Manybots - Python Natural Language Parsing

botbot.py

from nltk import pos_tag, word_tokenize
from en import verb # from http://nodebox.net/code/index.php/Linguistics
import re, pprint
from nltk.probability import ConditionalFreqDist
import os


def ie_preprocess(sentence):
    sentence = word_tokenize(sentence)
    sentence = pos_tag(sentence)
    return sentence

def findtags(tag_prefix, tagged_text):
    cfd = ConditionalFreqDist((tag, word) for (word, tag) in tagged_text
                                 if tag.startswith(tag_prefix))
    return dict((tag, cfd[tag].keys()[:5]) for tag in cfd.conditions())


def parse_sentence(input_sentence):
    # 
    tagged_sentence = input_sentence.split(' tagged with ')
    # setting the sentence as itself minus the tags (that should come at the end)
    sentence = tagged_sentence.pop(0)
    # tags
    tags = tagged_sentence

    # transforming the sentence
    tuples = ie_preprocess(sentence)
    result = {}

    # finding if there's a verb
    verbs = findtags('VBD', tuples)

    if verbs:
        verbs = verb.infinitive(verbs['VBD'][0])
        result['verbs'] = verbs
        # print 'Verb: ' + verbs

    # finding the wanted object
    objects = findtags('NNS', tuples)
    the_object = ''
    if objects:
        plural = True
        the_object = objects['NNS'][0].lower().rstrip('s')
    else:
        plural = False
        objects = findtags('NN', tuples)
        the_object = objects['NN'][0]
    
    # if plural: 
    #     the_object = the_object + ' (plural)'
    
    result['objects'] = the_object
    # print 'Object: ' + the_object


    # finding if there's a target
    target = findtags('IN', tuples)
    if target:
        target = target['IN'][0] 
    else:
        target = findtags('TO', tuples)
        if target:
            target = target['TO'][0]
    # print target

    # if there's a target, then consider all the rest the target value
    if target:
        target_value = sentence.split(target)[-1]
        result['target_values'] = target_value.strip()
        # print 'Target: ' + target_value.strip()

    if tags:
        result['tags'] = tags
        # print 'Tagged with: ' + ', '.join(tags)
    
    return result