package edu.stanford.nlp.trees;
import edu.stanford.nlp.trees.tregex.TregexMatcher;
import edu.stanford.nlp.trees.tregex.TregexPattern;
import edu.stanford.nlp.trees.tregex.TregexPatternCompiler;
/**
* Flattens the following two structures:
* <br>
* (NP (NP (NNP Month) (CD Day) )
* (, ,)
* (NP (CD Year) ))
* <br>
* becomes
* <br>
* (NP (NNP Month) (CD Day) (, ,) (CD Year) )
* <br>
* (NP (NP (NNP Month) )
* (NP (CD Year) ))
* <br>
* becomes
* <br>
* (NP (NNP Month) (CD Year))
*
* @author John Bauer
*/
public class DateTreeTransformer implements TreeTransformer {
static final String MONTH_REGEX = "January|February|March|April|May|June|July|August|September|October|November|December|Jan\\.|Feb\\.|Mar\\.|Apr\\.|Aug\\.|Sep\\.|Sept\\.|Oct\\.|Nov\\.|Dec\\.";
static final TregexPattern tregexMonthYear = TregexPatternCompiler.defaultCompiler.compile("NP=root <1 (NP <: (NNP=month <: /" + MONTH_REGEX + "/)) <2 (NP=yearnp <: (CD=year <: __)) : =root <- =yearnp");
static final TregexPattern tregexMonthDayYear = TregexPatternCompiler.defaultCompiler.compile("NP=root <1 (NP=monthdayroot <1 (NNP=month <: /" + MONTH_REGEX +"/) <2 (CD=day <: __)) <2 (/^,$/=comma <: /^,$/) <3 (NP=yearroot <: (CD=year <: __)) : (=root <- =yearroot) : (=monthdayroot <- =day)");
public Tree transformTree(Tree t) {
TregexMatcher matcher = tregexMonthYear.matcher(t);
while (matcher.find()) {
Tree root = matcher.getNode("root");
Tree month = matcher.getNode("month");
Tree year = matcher.getNode("year");
Tree[] children = new Tree[] {month, year};
root.setChildren(children);
matcher = tregexMonthYear.matcher(t);
}
matcher = tregexMonthDayYear.matcher(t);
while (matcher.find()) {
Tree root = matcher.getNode("root");
Tree month = matcher.getNode("month");
Tree day = matcher.getNode("day");
Tree comma = matcher.getNode("comma");
Tree year = matcher.getNode("year");
Tree[] children = new Tree[] {month, day, comma, year};
root.setChildren(children);
matcher = tregexMonthDayYear.matcher(t);
}
return t;
}
}