A ideia era montar uma tabela verdade, mas eu preciso dormir...

spacy_4fun.py

# https://spacy.io/
# pip install spacy
#
#
import collections

import spacy


nlp = spacy.load('pt')


def get_first_verb(sentence: str) -> str:
    return next(item.text for item in nlp(sentence.capitalize()) if item.pos_ == 'VERB')


def get_first_verb_index(sentence: str) -> str:
    return sentence.split().index(get_first_verb(sentence))


def get_negative_form(sentence: str) -> str:

    if sentence.split()[get_first_verb_index(sentence) - 1].upper() == 'NÃO':
        return sentence  # already negative?
    return ' '.join(
        sentence.split()[:get_first_verb_index(sentence)] +
        [('NÃO ' if sentence.isupper() else 'não ' + get_first_verb(sentence))] +
        sentence.split()[(get_first_verb_index(sentence) + 1):]
    )


def get_positive_form(sentence: str) -> str:

    if sentence.split()[get_first_verb_index(sentence) - 1].upper() != 'NÃO':
        return sentence  # looks positive for me...
    return ' '.join(sentence.split()[:get_first_verb_index(sentence) - 1] + sentence.split()[get_first_verb_index(sentence):])


def get_sentence_sentiment(sentence: str) -> float:
    return collections.Counter(sentence.upper().split()).get('NÃO', 0) * -0.1


def is_sentence_negative(sentence: str) -> bool:
    return get_sentence_sentiment(sentence) < 0


def invert_sentence(sentence: str) -> str:
    if is_sentence_negative(sentence):
        return get_positive_form(sentence)
    return get_negative_form(sentence)


class Proposition:

    """Docstring for Proposition. """

    def __init__(self, sentence: str, value: bool) -> None:
        """TODO: to be defined1. """

        self._sentence = sentence
        self._value = value

    def  __repr__(self):
        return 'Proposition({}, {})'.format(self._sentence, self._value)

    def __str__(self):
        '({}),({})'.format(self._sentence, self._value)

    def __invert__(self) -> 'Proposition':
        """The negation of a proposition"""
        return Proposition(invert_sentence(self._sentence), not self._value)

    def __or__(self, other) -> 'Proposition':

        if not self._value and not other._value:
            return Proposition('', False)
        return self if self._value else other

    def __xor__(self, other):
        return Proposition('', self._value and other._value)