnabled(true);
TregexGUI.getInstance().setSaveHistoryEnabled(true);
}
historyList.add(new HistoryEntry(pattern, numTreesMatched, numMatches));
}
public void setHeadFinder(HeadFinder hf) {
compiler = new TregexPatternCompiler(hf);
}
/**
* Updates the number of unique trees matched and the number of total trees matched by the last
* pattern that was searched for. Thread-safe.
*
* @param pattern The pattern
* @param treeMatches count of unique trees matched by the pattern
* @param totalMatches count of total matching instances
*/
public void updateFoundStats(final String pattern, final int treeMatches, final int totalMatches) {
final String txt = "<html>Match stats: " + treeMatches + " unique trees found with " + totalMatches + " total matches.</html>";
SwingUtilities.invokeLater(() -> {
foundStats.setPreferredSize(foundStats.getSize());
foundStats.setText(txt);
if(pattern != null)
addToHistoryList(pattern, treeMatches, totalMatches);
});
}
public void useProgressBar(boolean useProgressBar) {
if (useProgressBar) {//make sure we're in progress bar mode
if (progressBar == null) {
progressBar = new JProgressBar(JProgressBar.HORIZONTAL);
Container dad = foundStats.getParent();
useProgressBarHelper(dad, progressBar, foundStats);
}
} else {//make sure we're in found stats mode
if (progressBar != null) {
Container dad = progressBar.getParent();
useProgressBarHelper(dad, foundStats, progressBar);
progressBar = null;
}
}
}
private static void useProgressBarHelper(Container parent, JComponent add, JComponent remove) {
GridBagConstraints c = new GridBagConstraints();
c.fill = GridBagConstraints.BOTH;
c.weightx = 1.7;
parent.remove(remove);
parent.add(add,c);
parent.validate();
parent.repaint();
}
@Override
public void actionPerformed(ActionEvent e) {
Object source = e.getSource();
if (source == findMatches) {
runSearch();
} else if (source == cancel) {
if (searchThread != null) {
searchThread.interrupt();
}
cancel.setEnabled(false);
} else if (source == help) {
displayHelp();
} else if (source == tsurgeonHelp) {
displayTsurgeonHelp();
} else if (source == cancelTsurgeon) {
if (searchThread != null) {
searchThread.interrupt();
}
cancelTsurgeon.setEnabled(false);
} else if (source == runScript) {
runScript();
} else if (source == recentTregexPatterns) {
doRecent();
} else if (source == historyButton) {
showHistory();
} else if (source == browseButton) {
runBrowse();
}
}
@Override
public void stateChanged(ChangeEvent e) {
JSlider source = (JSlider) e.getSource();
int fontSize = source.getValue();
if ( ! source.getValueIsAdjusting()) {
DisplayMatchesPanel.getInstance().setFontSizeRepaint(fontSize);
}
}
private static class TregexGUITableModel extends DefaultTableModel {
private static final long serialVersionUID = -8095682087502853273L;
TregexGUITableModel(Object[][] entries, String[] columnNames) {
super(entries, columnNames);
}
@Override
public boolean isCellEditable(int row, int column) {
return false;
}
}
private void showHistory() {
if (historyFrame == null) {
historyFrame = new JFrame("Statistics History");
} else {
historyFrame.setVisible(false);
historyFrame= new JFrame("Statistics History");
}
historyFrame.setLayout(new GridLayout(1,0));
Object[][] entries = new Object[historyList.size()][3];
for(int i = 0; i < historyList.size(); i++) {
entries[i] = historyList.get(i).toArray();
}
DefaultTableModel tableModel = new TregexGUITableModel(entries, HistoryEntry.columnNamesArray());
JTable statTable = new JTable(tableModel);
DefaultTableCellRenderer dtcr = (DefaultTableCellRenderer) statTable.getDefaultRenderer(String.class);
dtcr.setHorizontalAlignment(DefaultTableCellRenderer.CENTER);
JScrollPane scroller = new JScrollPane(statTable);
historyFrame.add(scroller);
historyFrame.pack();
historyFrame.setLocationRelativeTo(TregexGUI.getInstance());
historyFrame.setBackground(Color.WHITE);
historyFrame.setVisible(true);
historyFrame.repaint();
}
private void doRecent() {
//this is called only when a user does something
Object recent = recentTregexPatternsModel.getSelectedItem();
if (recent != null) {
String selected = recent.toString();
if (selected.length() != 0) {
tregexPattern.setText(selected);
}
}
}
private void runBrowse() {
this.setPreferredSize(this.getSize());
Thread browseThread = new Thread() {
@Override
public void run() {
useProgressBar(true);
final List<TreeFromFile> trees = new ArrayList<>();
//Go through the treebanks and get all the trees
List<FileTreeNode> treebanks = FilePanel.getInstance().getActiveTreebanks();
//Tdiff
if(TregexGUI.getInstance().isTdiffEnabled())
treebanks.remove(0); //Remove the reference
double multiplier = 100.0/treebanks.size();
for (int i = 0; i < treebanks.size(); i++) {
FileTreeNode treebank = treebanks.get(i);
String filename = treebank.getFilename();
for (Tree curTree : treebank.getTreebank()) {
trees.add(new TreeFromFile(curTree, filename));
}
updateProgressBar(multiplier*(i+1));
}
SwingUtilities.invokeLater(() -> {
MatchesPanel.getInstance().setMatches(trees, null);
MatchesPanel.getInstance().focusOnList();
useProgressBar(false);
});//end SwingUtilities.invokeLater
} //end run
};//end Thread
browseThread.start();
}
void runSearch() {
setTregexState(true);
MatchesPanel.getInstance().removeAllMatches();
this.setPreferredSize(this.getSize());
searchThread = new Thread() {
@Override
public void run() {
final String text = tregexPattern.getText().intern();
SwingUtilities.invokeLater(() -> {
InputPanel.this.addRecentTregexPattern(text);
useProgressBar(true);
});
final TRegexGUITreeVisitor visitor = getMatchTreeVisitor(text,this);
if (visitor != null) {
SwingUtilities.invokeLater(() -> {
useProgressBar(false);
updateFoundStats(text, visitor.getMatches().size(), visitor.numUniqueMatches());
//addToHistoryList(text, visitor.getMatches().size(), visitor.numUniqueMatches());
MatchesPanel.getInstance().setMatches(visitor.getMatches(), visitor.getMatchedParts());
MatchesPanel.getInstance().focusOnList();
});
}
SwingUtilities.invokeLater(() -> {
setTregexState(false);
InputPanel.this.searchThread = null;
});
}
};
searchThread.start();
}
private void setTregexState(boolean running) {
cancel.setEnabled(running);
findMatches.setEnabled(!running);
browseButton.setEnabled(!running);
}
//Assumes that it will be called only if Tsurgeon is already enabled
private void setTsurgeonState(boolean running) {
cancelTsurgeon.setEnabled(running);
runScript.setEnabled(!running);
findMatches.setEnabled(!running);
browseButton.setEnabled(!running);
}
private void runScript() {
setTsurgeonState(true);
final String script = tsurgeonScript.getText();
searchThread = new Thread() {
@Override
public void run() {
try {
BufferedReader reader = new BufferedReader(new StringReader(script));
TsurgeonPattern operation = Tsurgeon.getTsurgeonOperationsFromReader(reader);
final String text = tregexPattern.getText().intern();
SwingUtilities.invokeLater(() -> {
InputPanel.this.addRecentTregexPattern(text);
useProgressBar(true);
});
final TRegexGUITreeVisitor visitor = getMatchTreeVisitor(text,this);
if (visitor == null) return; //means the tregex errored out
if (this.isInterrupted()) {
returnToValidState(text, visitor, new ArrayList<>());
return;
}
//log.info("Running Script with matches: " + visitor.getMatches());
List<TreeFromFile> trees = visitor.getMatches();
final List<TreeFromFile> modifiedTrees = new ArrayList<>();
for (TreeFromFile tff : trees) {
if (this.isInterrupted()) {
returnToValidState(text, visitor, trees);
return;
}
Tree modifiedTree = Tsurgeon.processPattern(visitor.getPattern(), operation, tff.getTree());
modifiedTrees.add(new TreeFromFile(modifiedTree,tff.getFilename().intern()));
}
returnToValidState(text, visitor, modifiedTrees);
} catch (Exception e) {
doError("Sorry, there was an error compiling or running the Tsurgeon script. Please press Help if you need assistance.", e);
SwingUtilities.invokeLater(() -> {
setTregexState(false);
setTsurgeonState(false);
InputPanel.this.searchThread = null;
});
}
}
};
searchThread.start();
}
private void returnToValidState(final String pattern, final TRegexGUITreeVisitor visitor, final List<TreeFromFile> trees) {
SwingUtilities.invokeLater(() -> {
int numUniqueMatches = 0;
if (trees.size() > 0) {
numUniqueMatches = visitor.numUniqueMatches();
}
updateFoundStats(pattern, trees.size(), numUniqueMatches);
MatchesPanel.getInstance().setMatches(trees, visitor.getMatchedParts());
useProgressBar(false);
setTsurgeonState(false);
});
}
public void setScriptAndPattern(String tregexPatternString, String tsurgeonScriptString) {
this.tregexPattern.setText(tregexPatternString);
this.tsurgeonScript.setText(tsurgeonScriptString);
}
private void addRecentTregexPattern(String pattern) {
// If pattern already exists, just move it to the top of the list
int existingIndex = recentTregexPatternsModel.getIndexOf(pattern);
if (existingIndex != -1) {
recentTregexPatternsModel.removeElementAt(existingIndex);
recentTregexPatternsModel.insertElementAt(pattern, 0);
recentTregexPatterns.setSelectedIndex(0);
return;
}
if(recentTregexPatternsModel.getSize() >= numRecentPatterns) {
recentTregexPatternsModel.removeElementAt(numRecentPatterns - 1);
}
recentTregexPatternsModel.insertElementAt(pattern,0);
recentTregexPatterns.setSelectedIndex(0);
recentTregexPatterns.revalidate();
}
public void setNumRecentPatterns(int n) {
numRecentPatterns = n;
//shrink down the number of recent patterns if necessary
while(recentTregexPatternsModel.getSize() > n) {
int lastIndex = recentTregexPatternsModel.getSize() - 1;
recentTregexPatternsModel.removeElementAt(lastIndex);
}
}
/**
* Check all active treebanks to find the trees that match the given pattern when interpreted
* as a tregex pattern.
*
* @param patternString string version of the tregex pattern you wish to match
* @param t The thread we are running on
* @return tree visitor that contains the trees that were matched as well as the parts of those trees that matched
*/
private TRegexGUITreeVisitor getMatchTreeVisitor(String patternString, Thread t) {
TRegexGUITreeVisitor vis = null;
try {
TregexPattern pattern = compiler.compile(patternString);
vis = new TRegexGUITreeVisitor(pattern); //handles);
List<FileTreeNode> treebanks = FilePanel.getInstance().getActiveTreebanks();
double multiplier = 100.0/treebanks.size();
int treebankNum = 1;
for (FileTreeNode treebank : treebanks) {
if (t.isInterrupted()) { //get out as quickly as possible if interrupted
t.interrupt();
// cdm 2008: I added here resetting the buttons or else it didn't seem to happen; not quite sure this is the right place to do it but.
SwingUtilities.invokeLater(() -> {
setTregexState(false);
InputPanel.this.searchThread = null;
});
return vis;
}
vis.setFilename(treebank.getFilename().intern());
treebank.getTreebank().apply(vis);
updateProgressBar(multiplier*treebankNum++);
}
} catch (OutOfMemoryError oome) {
vis = null;
doError("Sorry, search aborted as out of memory.\nTry either running Tregex with more memory or sticking to searches that don't produce thousands of matches.", oome);
} catch (Exception e) {
doError("Sorry, there was an error compiling or running the Tregex pattern. Please press Help if you need assistance.", e);
}
return vis;
}
/**
* Called when a pattern cannot be compiled or some other error occurs; resets gui to valid state.
* Thread safe.
*
* @param txt Error message text (friendly text appropriate for users)
* @param e The exception that caused the problem
*/
public void doError(final String txt, final Throwable e) {
SwingUtilities.invokeLater(() -> {
String extraData = e.getLocalizedMessage() != null ? e.getLocalizedMessage(): (e.getClass() != null) ? e.getClass().toString(): "";
JOptionPane.showMessageDialog(InputPanel.this, txt + '\n' + extraData, "Tregex Error", JOptionPane.ERROR_MESSAGE);
e.printStackTrace(); // send to stderr for debugging
useProgressBar(false);
updateFoundStats(null, 0, 0);
});
}
/**
* Thread safe way to update how much progress we've made on the search so far
* @param progress Percentage of the way through that we are.
*/
public void updateProgressBar(final double progress) {
if(progressBar == null)
return;
SwingUtilities.invokeLater(() -> progressBar.setValue((int) progress));
}
/**
* Simple class for storing history objects that go nicely into a toString for saving
* @author rafferty
*
*/
public static class HistoryEntry {
private final String pattern;
private final int numTreesMatched;
private final int numMatches;
public HistoryEntry(String pattern, int numTreesMatched, int numMatches) {
this.pattern = pattern;
this.numTreesMatched = numTreesMatched;
this.numMatches = numMatches;
}
/**
* Returns an array with pattern as the first entry, numTreesMatched as the second, and numMatches as the third
* @return An array with pattern as the first entry, numTreesMatched as the second, and numMatches as the third
*/
public Object[] toArray() {
Object[] array = new Object[3];
array[0] = pattern;
array[1] = numTreesMatched;
array[2] = numMatches;
return array;
}
public static String[] columnNamesArray() {
String[] names = {"Pattern","Trees Matched", "Total Matches"};
return names;
}
@Override
public String toString() {
return pattern + '\t' + numTreesMatched + '\t' + numMatches + '\t';
}
/**
* Gets the string header indicating the fields included in a HistoryEntry string representation
* @return A String header
*/
public static String header() {
return "pattern\tnumTreesMatched\tnumMatches";
}
} // end class HistoryEntry
public static class TRegexGUITreeVisitor implements TreeVisitor {
private int totalMatches; // = 0;
private final TregexPattern p;
private final List<TreeFromFile> matchedTrees;
private final Map<TreeFromFile,List<Tree>> matchedParts;
private String filename = "";
TRegexGUITreeVisitor(TregexPattern p) { //String[] handles) {
this.p = p;
//this.handles = handles;
matchedTrees = new ArrayList<>();
matchedParts = Generics.newHashMap();
}
public Map<TreeFromFile,List<Tree>> getMatchedParts() {
return matchedParts;
}
public void visitTree(Tree t) {
int numMatches = 0;
TregexMatcher match = p.matcher(t);
List<Tree> matchedPartList = null; // initialize lazily, since usually most trees don't match!
while (match.find()) {
Tree curMatch = match.getMatch();
//System.out.println("Found match is: " + curMatch);
if (matchedPartList == null) matchedPartList = new ArrayList<>();
matchedPartList.add(curMatch);
numMatches++;
} // end while match.find()
if(numMatches > 0) {
TreeFromFile tff = new TreeFromFile(t, filename);
matchedTrees.add(tff);
matchedParts.put(tff,matchedPartList);
totalMatches += numMatches;
}
} // end visitTree
/**
* Method for returning the number of matches found in the last tree
* visited by this tree visitor.
* @return number of matches found in previous tree
*/
public int numUniqueMatches() {
return totalMatches;
}
public List<TreeFromFile> getMatches() {
return matchedTrees;
}
public String getFilename() {
return filename;
}
public void setFilename(String curFilename) {
this.filename = curFilename.intern();
}
public TregexPattern getPattern() {
return p;
}
} // end class TRegexTreeVisitor
private void displayHelp() {
if (helpFrame != null) {
helpFrame.setVisible(true);
} else {
helpFrame = new JFrame("Tregex Help...");
//JPanel helpPanel = new JPanel();
JEditorPane helpText = new JEditorPane();
helpText.setContentType("text/html");
// StringBuffer s = new StringBuffer();
// s.append(htmlHelp);
helpText.setText(htmlHelp);
helpText.setEditable(false);
//helpPanel.add(helpText);
JScrollPane scroller = new JScrollPane(helpText);
helpText.setCaretPosition(0);
scroller.setPreferredSize(new Dimension(500,500));
helpFrame.add(scroller);
helpFrame.pack();
helpFrame.setBackground(Color.WHITE);
helpFrame.setVisible(true);
//helpFrame.repaint();
}
}
private void displayTsurgeonHelp() {
if(tsurgeonHelpFrame != null) {
tsurgeonHelpFrame.setVisible(true);
} else {
tsurgeonHelpFrame = new JFrame("TSurgeon Help...");
JEditorPane helpText = new JEditorPane();
helpText.setContentType("text/html");
// StringBuffer s = new StringBuffer();
// s.append(htmlTsurgeonHelp);
helpText.setText(htmlTsurgeonHelp);
helpText.setEditable(false);
JScrollPane scroller = new JScrollPane(helpText);
helpText.setCaretPosition(0);
scroller.setPreferredSize(new Dimension(500,500));
tsurgeonHelpFrame.add(scroller);
tsurgeonHelpFrame.pack();
tsurgeonHelpFrame.setBackground(Color.WHITE);
tsurgeonHelpFrame.setVisible(true);
}
}
//help text for tsurgeon is basically just the javadoc main comment for tsurgeon
private static final String htmlTsurgeonHelp = ( "<html><body>" +
"<h1>Tsurgeon Script Syntax and Uses</h1><p>Tsurgeon is a tool that can modify the trees found by Tregex searches. " +
" These modifications are specified via a script language, and the script language allows one to, among other" +
" operations, rename, delete, move, and insert nodes in a tree. " +
" For example, if you want to excise an SBARQ node whenever it is the parent of an SQ node, and rename the SQ node " +
" to S, your input would look like this:" +
"<p>" +
"Tregex pattern: " +
" <blockquote>" +
" <code>" +
" SBARQ=n1 < SQ=n2<br></code>" +
" <br>" +
" </blockquote>" +
"TSurgeon script: " +
" <blockquote>" +
"<code>" +
" excise n1 n1 <br>" +
" relabel n2 S" +
" </code>" +
" </blockquote>" +
" <h2>Legal operation syntax:</h2>" +
" <dl>" +
" <dt><code>delete <name>+</code></dt> <dd>Deletes one or more nodes and everything below them, with names that were given in the TregexPattern (e.g., VP=x).</dd>" +
" <dt><code>prune <name>+</code></dt> <dd>Like delete, but if, after the pruning, the parent has no children anymore, the parent is pruned too.</dd>" +
" <dt><code>excise <name1> <name2></code></dt>" +
" <dd>The name1 node should either dominate or be the same as the name2 node. This excises out everything from" +
" name1 to name2 inclusive. All the children of name2 go into the parent of name1, where name1 was.</dd>" +
" <dt><code>relabel <name> <new-label></code></dt> <dd>Relabels the node to have the new label." +
" There are three possible forms: <code>relabel nodeX VP</code> - for changing a node label to an alphanumeric string, " +
" <code>relabel nodeX /''/</code> - for relabeling a node to something that isn't a valid identifier without quoting, and " +
" <code>relabel nodeX /^VB(.*)$/verb\\/$1/</code> - for regular expression based relabeling. In the last case, all matches " +
" of the regular expression against the node label are replaced with the replacement String. This has the semantics of" +
" Java/Perl's replaceAll: you may use capturing groups and put them in replacements with $n. Also, as in the example, " +
" you can escape a slash in the middle of the second and third forms with \\/ and \\\\.</dd>" +
" <dt><code>insert <name> <position></code></dt>" +
" <dt><code>insert <tree> <position></code></dt><dd>Inserts the named node or tree into the position specified. (giving a tree rather than a node is also valid)</dd>" +
" <dt><code>move <name> <position></code></dt> <dd>moves the named node into the specified position</dd>" +
" <dd><dl><dt>Right now the only ways to specify position are:</dt> " ) +
" <dd><code>$+ <name></code> the left sister of the named node</dd>" +
" <dd><code>$- <name></code> the right sister of the named node</dd>" +
" <dd><code>>i</code> the <i>i</i><sup>th</sup> daughter of the named node</dd>" +
" <dd><code>>-i</code> the <i>i</i><sup>th</sup> daughter, counting from the right, of the named node.</dd></dl></dd>" +
" <dt><code>replace <name1> <tree></code></dt>" +
" <dt><code>replace <name1> <name2></code></dt> <dd>deletes name1 and inserts a tree or a copy of name2 in its place.</dd>" +
" <dt><code>createSubtree <auxiliary-tree-or-label> <name1> [<name2>]</code></dt> <dd>Create a subtree out of all the nodes from <code><name1></code> through <code><name2></code>.The subtree is moved to the foot of the given auxiliary tree, and the tree is inserted where the nodes of the subtree used to reside. If a simple label is provided as the first argument, the subtree is given a single parent with a name corresponding to the label. To limit the operation to just one node, elide <code><name2></code>.</dd>" +
" <dt><code>adjoin <auxiliary_tree> <name></code></dt> <dd>Adjoins the specified auxiliary tree into the named node. The daughters of the target node will become the daughters of the foot of the auxiliary tree. (The node <code>name</code> is no longer accessible.)</dd>" +
" <dt><code>adjoinH <auxiliary_tree> <name></code></dt> <dd>Similar to adjoin, but preserves the target node and makes it the root of <tree>. (It is still accessible as <code>name</code>. The root of the auxiliary tree is ignored.)</dd>" +
" <dt><code>adjoinF <auxiliary_tree> <name></code></dt> <dd> Similar to adjoin, but preserves the target node and makes it the foot of <tree>." +
" (It is still accessible as <code>name</code>, and retains its status as parent of its children. The foot of the auxiliary tree is ignored.)</dd>" +
" <dt><code>coindex <name1> <name2> ... <nameM> </code></dt> <dd>Puts a (Penn Treebank style) coindexation suffix of the form \"-N\" on" +
" each of nodes name_1 through name_m. The value of N will be "+
" automatically generated in reference to the existing coindexations " +
" in the tree, so that there is never an accidental clash of " +
" indices across things that are not meant to be coindexed.</dd>"+
" </dl> " +
"<h2>Syntax for trees to be inserted or adjoined:</h2>" +
"A tree to be adjoined in can be specified with LISP-like " +
"parenthetical-bracketing tree syntax such as those used for the Penn " +
"Treebank. For example, for the NP \"the dog\" to be inserted you might " +
"use the syntax" +
"<br>" +
" <blockquote>" +
" <code>" +
"(NP (Det the) (N dog))" +
" </code>" +
"</blockquote>" +
"<br>" +
"That's all that is necessary for a tree to be inserted. Auxiliary trees " +
"(a la Tree Adjoining Grammar) must also have exactly one frontier node " +
"ending in the character \"@\", which marks it as the \"foot\" node for " +
"adjunction. Final instances of the character \"@\" in terminal node labels " +
"will be removed from the actual label of the tree. " +
"<p>" +
"For example, if you wanted to adjoin the adverb \"breathlessly\" into a " +
"VP, you might specify the following auxiliary tree: " +
"<br>" +
" <blockquote>" +
" <code>" +
"(VP (Adv breathlessly VP@ )" +
" </code>" +
"</blockquote>" +
"<br>" +
"All other instances of \"@\" in terminal nodes must be escaped (i.e., " +
"appear as \\@); this escaping will be removed by tsurgeon. " +
"<p>" +
"In addition, any node of a tree can be named (the same way as in " +
"tregex), by appending =<name> to the node label. That name can be " +
"referred to by subsequent Tsurgeon operations triggered by the same " +
"match. All other instances of \"=\" in node labels must be escaped " +
"(i.e., appear as \\=); this escaping will be removed by Tsurgeon. For " +
"example, if you want to insert an NP trace somewhere and coindex it " +
"with a node named \"antecedent\" you might say: " +
"<br>" +
" <blockquote>" +
" <code>" +
"insert (NP (-NONE- *T*=trace)) <node-location>" +
"<br>"+
"coindex trace antecedent $ " +
" </blockquote>" +
" </code>" +
"<h2>Tips and Tricks</h2>" +
"<ol>" +
"<li>Be aware of how insert and replace work: Both of these operations look for matches again " +
"after being applied. This can cause infinite loops if your Tregex pattern continues to match the same " +
"configuration regardless of how many times you insert your tree. To avoid this, write Tregex patterns " +
"that match before but not after an insert or move is applied. For example, you could specify that the node " +
"not have an NP right sister in the Tregex match if your insert involved inserting an NP as the right sister " +
"of the node.</li>" +
"<li>Use the cancel button when necessary: If you do end up writing an operation that might have cycles and " +
"the Tregex GUI seems to be stuck in an infinite loop, press Cancel to stop the operation and recheck your Tregex pattern " +
"and Tsurgeon commands.</li>" +
"<li>Read the README: Three README files were included with this package - README-tregex.txt, README-tsurgeon.txt, " +
"and README-gui.txt. The Tsurgeon README includes examples of each operation as well as notes on the specifics of " +
"writing each type of operation.</li>" +
"</ol></body></html>";
//help text is basically just the javadoc main comment for TregexPattern
private static final String htmlHelp = ( "<html><h1>Tregex Pattern Syntax and Uses</h1><p>" +
" Tregex is a program for finding syntactic trees of interest in a collection of parsed sentences " +
" (a treebank). For matching, it uses a pattern language for specifying partial syntactic tree configurations. " +
" For example, the pattern <code>VP < VBD</code> matches verb phrases headed" +
" by a past tense verb. " +
" Using a Tregex pattern, you can find only those trees that match the pattern you're " +
" looking for. To get started, you first use the <code>File</code> menu to load a treebank of parsed trees " +
" (not supplied with Tregex) and then you enter a pattern and press <code>Search</code>. " +
" If your Treebank is not in UTF-8/ASCII or not in Penn Treebank format, you should" +
" also specify the treebank format and encoding under the <code>Preferences</code> menu item <i>before</i> loading the treebank. " +
" <p>" +
" The following table shows the symbols that are allowed in the pattern," +
" and below there is more information about using these patterns." +
"<p> <table border = \"1\"> <tr><th>Symbol<th>Meaning " +
" <tr><td>A << B <td>A dominates B" +
" <tr><td>A >> B <td>A is dominated by B" +
" <tr><td>A < B <td>A immediately dominates B" +
" <tr><td>A > B <td>A is immediately dominated by B" +
" <tr><td>A $ B <td>A is a sister of B (and not equal to B)" +
" <tr><td>A .. B <td>A precedes B" +
"<tr><td>A . B <td>A immediately precedes B" +
"<tr><td>A ,, B <td>A follows B" +
"<tr><td>A , B <td>A immediately follows B" +
"<tr><td>A <<, B <td>B is a leftmost descendant of A" +
"<tr><td>A <<- B <td>B is a rightmost descendant of A" +
"<tr><td>A >>, B <td>A is a leftmost descendant of B" +
"<tr><td>A >>- B <td>A is a rightmost descendant of B" +
"<tr><td>A <, B <td>B is the first child of A" +
"<tr><td>A >, B <td>A is the first child of B" +
"<tr><td>A <- B <td>B is the last child of A" +
"<tr><td>A >- B <td>A is the last child of B" +
"<tr><td>A <` B <td>B is the last child of A" +
"<tr><td>A >` B <td>A is the last child of B" +
"<tr><td>A <i B <td>B is the ith child of A (i > 0)" +
"<tr><td>A >i B <td>A is the ith child of B (i > 0)" +
"<tr><td>A <-i B <td>B is the ith-to-last child of A (i > 0)" +
"<tr><td>A >-i B <td>A is the ith-to-last child of B (i > 0)" +
"<tr><td>A <: B <td>B is the only child of A" +
"<tr><td>A >: B <td>A is the only child of B" +
"<tr><td>A <<: B <td>A dominates B via an unbroken chain (length > 0) of unary local trees." +
"<tr><td>A >>: B <td>A is dominated by B via an unbroken chain (length > 0) of unary local trees." +
"<tr><td>A $++ B <td>A is a left sister of B (same as $.. for context-free trees)" +
"<tr><td>A $-- B <td>A is a right sister of B (same as $,, for context-free trees)" +
"<tr><td>A $+ B <td>A is the immediate left sister of B (same as $. for context-free trees)" +
"<tr><td>A $- B <td>A is the immediate right sister of B (same as $, for context-free trees)" +
"<tr><td>A $.. B <td>A is a sister of B and precedes B" +
"<tr><td>A $,, B <td>A is a sister of B and follows B" +
"<tr><td>A $. B <td>A is a sister of B and immediately precedes B" +
"<tr><td>A $, B <td>A is a sister of B and immediately follows B" +
"<tr><td>A <+(C) B <td>A dominates B via an unbroken chain of (zero or more) nodes matching description C" +
"<tr><td>A >+(C) B <td>A is dominated by B via an unbroken chain of (zero or more) nodes matching description C" +
"<tr><td>A .+(C) B <td>A precedes B via an unbroken chain of (zero or more) nodes matching description C" +
"<tr><td>A ,+(C) B <td>A follows B via an unbroken chain of (zero or more) nodes matching description C" +
"<tr><td>A <<# B <td>B is a head of phrase A" +
"<tr><td>A >># B <td>A is a head of phrase B" +
"<tr><td>A <# B <td>B is the immediate head of phrase A" +
"<tr><td>A ># B <td>A is the immediate head of phrase B" +
"<tr><td>A == B <td>A and B are the same node" +
"<tr><td>A : B<td>[this is a pattern-segmenting operator that places no constraints on the relationship between A and B]" +
"</table>") +
(" <p> Node label descriptions (represented by A, B, and C in the table above) " +
" match either internal nodes or words in a sentence. They can be plain strings, which much match labels" +
" exactly, or regular expressions in regular expression slashes: /regex/." +
" Literal string matching proceeds as String equality."+
" In order to prevent ambiguity with other Tregex symbols, there are some restrictions " +
" on characters in plain strings: you can use standard" +
" \"identifiers\" - i.e., strings matching [a-zA-Z]([a-zA-Z0-9_])* - " +
" or any non-ASCII character, such as Arabic or Chinese letters." +
" If you want to use other symbols, you can do so by using a regular " +
" expression instead of a string, for example /^,$/ for a comma. " +
" Note that strings only match a complete node label, while regular expressions match " +
" if they match anywhere inside the node label. " +
" A disjunctive list of literal strings can be given separated by '|'." +
" The special string '__' (two underscores) can be used to match any" +
" node. (WARNING!! Use of the '__' node description may seriously" +
" slow down search.) If a label description is preceded by '@', the" +
" label will match any node whose <em>basicCategory</em> matches the" +
" description. <em>NB: A single '@' thus scopes over a disjunction" +
" specified by '|': @NP|VP means things with basic category NP or VP." +
" </em> Label description regular expressions are matched as a Java regex" +
" <code>find()</code>, as in Perl/tgrep;" +
" you need to specify <code>^</code> or <code>$</code> to constrain matches" +
" to the ends of node labels." +
" <p> " +
" In a chain of relations, all relations are relative to the first node in " +
" the chain. Nodes can be grouped using parentheses '(' and ')' to change this. " +
" For example, <code> (S < VP < NP) </code> means" +
" \"an S over a VP and also over an NP\"." +
" If instead what you want is an S above a VP above an NP, you should write" +
" \"<code>S < (VP < NP)</code>\"." +
" The expression <code> S < (NP $++ VP) </code> matches an S" +
" over an NP, where the NP has a VP as a right sister.") +
(" <p><h3>Boolean relational operators</h3>" +
" Relations can be combined using the '&' and '|' operators," +
" negated with the '!' operator, and made optional with the '?' operator. Thus" +
" <code> (NP < NN | < NNS) </code> will match an NP node dominating either" +
" an NN or an NNS. <code> (NP > S & $++ VP) </code> matches an NP that" +
" is both under an S and has a VP as a right sister." +
" <p> Relations can be grouped using brackets '[' and ']'. So the" +
" expression" +
" <blockquote>" +
" <code> NP [< NN | < NNS] & > S </code>" +
" </blockquote>" +
" matches an NP that (1) dominates either an NN or an NNS, and (2) is under an S. Without" +
" brackets, & takes precidence over |, and equivalent operators are" +
" left-associative. Also note that & is the default combining operator if the" +
" operator is omitted in a chain of relations, so that these two patterns are equivalent:" +
" <blockquote>" +
" <code> (S < VP < NP) </code><br>" +
" <code> (S < VP & < NP) </code>" +
" </blockquote>" +
" As another example, <code> (VP < VV | < NP $ NP)" +
" </code> can be written explicitly as <code> (VP [< VV | [< NP & $ NP] ] )" +
" </code>." +
" <p> Relations can be negated with the '!' operator, in which case the" +
" expression will match only if there is no node satisfying the relation." +
" For example <code> (NP !< NNP) </code> matches only NPs not dominating" +
" an NNP. Label descriptions can also be negated with '!': (NP < !NNP|NNS) matches" +
" NPs dominating some node that is not an NNP or an NNS." +
" <p> Relations can be made optional with the '?' operator. This way the" +
" expression will match even if the optional relation is not satisfied. This is useful when used together" +
" with node naming (see below).") +
" <p><h3>Basic Categories</h3>" +
" In order to consider only the \"basic category\" of a tree label," +
" i.e., to ignore functional tags or other annotations on the label," +
" prefix that node's description with the @ symbol. For example" +
" <code> (@NP < @/NN.?/) </code>. By default, the notion of basic category" +
" works for Penn Treebank tree node labels. This can only be used for individual nodes;" +
" if you want all nodes to use the basic category, it would be more efficient" +
" (for you and Tregex) to use a <code>TreeNormalizer</code> to remove functional" +
" tags before passing the tree to the TregexPattern. (In the GUI, a TreeNormalizer" +
" can be part of the functionality of a TreeReader specified in Preferences.)" +
" <p><h3>Segmenting patterns</h3>" +
" The \":\" operator allows you to segment a pattern into two pieces. This can simplify your pattern writing." +
" The semantics is that both patterns must match a tree, but the match of the first pattern" +
" is returned as the matching node. For example, the pattern" +
" <blockquote>" +
" S : NP" +
" </blockquote>" +
" matches only those S nodes in trees that also have an NP node (somewhere in" +
" the tree - it's location with respect to the S is unconstrained)." +
(" <p><h3>Naming nodes</h3>" +
" Nodes can be given names (a.k.a. handles) using '=', for example, " +
" <code>ADJP=ap</code>. A named node will be stored in a" +
" map that maps names to nodes so that if a match is found, the node" +
" corresponding to the named node can be extracted from the map. For" +
" example <code> (NP < NNP=name) </code> will match an NP dominating an NNP." +
" Node names have two purposes: they can be referred back to in the Tregex pattern, " +
" and, programmatically, after a match is found, the map can be queried with the" +
" name to retrieve the matched node using <code>TregexMatcher#getNode(String s)</code>" +
" with argument \"name\" (<it>not</it> \"=name\")." +
" Note that you are not allowed to name a node that is under the scope of a negation operator (the semantics would" +
" be unclear, since you can't store a node that never gets matched to)." +
" Trying to do so will cause a <code>ParseException</code> to be thrown. Named nodes <em>can</em> be put within the scope of an optionality operator." +
" <p>Secondly, named nodes can be referred back to in a Tregex pattern." +
" A named node that refers back to a previous named node need not have a node" +
" description -- this is known as \"backreferencing\". In this case, the expression" +
" will match only when all instances of the same name get matched to the same tree node." +
" For example: the pattern" +
" <blockquote>" +
" <code> (@NP <, (@NP $+ (/,/ $+ (@NP $+ /,/=comma))) <- =comma) </code>" +
" </blockquote>" +
" matches only an NP dominating exactly the sequence <code>NP , NP ,</code>" +
" - the mother NP cannot have any other daughters. Multiple" +
" backreferences are allowed. If the node with no node description does not refer" +
" to a previously named node, there will be no error; the expression simply will" +
" not match anything." +
" <p> Another way to refer to previously named nodes is with the \"link\" symbol: '~'." +
" A link is like a backreference, except that instead of having to be <i>equal to</i> the" +
" referred node, the current node only has to match the label of the referred to node." +
" A link cannot have a node description, i.e. the '~' symbol must immediately follow a" +
" relation symbol. For example, the pattern <code>ADJP=cat <, ~cat <- ~cat</code> will" +
" match all ADJP whose first and last child is also an ADJP. ") +
(" <p><h3>Variable Groups</h3>" +
" If you write a node description using a regular expression, you can assign its matching groups to variable names." +
" If more than one node has a group assigned to the same variable name, then matching will only occur when all such groups" +
" capture the same string. This is useful for enforcing coindexation constraints. The syntax is" +
" <blockquote>" +
" <code> / <regex-stuff> /#<group-number>%<variable-name></code>" +
" </blockquote>" +
" For example, the following pattern (designed for Penn Treebank trees)" +
" <blockquote>" +
" <code> @SBAR < /^WH.*-([0-9]+)$/#1%index << (__=empty < (/^-NONE-/ < /^\\*T\\*-([0-9]+)$/#1%index)) </code>" +
" </blockquote>" +
" will match only such that the WH- node under the SBAR is coindexed with the" +
" trace node that gets the name <code>empty</code>.") +
("<p><h3>Comparison with tgrep and tgrep2</h3>" +
" Tregex is similar to tgrep and tgrep2. Tregex supports all the standard operators of tgrep" +
" (but not alternative symbols), but where the semantics of tgrep2 for those operators" +
" differs, it follows tgrep2. Tregex implements many of the extensions of tgrep2, such as" +
" boolean expressions, labeled nodes, segmented patterns, and the ? operator, but not the = and ~ operators," +
" macros, nor many of the command-line options, such as for formatted output. Tregex implements" +
" some unique additions of its own, such as operators for being the head of, or domination or precedence along a constrained path," +
" and the == operator. Another big difference is that tgrep and tgrep2 pre-index treebanks, while tregex iterates" +
" through them at runtime. The latter is slower but more flexible. Two final differences are that tregex has a GUI" +
" and a companion language Tsurgeon for editing trees.") +
("<p><h3>Tsurgeon</h3>" +
" Tregex has a companion language Tsurgeon for altering trees according to rules. To use Tsurgeon (and to see" +
" the help for it), enable Tsurgeon using the <code>Preferences</code> menu item." ) +
"<p></html>";
}