import nltk
import nltk as nltk

grammar = nltk.CFG.fromstring(open("atis/atis-grammar-cnf.cfg").read())
sentences = open("atis/atis-test-sentences.txt").read()
testSentences = nltk.parse.util.extract_test_sentences(sentences)

# initialize the parser
parser = nltk.parse.BottomUpChartParser(grammar)
# parse all test sentences
sentence = testSentences[12]


def isRecognized(sentence):
    return len(getParseTrees(sentence)) > 0


def getParseTrees(sentence):
    n = len(sentence)
    nonterminals = []
    trees = []
    for rule in grammar.productions():
        for word in sentence:
            if rule.rhs() == word:
                nonterminals.append(rule)

    for b in range(2,n):
        for i in range(1,n-b+1):
            for k in range(1, b-1):
                print("ahoj")

    return trees