stanford_parser.py

"""Python interface to the Stanford parser.

The module wrapps the edu.stanford.npl Stanford Parser, which is
implemented in Java, using the JPype library.

The StanfordParser class wraps the actual parser, and the :func:`parse` function
can be used to parse sentences.

:Author: Gleb Sizov <sizov@idi.ntnu.no>"""

import jpype

class StanfordParser(object):
    """Class wrapping the edu.stanford.npl java parser package."""
    def __init__(self):
        #~ jpype.startJVM('C:/Program Files (x86)/Java/jdk1.6.0_21/jre/bin/client/jvm.dll', '-Xmx800m')
        #~ jpype.startJVM(jpype.getDefaultJVMPath())
        jpype.startJVM('/usr/lib/jvm/java-6-openjdk/jre/lib/amd64/server/libjvm.so', '-Xmx2000m')

        nlpPackage = jpype.JPackage('edu').stanford.nlp
        self.lexicalizedParser = nlpPackage.parser.lexparser.LexicalizedParser('englishPCFG.ser.gz')
        self.grammaticalStructureFactory  = nlpPackage.trees.PennTreebankLanguagePack().grammaticalStructureFactory()

    def apply(self, sentence):
        tree = self.lexicalizedParser.apply(sentence)
        pos = tree.taggedYield()
        #~ dependencies = self.grammaticalStructureFactory.newGrammaticalStructure(tree).typedDependencies()
        #~ dependencies = self.grammaticalStructureFactory.newGrammaticalStructure(tree).typedDependenciesCollapsed(True)
        dependencies = self.grammaticalStructureFactory.newGrammaticalStructure(tree).typedDependenciesCCprocessed(True)

        return pos, tree, dependencies

    def __del__(self):
        jpype.shutdownJVM()

parser = None

def parse(sentence):
    """Parses *sentence* and return POS-tags, parse tree and dependencies."""
    global parser
    if not parser:
        parser = StanfordParser()
    return parser.apply(sentence)

def test_parser():
    text = """The first thing to see,
looking away over the water, was a kind of dull line, that was the
woods on t' other side; you couldn't make nothing else out; then
a pale place in the sky; then more paleness spreading around; then the
river softened up away off, and warn't black any more, but gray; you
could see little dark spots drifting along ever so far away
(trading scows, and such things; and long black streaks) rafts;
sometimes you could hear a sweep screaking; or jumbled up voices,
it was so still, and sounds come so far; and by and by you could
see a streak on the water which you know by the look of the streak
that there's a snag there in a swift current which breaks on it
and makes that streak look that way; and you see the mist curl
up off of the water, and the east reddens up, and the river, and
you make out a log cabin in the edge of the woods, away on the
bank on t'other side of the river, being a wood yard, likely, and
piled by them cheats so you can throw a dog through it anywheres;
then the nice breeze springs up, and comes fanning you from over
there, so cool and fresh and sweet to smell on account of the woods
and the flowers; but sometimes not that way, because they've left
dead fish laying around, gars and such, and they do get pretty
rank; and next you've got the full day, and everything smiling in
the sun, and the song birds just going it!"""
    lim = 125
    text1 = ' '.join(text.split(' ')[0:150])
    text2 = ' '.join(text.split(' ')[0:30])
    try:
        print parse(text1)
    except jpype._jexception.JavaException as e:
        print e
        print '! Sentence too long, skipping.'
    try:
        print parse(text2)
    except jpype._jexception.JavaException as e:
        print e
        print '! Sentence too long, skipping.'

def tmp():
    text = "Transport Canada Publication 312 serves as the authoritative document for airport specifications for land airports in Canada"
    text = "The pilot was certified and qualified"
    pos, tree, dependencies = parse(text)
    print dependencies

if __name__ == '__main__':
    #~ tmp()
    for output in parse("Immediately after the second touchdown, the pilot decided to perform a go-around."): print output
    #~ test_parser()
    #~ pos, tree, dependencies = parse('A review of the radar data indicated that the aircraft approached the Liverpool airport from the east, turned south across runway 25/07 and joined the circuit left-hand downwind for runway 25.')
    #~ print pos[10].word()
    #~ print pos[10].tag()
    #~ print pos
    #~ print dependencies
    #~ print dependencies[0].reln()
    #~ print dependencies[0].gov().value()
    #~ print dependencies[0].dep().index()
    #~ print
    #~ print tree